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AirRated Anthology: The guide to indoor air quality


History of indoor air quality

  • Early beliefs
  • The Industrial revolution
  • Miasma theory
  • The Great Smog of London
  • Modern buildings

Indoor air quality: the basics

  • What is indoor air quality?
  • The five key indoor air quality parameters
  • The causes of poor indoor air quality
  • The effects of poor indoor air quality
  • The relationship between indoor and outdoor air quality
  • What is a healthy building?

Growing awareness

  • Growing awareness around indoor air quality 
  • The rise of indoor air quality monitoring 
  • The rise of building certifications 
  • The balance between green buildings and healthy buildings 
  • The value of healthy buildings

The impact of COVID-19 on indoor air quality

  • Transmission
  • The link between poor indoor air quality and COVID-19 susceptibility
  • Impact of COVID-19 on attitudes
  • How can we make buildings safer?


  • Why is indoor air quality a problem in our homes?
  • How does poor indoor air quality affect us at home?
  • How can we improve indoor air quality at home?
    • Ventilation
    • Humidity
    • Indoor pollution sources
    • Purifying the air


  • The main issues with indoor air quality in schools
  • Why are children vulnerable?
    • Traffic around schools
    • Allergies and asthma
  • What can we do?


  • Why are healthy offices so important?
  • Why is indoor air quality a problem in offices?
  • How has COVID-19 changed the workplace?
  • How can we make offices healthier?
    • Ventilation
    • Air filtration
    • Environmental monitoring
    • Raising awareness
    • Control indoor pollution sources

The future of IAQ

  • Growing awareness
  • Regulations
  • The rise of ESG
  • Better indoor air quality?

The conversation around air quality has grown hugely in recent years, with the main focus being placed on outdoor air pollution sources, such as wildfires, cars, and factories. 

Indoor air quality (IAQ), however, is discussed far less often. In a recent study published by NICE, it was reported that UK residents spend anywhere between 60% and 90% of their time indoors. And with over a year of lockdowns and quarantines in line with COVID-19 restrictions, that figure is likely to be even higher. 

The air quality in our indoor spaces – such as schools, workplaces and our homes – can have huge impacts on our health, productivity and overall wellbeing. 

In this guide, we’ve explored the key points surrounding IAQ, from early beliefs right up until what we can expect from the future of air quality. We’ve also included the major health implications of poor IAQ, as well as how to easily improve the quality of air in key indoor spaces. 

This guide is designed so you can read from top to bottom, or skip straight to the specific sections that interest you most. If you have any questions about IAQ or would like to certify the air quality of your indoor space, don’t hesitate to get in touch

1. History of indoor air quality

Early beliefs

As humans, our survival instincts tell us to escape risks to our health and livelihood. The phenomenon of poor air quality affecting our health has been documented as early as 400 BC, with Hippocrates speculating on the links between poor environments (dirty water and poor air quality) and contracting illnesses or diseases. The conclusion from this was existing in areas with fresh air and clean water – where possible – would improve our health. 

The urge to distance ourselves from unsanitary danger brings to mind COVID-19 prevention methods, with lockdowns and quarantine periods becoming standard procedure in many countries during 2020. The word quarantine itself is defined as restricting the movement of people or goods, and comes from the Latin term for ‘forty days’: referring to Middle Age attempts to prevent the spread of the bubonic plague. 

All ships arriving to Venice from locations affected by the Black Death were forced to anchor for 40 days before any crew could disembark, in order to prevent further spread of the plague. Even now, almost 700 years later, similar quarantine measures are still being taken across the world to prevent COVID-19 transmission. 

England’s last major pandemic was the Great Plague of 1665-66, but many of the ways we approach airborne disease and air quality today have their roots in age-old theories. 

For instance, the outbreak of COVID-19 saw face coverings being adopted across most of the world, but the history of mask wearing in deadly pandemics stretches back hundreds of years. During the Great Plague, physicians treating infected victims were covered head to toe, an outfit that was completed by a sinister-looking beaked face mask. 

Engraving of the Plague Doctor, Paul Fürst, c. 1656.

According to 17th century physician Charles de Lorme, the iconic mask was: ‘half a foot long, shaped like a beak, filled with perfume with only two holes, one on each side near the nostrils, but that can suffice to breathe and carry along with the air one breathes the impression of the [herbs] enclosed further along in the beak.’ 

The mask may have been intended to protect these doctors from miasma – a theory we discuss later in further detail, which has long since been disproved. However, with hazmat suits, sterile gloves, and masks being common in any healthcare facility, the principle of using physical barriers to protect ourselves from infection has endured to present day.

The Industrial Revolution

The 18th century Industrial Revolution marked a period of development across Europe and the United States, where rural societies were transformed into industrial cities. It was a turning point, where manufacturing processes, steam power, and water power meant hand-crafting production methods were replaced by machinery. 

The rapid urbanisation during this time led to the expansion of cities, which quickly resulted in overcrowded streets, pollution, and a lack of sanitation, especially in densely populated cities like New York and London. This was compounded by unprecedented population growth, and outbreaks of diseases such as typhoid and cholera became public health issues. 

The construction of huge factories and immense coal consumption led to widespread air pollution in industrial areas. This sparked grass-roots campaigns tackling both water and air pollution, as well as the first modern environmental laws to be passed in 1863 in an attempt to regulate the extent of the smoke, dust and fumes polluting the air. 

Miasma theory

Miasma theory is a belief that was at its most popular in the 19th century, and states that contagious diseases are spread and caught through coming into contact with ‘bad air’. The word ‘miasma’ comes from the Greek word for ‘pollution’ and dates back to the Middle Ages and, before that, Hippocrates. 

Although it was eventually proved obsolete for illnesses spread through other means (such as through unsanitary water or mosquitos), the theory still stands for airborne infections such as chickenpox, the flu and, more recently, coronavirus. 

During the 19th century, many healthcare professionals informed their practices according to miasma theory. Florence Nightingale was one such nurse who believed it was essential to remove the ‘bad air’ in order to minimise the spread of disease. This led to features such as ventilation being integral to building construction: 19th century hospitals and homes were built to create a continuous flow of air. 

While our understanding of diseases has progressed significantly since the 1800s, one thing remains clear: good air quality and adequate ventilation really does benefit our health. 

The Great Smog of London

The Great Smog of 1952 was a defining moment in the conversation surrounding air quality. Heavy, thick fog during this period was not uncommon in London, but 5th December saw an impenetrable veil unlike any other. Within a few hours, a yellow-brown fog covered London, mixing with smoke being pumped out of factories, chimneys, and vehicles across the capital.

The smog was an air mass stretching for 30-miles-wide, and was so thick that road and boat transport came to a halt. People had difficulty seeing their feet beneath them, pickpocketing increased, and children were kept home from school for fear of them getting lost in the blanket of smog. 

London police officer surrounded by smog

Five days later, on 9th December, Londoners finally breathed a sigh of relief as a brisk western wind cleared the smog, but a lethal legacy was left behind. Heavy smokers, children, the eldery, and those with respiratory problems were all particularly affected by the air pollution: deaths from lung conditions like bronchitis and pneumonia increased by seven times. At the time, it was estimated that 4,000 deaths were caused by the event, but modern experts estimate that somewhere between 8,000 and 12,000 deaths occurred prematurely as a result of the Great Smog. 

Although the city was slow to react and government officials lacked a sense of urgency due to the frequency of heavy fog at the time, the Clean Air Act was eventually passed in 1956. This prohibited the emission of dark smoke from chimneys in many urban areas, with some councils establishing smoke-free zones. 

During the 50s and 60s, the city mostly replaced coal with gas, oil and electricity – but this transition was slow. Londoners experienced a similar air pollution event in 1962, which claimed the lives of around 750 people. Although the city hasn’t experienced a visible smog to this extent recently, air pollution still regularly exceeds legal limits: there’s a reason why London is known as ‘The Big Smoke’.

As Alex Werner from the Museum of London said: ‘It was a popular term among visitors from rural areas. As they approached London they saw a thick smoke enveloping the city, which was largely caused by the burning of coal.’

Modern buildings 

The quest for energy efficiency and cost savings has led to a modern building phenomenon: the rise of hermetically sealed boxes. The Building Regulations standard first included levels of air tightness in all new buildings back in the 1970s. As of 2010, newly built dwellings must still meet the limit of air tightness, allowing no more than 10m3 to leak an hour

These buildings are a far cry from the ventilation-centric constructions of the 19th century; they may be economic and well-insulated, but they leave much to be desired when it comes to environmental and health benefits. 

Standard practice is often to use central heating when necessary, keeping windows and doors shut unless it’s warm outside. This creates insulated, air-tight boxes that promote mould growth and trap pollutants indoors. This means that our homes, schools, offices, and many public buildings are at risk of having air quality so poor that our health suffers as a result. 

Although the conversation around indoor air quality (IAQ) is growing in popularity, research and awareness falls short of where it needs to be. With the outbreak of COVID-19 in 2020, the health of our indoor spaces moved into public discussion and we returned to old methods of disease prevention. Quaratines, lockdowns, and a focus on ventilation have all been vital in stopping the spread of COVID-19, but what we really need is a long-lasting improvement to our built environments. 

The need for healthier buildings and more awareness around IAQ is clear; buildings must be designed with the health and wellbeing of occupants at the heart. Far too often, healthy indoor spaces are reserved for those who can afford it, with social housing falling short of basic recommendations. Eventually COVID-19 will become a controllable part of our lives, or a distant memory, but the need to improve our air-tight buildings will remain. 

2. Indoor air quality: the basics

What is indoor air quality?

Indoor air quality (IAQ) describes the quality of air inside and surrounding a built space. It’s often discussed in relation to the health, comfort and wellbeing of building occupants. IAQ can be affected by a range of factors, such as ventilation, building layout and surrounding traffic pollution. 

The five key parameters

When measuring the IAQ of a space, there are five key parameters which significantly impact the quality of air.

  1. PM2.5

Fine particulate matter, such as dust, sea salt and ash that comes from a number of sources. These particles can penetrate the lungs and bloodstream, causing irritation of airways, cardiovascular issues, and even reduce life expectancy. 

  1. CO₂

Carbon dioxide is a colourless, odourless gas that occurs naturally in the air: main sources of indoor CO₂ are respiration (both human and animal) and combustion. Although it’s naturally part of the air we breathe, even very low levels of CO₂ can cause adverse health effects, impair cognitive function and aggravate respiratory problems. 

  1. TVOCs

TVOCs is the collective term for a group of Volatile Organic Compounds (VOCs), compounds that can become gases or vapours. Examples include acetone, benzene and formaldehyde, and they can come from construction and furnishing products, cleaning refrigerants. Short- and long-term exposure to these can cause a range of health issues, from dizziness to central nervous system damage. 

  1. Temperature

Room temperature describes the preferred air temperatures for an indoor setting; research indicates that the optimal room temperature is between 21°C to 22°C. Indoor temperature is affected by many variables from occupant density to mechanical ventilation, and an uncomfortable temperature can contribute to Sick Building Syndrome (SBS) symptoms, such as headaches, itchy skin, sore eyes, blocked noses, and rashes. 

  1. Humidity

Relative humidity refers to the concentration of water vapour present in the air, and can be affected by occupant respiration, and activities such as cooking and washing. Both high and low humidity directly affect health, comfort, and the presence of biological pollutants such as mould spores, and can cause damaging respiratory infections.

To learn about the key air quality parameters in more detail, have a look at this article. 

Causes of poor indoor air quality

Poor air quality is a public health crisis, with the UK government reporting it as the largest environmental risk to public health. The majority of the world’s inhabitants have no choice but to breathe polluted air every day, with research estimating that air pollution causes a staggering 8.9 million premature deaths worldwide annually.

A small amount of air pollutants are emitted from natural sources, such as wildfires, volcanic ash, and sea spray salt. However, most air pollution is caused by burning of fossil fuels, such as coal and gasoline. Air pollution is most frequently discussed in relation to outdoor spaces, with focus usually being on our roads, however indoor air pollution is a huge issue which causes poor indoor air quality. 

The air inside our homes, offices, and public spaces can be affected by a number of factors. Common causes of poor IAQ include:


  • Chemicals from cleaning products, varnishes, air fresheners, candles
  • Mould or damp
  • CO₂ from building occupants
  • Perfumes
  • Tobacco smoke
  • Dust and animal dander
  • Asbestos in building materials
  • Dust mites
  • Gases and PM2.5 from cooking
  • PM2.5 from burning wood or coal
  • In extremely polluted areas, open windows can lead to pollutants, such as vehicle fumes, entering the room

Environmental factors: 

  • Inadequate temperature
  • High or low humidity
  • Poor air circulation
  • Insufficient ventilation

Take a look at this interactive flowchart by NICE for a comprehensive look into air pollution at home and on the streets. 

Effects of poor indoor air quality

Exposure to poor IAQ can have various effects on the body, and these symptoms are usually felt after several hours of being in this environment. Poor thermal comfort and high or low humidity levels can cause a range of undesirable effects, including headaches, dizziness, and lack of concentration.

Air pollution has a wide range of impacts on the body, with irritation of the eyes, nose and throat being the most common complaints. When pollutants enter the body at any stage of life, they can cause gradual and long-lasting damage. 

Pollutants cause damage by affecting our vital organs and physiological systems, from the airways to the lungs and respiratory system, and even the heart.

Short-term effects of air pollution:

  • Respiratory illnesses
  • Irritation of nasal passages, airways, eyes, and skin
  • Headaches and dizziness
  • Worsening or asthma symptoms
  • Coughing and sneezing

Long-term effects of air pollution:

  • Strokes
  • Cardiovascular disease
  • Respiratory disease
  • Lung cancer
  • Reduced life expectancy

Air pollution is a huge topic that is still being widely researched. Emerging evidence suggests that air pollution may have links to cognitive function, causing premature decline, dementia, and mental health issues in children. 

Poor IAQ can also impact our quality of sleep, causing subsequent issues such as high blood pressure, depression, and cardiovascular issues. Take a look at our blog post to read more about how you can get a better night’s sleep by improving your air quality. 

The relationship between indoor and outdoor air quality

The conversation surrounding air quality usually centres around outdoor pollutants, such as car exhausts, factory fumes, and fuel consumption. IAQ is discussed far less, and indoor and outdoor air quality are rarely connected. Despite this, the two are actually intrinsically linked. 

Outdoor air pollution is responsible for as many as 6% of global deaths, and in some countries this figure can even exceed 10% of overall deaths. It’s also crucial to note that in cities like London, poor outdoor air quality disproportionately affects certain demographic groups, such as people of colour and those from lower income backgrounds. To learn more about action being taken to combat this disparity, read our interview with Destiny Boka-Batesa from the Choked Up campaign.

Outdoors, concentrations of outdoor pollutants vary greatly due to weather changes, climate, and human behaviour. During low temperatures, warm air rises to the upper atmosphere, trapping cold air at a lower level and causing a build-up of pollutants. There is also a significant rise in pollutants during periods such as rush hour traffic in the morning and evening, but wind and heat quickly clear this excess. Although outdoor air quality is an important topic, the Earth essentially has natural methods of purifying the air outside and dispersing pollutants.

The average British or American person spends as much as 90% of their time indoors, with that figure only increasing as a result of COVID-19 lockdowns and quarantines. Indoor spaces are often far more polluted than many people realise, and long-term exposure to these pollutants can cause serious health issues. 

Indoors, there are far fewer natural methods of clearing pollutants. Ventilation, such as trickle vents and open windows, bring in ‘fresh’ outdoor air, but this often introduces more pollutants indoors. These pollutants are then not cleared nearly as quickly as they are outside, because they become trapped in our homes, offices, and schools. A 2019 study published by the International Journal of Environmental Research and Public Health looked at houses in the vicinity of long-range wildfire plumes: they found that indoor concentrations of PM2.5 were up to 4.6 times higher than those found outdoors. 

According to the World Health Organization (WHO), as many as 3.8 million premature deaths are caused worldwide from illnesses worsened by household air pollution. Indoors, pollutants such as toxic products, and burning solid fuels, accumulate, and can be compounded by the introduction of outdoor pollutants. 

We often assume that air outside will be better than that indoors; or conversely, that indoor spaces in heavily polluted areas are protected from the pollution outdoors. Neither of these assumptions are correct. The exchange of air is constant and works both ways, meaning we cannot improve the quality of one while ignoring the other. 

What is a healthy building?

The term ‘healthy building’ describes an indoor space which promotes the physical and psychological health and wellbeing of its occupants. Healthy buildings can be created through optimal temperature, good ventilation, and reasonable humidity levels – all of which contribute to good IAQ – as well as factors like adequate natural light and low noise levels. 

The healthy building movement dates back to around a decade, but gained traction in 2019 when it became an integral part of the GRESB rating. The benefits of healthy buildings are plenty, with research showing an increase in productivity, reduction in employee absenteeism and improved workplace satisfaction. On top of this, a survey by the World Green Building Council found that 46% of building owners reported ‘healthy’ buildings were easier to lease. 

3. Growing awareness

Growing awareness around indoor air quality 

Air quality in general has been a topic in public consciousness for the past few decades, but the conversation has only recently shifted to include the quality of our indoor air. 

Several resources already exist to raise awareness and provide information about out air quality, such as:

  • BreezoMeter 
  • DEFRA Air Information Resource
  • London Air 
  • Air Quality in England

We recently spoke to the CEO and co-founder of BreezoMeter about how they’re reducing exposure to air pollution for billions of people worldwide. Read the conversation here

However, accessing information about IAQ is still more difficult. Websites like Indoor Air Pollution provide useful data and tips about indoor air pollution, but there still needs to be work done in raising awareness about the dangers of IAQ and how it can be improved. 

In a survey we conducted in 2020, we found that there was a 57% increase in IAQ awareness – showing it’s a topic gaining considerable traction in recent years. However, participants overwhelmingly reported they were more connected about the quality of air outdoors. 

The most notable trigger for increasing IAQ awareness was the outbreak of the COVID-19 pandemic in 2020. The airborne virus forced air quality into public conversation, with government guidelines advising fresh air and ventilation in order to reduce risk of transmission. 

For many people, this was the first time IAQ became a topic of interest. A knock-on effect of this increased awareness was a wider concern for other air quality parameters and how they impact our health. 

The value of both good outdoor and indoor air quality is finally being recognised, although much still needs to be done to make IAQ data and monitoring more widely available, as well as educating people on how they can improve IAQ themselves. Read this article for low-cost tips on how you can improve the quality of air in indoor spaces. 

The rise of IAQ monitoring 

As the awareness around IAQ has grown, so too has the market for IAQ monitoring. Research has shown how air quality can have a huge impact on productivity, cognitive function, and overall wellbeing. Monitoring the quality of our indoor air is an effective way of improving occupant satisfaction in a quantifiable way.

Employers, employees, and landlords alike are becoming more aware of the importance of being surrounded by clean, healthy air – as well as the dangers that come with exposure to poor IAQ. 

Carbon monoxide monitors are commonplace in homes and workplaces, but the COVID-19 pandemic has pushed monitoring of other air quality factors into mainstream consciousness. 

As well as this increased public interest, greater accessibility to data and the rise of affordable products have made IAQ monitoring available to more people than ever before. Many of these devices are portable and battery-operated, such as Airthings’ range of sensors, meaning implementation is quick and simple. 

Another popular IAQ solution is the Flow sensor, developed by Paris-based company, Plume Labs, which uses a tiny fan to take in air while lasers and membranes detect harmful pollutants. Products such as these are revolutionising the IAQ monitoring space, making this information accessible and easy to interpret. 

Andrew Teacher, founder at Blackstock Consulting and an executive committee member at the Urban Land Institute explains: ‘The step change has been driven by the rise of consumer products that present air quality data in an accessible and dynamic way. There’s a proliferation of sensors, data and technology, which means it’s getting cheaper to understand how healthy both indoor and outdoor spaces are.’ 

This technology will only continue to evolve. Many smartphone weather apps already allow you to check the outdoor air quality of your location: it’s only a matter of time until real-time IAQ monitoring will be widely available at our fingertips. 

The rise of building certifications 

In recent years, building certifications have become an increasingly important feature in commercial and residential properties. Using third-party certifications are great ways of enhancing the appeal of a building, as well as communicating its health to occupants. 

These certifications are clear ways to signify different factors in a built space, from quality of air to how sustainable the building is. Many academic studies show how building certifications can increase its value, with the World Bank Group finding buildings with green certifications have 23% higher occupancy rates compared to those without. 

LEED is one of the most widely used building rating systems used globally, focusing on the health, efficiency and sustainability of green buildings. Over 32,500 buildings have been certified across 162 countries worldwide. The benefits of a LEED certification are abundant, with The U.S. Green Building Council commending the competitive edge it provides to property owners.

WELL Certification places emphasis on human health and the wellbeing of a building’s occupants, with over 4,000 registered projects worldwide. It considers indoor factors such as water, thermal comfort, sound, and light, as well as air quality. The Green Business Certification Incorporation, GBCI, administers both the WELL Building Standard and the LEED certification, and they can be awarded to complement each other. 

BREEAM’s rating system measures a range of factors, from land use and pollution to health and wellbeing. First launched in 1990, it’s the world’s longest running building certification with over 550,000 certified buildings. 

GRESB carries out an annual survey-based assessment to measure ESG performance and sustainability practices in the commercial real estate industry. Founded in 2009, GRESB focuses on the need for understanding and disclosure of this information.

These certifications all consider air quality as a critical index in their rating system, but there are also certifications that focus solely on IAQ, such as our award: the AirScore. Read about the collaboration between AirRated and GRESB here.

There has been mounting pressure on the government to introduce building certifications as mandatory; with the British Engineering Services Association (BESA) recently urging legislation changes to be made to make IAQ monitoring and measuring compulsory. As building certifications become commonplace and environmental monitoring data is more widely available, this pressure will continue to grow. Were IAQ monitoring to be mandatory, everyone would have access to good quality air indoors, regardless of their industry or income.

The balance between green buildings and healthy buildings

Previously, conversations about green buildings placed emphasis on environmental impact and improving sustainability, through the addition of plants, solar panels, and reducing energy usage. 

The tide has recently changed. Over the past few years, there has been a shift to focus on buildings that not only benefit the environment, but also positively affect their occupants. As mentioned in ‘IAQ: the basics’, a healthy building is an indoor space that promotes the overall health and wellbeing of the people inside it. A building that is healthy and green does this whilst minimising its environmental impact. If you’re interested in some real-life examples, take a look at our list of five of the most sustainable, healthy buildings in London. 

A study in Australia found that among tenants, overall health was 15% higher for those in Green Star certified buildings, compared to conventional spaces. Likewise, occupants of Bentall-Kennedy’s green buildings in the US reported their satisfaction to be 6% higher than those in non-green certified buildings.

The demand for healthy, green buildings has long been present, but the pandemic has accelerated the movement away from simply making a building sustainable. On the popularity of green buildings, Tomáš Jurdák, Head of Real Estate at MiddleCap, states: ‘The shift towards healthy buildings happened around 8-10 years ago, when the focus, which was originally on the investment quality of a space, moved towards the quality provided to occupiers. So this trend has actually been around for a very long time, but the importance is only being fully realised now with the COVID-19 pandemic.’ 

Health and wellbeing are now front of mind across the globe. People are acutely aware of how their health is affected by indoor spaces, and both employers and landlords are feeling the pressure to address these considerations and implement adequate protective measures. 

Pandemic-induced public awareness has coincided with the widespread availability of data and evolving technology, which allows people to better visualise the impact of buildings on the environment and their own health. Addressing health concerns in buildings is no longer a luxury, it is a necessity for any office or public space.

The value of healthy buildings

As we mentioned in ‘Indoor air quality: the basics’, a healthy building is one that improves occupant health and wellbeing while minimising its environmental impact. Smart technology is used to automate and improve the functionality of many systems, such as smart cleaning and environmental monitoring. 

Healthy buildings can bring a huge amount of value to a property, with benefits for both occupants and the environment. 

Benefits to occupants

Healthy buildings are particularly valuable post-pandemic, where the focus on the health of our indoor spaces has never been greater. To get a better understanding of why COVID-19 has magnified safety concerns in the workplace, read this article.  

Occupants directly benefit from healthy buildings in a number of ways:

  • Better IAQ increases productivity levels and overall wellbeing
  • Automated Legionella monitoring can increase water safety
  • Optimal temperature levels improve employee satisfaction
  • Clear, accurate data gives employees agency and understanding over their environment

Environmental benefits

Traditional green buildings placed emphasis on design, building materials, and building compliance over effectiveness and data-driven results linked to health and wellbeing. The healthy buildings movement has instead incorporated the presence of real-time data and accurate monitoring systems.

This shift effectively drives environmental benefits such as:

  • Real-time measurement of energy and emission consumption 
  • Occupancy and capacity monitoring, which gives accurate insight into the usage of a certain space
    • These data sets can be cross referenced to optimise energy use and reduce wastage
  • Smart cleaning schedules, which can improve health and safety while using non-polluting chemicals

Positives for landlords and building managers

With monitoring systems becoming more accessible, ensuring environments that benefit the wellbeing of occupants while being environmentally conscious is easier than ever. From a landlord or building management perspective, creating healthy buildings is hugely valuable:

  • Healthy environments reduce safety risks
  • Without good air quality, landlords can face shorter leases, longer void times and higher maintenance costs
  • Easily communicate the healthy environment to occupants, making attracting and retaining tenants and employees easier

The pandemic has really pushed the demand for healthy buildings forward, placing an emphasis on the health of our indoor environments and the air we breathe. Tomáš Jurdák, Real Estate Partner at MiddleCap, states that healthy buildings are essential for longer-term value and future-proofing of the office: ‘Developers and investors are realising that the future-proofing and resilience of buildings is not just based on profitability, it is also based on the benefits a space brings to its occupiers.’ 

4. The impact of COVID-19 on IAQ


An enduring theme throughout the entire COVID-19 pandemic has been debate; with conflicting opinions about guidance like mask-wearing and quarantine lengths, disagreement among health experts and scientists has been rampant. 

One of the first debates was about how the virus is actually transmitted. Many countries responded to worries that the virus was spread via direct contact with fomites by implementing strict hand washing guidance. However, it was soon established that droplets were actually the issue. This meant the airborne virus was spread most commonly through coughing and sneezing, as well as social activities like talking and singing. This meant that a focus on hand washing soon shifted to ventilation and fresh air, while maintaining social distancing advice. 

The link between poor indoor air quality and COVID-19 susceptibility

As soon as health experts realised coronavirus was an airborne disease, the topic of air quality came into conversation. A study by Yaron Ogen from the Martin Luther University of Halle-Wittenberg in Germany investigated the impact air pollution had on COVID-19 fatalities: findings showed that NO₂ is linked to higher COVID-19 death rates.

A second study, published in Cardiovascular Research, took data from across the entire world, analysing early COVID-19 data, US and China studies on air pollution, 2003 SARS outbreak data, and additional data from Italy. 

Researchers concluded that poor air quality could have contributed to as many as 15% of COVID-19 deaths. Of this research, co-author Professor Jos Lelieveld said: ‘In the UK there have been over 44,000 coronavirus deaths and we estimate that the fraction attributable to air pollution is 14%, meaning that more than 6,100 deaths could be attributed to air pollution.’ 

At the time of writing (July 2021), COVID-19 deaths in the UK have surpassed 128,000, and links between poor IAQ and death from the disease are not concrete. It’s key to understand that there is not a causal link between air pollution and death from COVID-19, but researchers are supporting the idea that there’s an indirect link between the two. 

On this connection, co-author Professor Münzel explained that long-term exposure to polluted air leads to inflammation and oxidative stress in our blood vessels, causing damage to the lining of arteries, endothelium, and causes arteries to stiffen and narrow. The COVID-19 virus also causes similar damage to blood vessels, so both factors could compound damage to the victim. 

‘If both long-term exposure to air pollution and infection with the COVID-19 virus come together then we have an additive adverse effect on health, particularly with respect to the heart and blood vessels, which leads to greater vulnerability and less resilience to COVID-19. If you already have heart disease, then air pollution and coronavirus infection will cause trouble that can lead to heart attacks, heart failure and stroke.’ – Professor Münzel.

Although healthcare professionals and scientists have made outstanding progress on developing vaccines and controlling spread of the virus, the report authors are keen to remind us that there are ‘no vaccines against poor air quality and climate change. […] The transition to a green economy with clean, renewable energy sources will further both environmental and public health locally through improved air quality and globally by limiting climate change.’

The impact of COVID-19 on attitudes

An unexpected outcome of the global pandemic is that it’s suddenly pushed air quality, more specifically IAQ, into mainstream conversation. Understanding how the virus is transmitted has spotlighted the health of our indoor environments, highlighting the need for better ventilated spaces and improved air quality at large. 

Air quality in our homes, workplaces, and public buildings has long been a cause for concern – but lack of urgency has led to IAQ falling to the sidelines. Now the general public, rather than just experts, are involved in conversations about air quality. People are rightly beginning to demand more from their employers and landlords so that their everyday spaces are safe and healthy. If you want to learn more, read about how the pandemic may shape the built environment for good here

Growth in the air quality sensor market shows that COVID-19 has been a catalyst for growing interest in IAQ; the global market was valued at $878.62 million USD in 2019, and is forecast to reach $1,266.07 million USD by 2027. Understanding the quality of our indoor air is no longer optional, for many it’s a necessity. 

A study by Carbon Lighthouse looked at participant attitudes towards IAQ and COVID-19, and found that 91% considered IAQ to be essential in preventing transmission of the virus. 

Survey by Carbon Lighthouse

How can we make buildings safer? 

The catalyst of the pandemic will have a long-lasting effect on the modern built environment. There’s no longer any doubt that the health of our buildings must be improved: not only to reduce the transmission of COVID-19 and other illnesses, but also to prevent issues like Sick Building Syndrome (SBS), as well as improving productivity and overall wellbeing. 

Inadequate ventilation is a common issue in many of our buildings, with windows often remaining shut the majority of the year. Better ventilation systems will play a crucial role in improving IAQ, preventing transmission of airborne infections, and improving wellbeing of tenants. 

Discussing the prevention of viral transmission specifically, Francesca Brady, CEO here at AirRated, says: ‘Appropriate building controls include effective ventilation, enhanced by particle filtration, avoiding the recirculation of air and avoiding overcrowding. The implementation of these strategies throughout buildings, in conjunction with other methods of mitigation, including social distancing and hand hygiene, will be an important measure to reduce the likelihood of transmission, thereby protecting occupants.’

Another important step in improving IAQ is installing air purification systems, which should be prioritised by building owners. Filters with HEPA (high-efficiency particulate absorbing) technology work by capturing particles within the air, such as COVID-19 particles, and removing them from the air. On a wider scale, they can remove pollutants such as toxic chemicals, making indoor spaces cleaner and healthier. 

Real-time environmental monitoring is another vital tool in creating healthier buildings. Air quality parameters, such as: temperature, humidity, CO₂, PM2.5 (particulate matter) and more can be accurately monitored. Additionally, occupancy and capacity monitoring are great ways of ensuring building occupants do not exceed safe social distancing guidelines. Good monitoring systems will have the enablement of real-time alerts, meaning any factors that fall outside optimal levels can be rectified as soon as possible. 

The benefits of ongoing environmental monitoring stretch far beyond the prevention of COVID-19; it’s a valuable method of creating an indoor space that truly considers the health and wellbeing of its occupants. 

To better understand how you can reduce the risk of COVID-19 transmission in your home and other indoor environments, read this article

5. Homes

2020 was the year of the ‘stay at home’ order. With various lockdowns and social distancing measures meaning many favourite bars and cafes were closed, we all spent more time than ever before inside our houses.

In the same way that the pandemic has altered our relationship with public spaces and offices, the dynamic of our homes has too changed. For many, our houses had to take on the role of schools and workplaces, and despite people being keen to return to normality, aspects of this change will undoubtedly remain in some form. 

Spending more time in our homes has forced many of us to recognise the health and safety of these environments. The importance of good IAQ is now a topic of discussion, and we all have the power to improve this in our own homes. As the NHS says, ‘good health starts at home’.

However, general awareness and understanding of IAQ is still lagging behind that of outdoor air quality. In a survey we commissioned, 57% respondents said their awareness of IAQ increased in 2020; this is certainly promising. But as more people are working remotely, or adopting a hybrid schedule, spending more time in our houses will become the norm as we come out of the pandemic. 

It’s crucial that people understand the importance of improving air quality in their houses, what contributes to poor air quality, and the changes they can make to improve the health of their homes. 

Take a look at our blog post for a deeper dive into IAQ and the property industry. 

Why is indoor air quality a problem in our homes? 

For the past 50 years, buildings – homes in particular – have been designed with a focus on energy efficiency and heat retention. As a result, many modern buildings are now hermetically sealed boxes. This may reduce heating bills, but insufficient advice about ventilation has led to these spaces being detrimental to occupant health. 

This issue is exacerbated through everyday, often unavoidable, activities. Cooking, lighting candles or open fires, drying laundry and cleaning with harmful products all contribute to poor IAQ. If a space isn’t ventilated properly, resultant pollutants can build up and cause a range of health symptoms. 

‘Outdoor air has been regulated for decades, but emissions from daily domestic activities may be more dangerous than anyone imagined,’ The New Yorker, 2019.

While there are ways of mitigating this – such as through third-party environmental certifications and better ventilation systems – financial circumstances mean that this is inaccessible to many people. On top of this, they’re often simply not provided with the basic information necessary to understand the health implications of exposure to poor air quality. Social housing in particular often fails to hit recommended standards for IAQ, and tenants have minimal control over rectifying this issue. 

How does poor indoor air quality affect us at home?

  1. Health

Exposure to poor IAQ has numerous detrimental effects on our health, from irritating airways, sinuses and throats to worsening health conditions like asthma. NICE recently published research stating that in the UK, people spend anywhere between 60% and 90% of their time indoors. Around 60% of this is in the home – a figure which is only going to grow as people work in their homes more frequently. 

When exposed to pollutants and subpar humidity levels in the home, many aspects of everyday life can be impacted. 

To get a more in-depth explanation of the dangers of poor IAQ, refer to ‘effects of poor IAQ’ in IAQ: the basics

  1. Sleep

Studies have shown that exposure to indoor air pollution can directly affect quality of sleep – which has numerous health impacts in itself. One study found that participants exposed to higher levels of airborne pollutants had lower sleep efficiency than those with better IAQ. 

This is thought to be down to sleep disruption and breathing problems caused by irritated airways and dry lips. However Martha Billings, co-author of the study, hypothesised that pollutants such as nitrogen and PM2.5 entering our bloodstream during sleep could have a direct effect on the brain, further impacting breathing ability and causing intermittent sleep. 

When we consider outdoor environmental factors, studies have found that people who live in highly polluted areas can be up to 60% more likely to have poor sleep quality. To learn more about the effects of air quality on sleep and how to rectify this issue, read this article

  1. Productivity

Rooms with a high concentration of people and insufficient ventilation can quickly accumulate levels of carbon dioxide through exhalation. High amounts of CO₂ in our blood prevents the adequate metabolization of oxygen; this impacts cognitive function, causes tiredness, and hinders productivity. As our homes have become our workplaces, this dip in productivity could cause serious issues to our daily output. Read more about the links between CO₂ and productivity here

How can we improve indoor air quality at home?

Ensuring good IAQ is essential for health and wellbeing, as well as maximising our productivity. Although IAQ can be improved through expensive devices, these options aren’t always accessible to everyone. 

A great first step is to invest in IAQ sensors in your home, this way you’ll be able to gain a better understanding of the air quality within your house, and what areas need improvement. There are plenty of sensors on the market to monitor key air quality factors, such as:

  • Temperature
  • Humidity
  • CO₂ (carbon dioxide)
  • CO (carbon monoxide)
  • NO₂ (nitrogen dioxide)
  • O3 (atmospheric ozone)
  • VOCs (volatile organic compounds)
  • PM2.5 (fine particulate matter)

Beyond this, we’ve rounded up the four main focus areas to improving the health of your environment; following these recommendations and making small lifestyle changes will have a significant impact on the quality of the air in your home. 

  • Ventilation
  • Humidity
  • Indoor pollution sources
  • Purifying the air
  1. Ventilation

Adequate ventilation is a crucial contributor to improving the IAQ in your home – it’s also one of the cheapest and easiest ways to do so. Creating a flow of fresh air will dilute any pollutants that have built up, replace high levels of CO₂ with oxygen, and reduce high levels of humidity to prevent damp. 

Depending on the setup of your house, you can either open windows and indoor doors to create a flow of air, or open trickle vents if they’re fitted in your home. It’s particularly advisable to do this when dusting, vacuuming or cooking, as well as during the night when outdoor pollution levels are at their lowest. 

It’s good to note that if you live in a particularly high pollution area or suffer from pollen allergies, using background ventilation like trickle vents, or mechanical ventilation systems like extractor fans in the bathroom and kitchen will have a more positive effect on your health. 

It may feel like a waste of money to create these draughts, particularly during the winter months or when central heating is switched on, but the health benefits definitely outweigh any small temperature changes (and they really will be minimal!).

If your circumstance allows, installing a Positive Input Ventilation (PIV) system is an effective, low-maintenance method of creating a constant flow of filtered air through your home. It can be fitted in a loft space for minimal disruption, and recommended PIV units have low-energy motors that will minimise running costs.

Dust mites are another key reason to ensure your home is properly ventilated. They are microscopic insects that feed on skin that’s been shed. They’re found throughout the house, particularly on soft furnishings, carpets and mattresses. In a recent survey, 60% of asthma sufferers stated that dust mites trigger their asthma. Dust mite allergy is actually the biggest asthma trigger worldwide as asthmatics are more vulnerable to this allergy than the general population. 

It’s impossible to create a completely dust mite-free home, but there are steps that can be taken to reduce their presence to avoid aggravating conditions like asthma. 

Ventilation is key in this process; dust mites thrive in humid, dusty environments so airing rooms – particularly bedrooms and living areas – is key. Additionally, cleaning bed sheets, cushion covers and soft toys is essential; this can easily be done through regular vacuuming or laundering items at high temperatures.

  1. Humidity

The recommended humidity level for a UK home is between 40-60%. Houses that fall outside these optimal levels – either too high or too low – can cause damage to both our health and homes. 

Humidity levels in UK homes are often too high, with central heating and closed doors and windows causing moisture to be trapped indoors. If you’re interested in the relationship between temperature and relative humidity, watch this video from Tomas O’Leary. 

High humidity in homes can be daily activities, such as cooking, bathing and showering, and air-drying clothes. Although it’s impossible to avoid these activities completely, many steps can be taken to offset the moisture they release into the air. 

As previously mentioned, increasing ventilation in particularly humid rooms is an effective way of removing any moist air, as well as preventing condensation. If this is insufficient, investing in a dehumidifier and making use of extractor fans are great ways of limiting the growth of mould. 

Low humidity areas can cause just as many health issues as excess moisture, drying out mucus membranes in our airways and increasing susceptibility to bacteria and viruses. This can be easily helped through the use of a humidifier, or even keeping a pot of water boiling to release moisture back into the air. 

  1. Indoor pollution sources

One of the most effective ways of improving IAQ is controlling pollutants right at their source. 

Heating and candles

A main contributor to high levels of PM2.5 in the home is the use of open fires and unvented space or paraffin heaters, so it’s wise to avoid these methods of heating where possible – or ensure proper ventilation if they must be used. To learn more about the dangers of wood-burning stoves in particular, read this article. The use of candles and air fresheners also release PM2.5 into the air, so it’s better to opt for non-toxic candles made of soy or beeswax if possible. 


We’ve already mentioned the benefits of using an extractor fan while cooking, and there are even more easy steps that can be taken to ensure pollutants released when cooking don’t compromise your IAQ. One easy step is to close doors and open windows, creating a flow of air to drive pollutants out of your home.

Opting for electrical appliances over gas is another great way to lower NO₂ emissions within your home. Additionally, self-cleaning ovens are effective at regularly removing any pollutants that have built up in the appliance – just make sure no one’s in the room while it’s doing the job. 


Toxic chemicals occur in many household products, such as varnishes, sealants, and common cleaning products. Cleaning your home regularly is an effective way of removing any pollutants that have built up, such as dust, animal dander, and mould. However, it’s important to use materials that aren’t damaging to your health. 

Opting for non-toxic or natural cleaning products will minimise the amount of VOCs that are released into the air, such as those made by Bower Collective – a company on a mission to create cleaning products that are better for our homes and the planet. Read our recent interview with their founder Nick Torday here

A study conducted by Awair compared both green and non-green cleaning products, and found that non-green products increased VOC levels almost 15 times more than their green counterparts.

Results of Awair’s study into green and non-green cleaning products

Vacuuming rugs and carpets once or twice a week is also key to remove a build up of particulate matter. However, it’s better to opt for a vacuum cleaner with an inbuilt HEPA (high efficiency particulate air) filter, to avoid particles simply being resuspended in the air rather than actually being removed. 

  1. Purifying the air

A certain level of pollution in the home is inevitable, but there are many air purifying methods that can be implemented to improve IAQ. 

Air purifiers

Effective air purifiers work by trapping and removing pollutants through drawing in dirty air, filtering it and releasing it back into the room. The best units have integrated fans to circulate clean air around the entire room, but more affordable portable air purifiers are just as effective. Just make sure to move it around occasionally rather than leave it in one spot. 

When selecting an air purifier there are a few things to consider. Choose a system with HEPA filter technology and high CADR (clean air delivery rate). This means the air will be filtered and redistributed more quickly. Be sure to select a purifier that has the UL 2998 validation badge; this ensures it won’t emit ozone, a harmful gas which negatively affects human health. 


Indoor plants are commonly thought to have air purifying effects, but a recent study revealed that a substantial difference to air quality would only be made by fitting between 10 and 1000 plants per square metre into a room. This is impossible to achieve, however there’s still plenty of reasons to incorporate plants into your home decor. 

Photo by Bellava G on Unsplash

They have numerous benefits on overall health, and some plants do still have a small positive impact on IAQ, such as snake plants and peace lilies. 

Style choices

There are a few cost-effective ways to improve your IAQ that will fit into every type of home. IKEA’s air purifying curtains are a neutral design that costs only £25; their mineral-based coating breaks down airborne odours and chemicals to help rid your home of excess pollution. 

Airlite’s range of environmentally friendly, air purifying paint is another cost-effective option that can be incorporated into every home. It can be applied both indoors and outdoors, and eliminates 99.9% of bacteria and mould, neutralises odours, and has been shown to reduce air pollution by 88.8%. 

6. Schools

Clean air – like clean water, shelter, and food – should be a human right, accessible to all. Poor IAQ has wide-reaching health effects, and children are particularly impacted. Children of all ages are susceptible to the effects of air pollution as their bodies and organs are still growing; long term exposure to poor IAQ can impact lung development and significantly worsen pre-existing conditions such as asthma and heart disease. 

The main issues with IAQ in schools

‘Air pollution is stunting our children’s brains, affecting their health in more ways than we suspected. But there are many straight-forward ways to reduce emissions of dangerous pollutants,’ says Dr Maria Neira – Director, Department of Public Health, Environmental and Social Determinants of Health at the World Health Organisation (WHO). Exposure can cause damage even before birth, harming normal lung development in the womb. The British Lung Foundation provides great in-depth information about why air pollution is so harmful to children.

According to WHO, over 90% of children worldwide breathe polluted air everyday. When we focus on London, tens of thousands of children are attending schools in areas where pollution levels exceed the legal recommendations. In urban environments like this, children spend a huge portion of their time at home, in schools, and in cars or on public transport. When they’re not indoors, they’re often subjected to highly polluted air on the roads. Research shows that children growing up in polluted areas have an average of 5% reduced lung capacity compared to those growing up in cleaner areas. 

The COVID-19 pandemic has shone a light on air quality and progress is certainly being made, but there’s still a lot of work to be done. The main pollutants (NO₂ and particulate matter) are unsafe at any level. Continued efforts must be made to reduce pollution levels in and around schools to improve the health of our children.

Read more about why we need to improve air quality both in and around schools here.

Why are children particularly vulnerable?

Traffic around schools

In London, around 50% of toxic emissions come from road transport, and this is made even worse by idling around schools. Air pollution from traffic is worst in the mornings, when school drop offs and rush hour coincide.

During these times, children and babies are the worst affected by this pollution as their breathing height is lower than that of most adults. Vehicle exhaust pipes tend to be around a metre above road level, while primary school children and pram seats are usually somewhere between 0.85m and 1.3m above the ground. This places them directly in line with exhaust fumes on a daily basis: they could be inhaling up to 60% more air pollution than adults during the school run. 

Diesel and petrol-engined vehicles are the single biggest contributors to air pollution on our roads. The sale of these vehicles will be banned in the UK from 2030, but for many children with worsening chronic conditions this is far too late. Jeffrey Young, founder of Camden Clean Air Initiative, said of the ban: ‘I wish it were sooner, we don’t need to use all the cars we do’. You can read more about the non-profit group and their aims in our interview with Jeffrey Young.

Poor air quality around schools is compounded by a lack of knowledge and understanding. It’s easy to assume that the most dangerous position for children is to be on the pavement, surrounded by exhaust fumes. However, exposure to toxic air is actually considerably higher inside cars. This is because cars are not built to be airtight, and when fans are on or windows are open, fumes from surrounding cars are sucked into the vehicle – and trapped there to be inhaled by passengers. 

Professor Sir David King says: ‘You may be driving a cleaner vehicle but your children are sitting in a box collecting toxic gases from all the vehicles around you.’ While smoking was banned in cars with a minor present back in 2015, little is being done to protect them from the toxic emissions from other vehicles. 

Banners by Clean Air for Dulwich and Mums for Lungs

Allergies and asthma

Asthma and allergies are very common among school children, and they can be significantly worsened by air pollution and poor IAQ. 

Little is known about airborne allergies compared to food allergies – many people are unaware they even have them. This is particularly dangerous when the affected in question is a school child; a paper from the European Academy of Allergology and Clinical Immunology from 2007 found that there’s a higher risk of anaphylaxis in school settings than elsewhere.

Airborne allergens include animal dander, dust mites, tree and grass pollen, mould, and feathers. 

Despite being a relatively common ailment, asthma can lead to hospitalisation in children. When managed with the right combination of medication, lifestyle, and environment, both asthma and allergies can be controlled. 

We spoke to Catherine Sutton – Director of Airborne Allergy Action last year, who says the link between asthma and airborne allergens is both misunderstood and under-communicated. This leads to aggravated symptoms among many children that could easily be prevented. Asthma is also worsened by poor IAQ, so it’s crucial to improve air quality in classrooms wherever possible. 

Read more about the connection between asthma and allergies in our conversation with Catherine Sutton here

Hay fever 

Hay fever, or allergic rhinitis, is another common allergy among school children. Evidence suggests that exposure to poor IAQ among children could increase the likelihood of developing hay fever. 

Recommendations for treating hay fever symptoms include choosing non-drowsy medication, regularly cleaning indoor environments, using natural and non-toxic cleaning products, and using HEPA filtered vacuum cleaners. 

What can we do?

Changing tides

The demand for cleaner air is growing, with non-profit groups like Camden Clean Air Initiative and Mums for Lungs working to improve air quality in and around London, and similar action being taken in cities across the world. 

There’s been an increase in activism among young people themselves. The current generation of young people is increasingly invested in sustainability, the environment, and the health impacts of pollution. Choked Up are a group of teenagers living in parts of London that are worst affected by air pollution, paying particular attention to the disproportionate effects faced by people of colour. We recently spoke with one of their founding members, Destiny Boka Batesa. 

Members of Choked Up

‘All four of us [founders] have grown up in areas that are badly affected by air pollution. And as a result, we’ve seen so many friends and family members be directly impacted by it. And these areas have high BAME and working class populations, meaning these groups are disproportionately affected. There’s a lack of government intervention in terms of taking care of these more vulnerable communities, and it’s something that we just couldn’t just stand by and watch anymore.’

You can read the full discussion here

Children and young people are, rightly, demanding better education about air quality, and legislative action to be taken to protect their health. In a Royal College of Paediatrics and Child Health report from 2020, young people were able to voice their concerns and have their opinions amplified through the hashtag #TeamCleanAir&Us: 

‘We want to know what the risks are from poor indoor air quality and what we can do to reduce them. Information needs to be scary enough for us to take notice but with enough information about what we can do that we feel we have some control and clear actions we can take.’

Campaigns like School Streets are already making positive changes to the quality of our air. The initiative is working to improve air quality by closing the roads surrounding selected schools to encourage walking and cycling, and reduce overall road traffic. A study measuring the impact of this campaign found a 23% reduction in nitrogen oxide during the morning drop off, and parents are overwhelmingly (81%) in support of the road closures. In a survey we carried out as part of our 2020 annual report, 96% of respondents said they supported the creation of Clean Air Zones. 

According to the Mums for Lungs website: ‘A School Streets trial at a primary school in Eltham resulted in a 54% reduction in cars driving to school, a 27% increase in cycling and 9% increase in scooting.’ The initiative is already making positive change through reducing traffic pollution, but also encouraging exercise. 

To learn more about the School Streets initiative, read our conversation with Jemima Hartshorn, founder of Mums for Lungs.

What can be done inside schools? 

As well as reducing air pollution from traffic, lots can be done inside the classroom to improve IAQ: 

  • Regularly clean dusty surfaces with damp clothes instead of dusters to prevent particles being spread around 
  • Invest in vacuums with HEPA filters 
  • Encourage walking, scooting or cycling to school 
  • Keep windows shut during busiest traffic periods if they face main roads, otherwise keep windows open as much as possible
  • Open internal doors to create a regular flow of air
  • Avoid outdoor activity during heavy traffic periods if playgrounds are in close proximity to a main road
  • Plant low-allergy hedges between roads and playgrounds to help mitigate pollution from traffic

What can be done by children and their guardians?

  • If possible, travel to school by walking, cycling or scooting: it’s much better for your health and the environment!
  • Encourage schools and local councils to take part in the School Streets initiative – Mums for Lungs have lots of resources to use
  • Never idle outside schools: switch off the engine when waiting, even if it’s a short period of time
  • Reduce the number of cars by carpooling with other children

What can be done by our communities?

  • Take alternative routes during rush hour to avoid passing schools 
  • Get involved and show support for School Streets and Clean Air Zones by writing to the school, the council or your local MP
  • For houses near schools, plant low-allergy green barriers such as hedges to help absorb pollutants and reduce traffic impacts

7. Workplaces

Why are healthy offices so important?

Good IAQ is essential for our health, and in workplaces poor air quality can severely impede employee productivity, satisfaction, and wellbeing. The COVID-19 pandemic has brought the health of our offices to the forefront of our attention, with IAQ being discussed more than ever before. 

Many office workers suffer from Sick Building Syndrome (SBS), a phenomenon with undefined causes, but it’s often attributed to indoor spaces with poor IAQ. The first signs of this are multiple team members complaining about similar symptoms; these symptoms most often include headaches, drowsiness, skin irritation, dizziness and lack of focus. Symptoms usually increase in the office and are alleviated once employees leave the building. 

Unhealthy employees can have a huge impact on a business, with SBS costing the British economy an estimated £24.6 million in lost work days every year.

Defining the exact causes of SBS is challenging, but key air quality factors play a part, such as:

  • Inadequate ventilation 
  • Lack of air change
  • Low humidity
  • High or constantly changing temperatures
  • Airborne pollutants, such as dust, carpet fibres or fungal spores
  • Use of toxic cleaning chemicals
  • Poor lighting that causes glare or flicker on screens

A combination of these factors will undoubtedly contribute to poor IAQ, negatively impacting employee health and productivity. 

In a survey conducted as part of our 2020 annual report, 53% of respondents reported that they would consider not working for a company if they couldn’t prove the quality of their indoor air. There will soon be a notable divide between companies with high-quality work spaces, focusing on the health of their employees and their environmental impact, and those who are not making these factors a priority. 

As the health of our indoor environments becomes increasingly important, employers and landlords have a responsibility to be transparent about the quality of a building’s indoor air, as well as empowering their employees to access this information themselves. Likewise, employees and tenants have a responsibility to use this knowledge and data to use a space wisely and do their bit to improve the IAQ in a workplace. 

If you want to learn more about how interest in IAQ has evolved in recent years, read our interview with Chris Rush, Air Quality Group Lead at Hoare Lea and committee member of the Institute of Air Quality Management.

Why is IAQ a problem in offices?

In recent years, commercial buildings – such as offices – have become increasingly airtight in the name of energy efficiency and heat conservation. This leads to worse IAQ as pollutants are often trapped indoors, high CO₂ levels from large populations of employees in one space, and issues with humidity. 

Humidity levels are often too low in offices (below the optimal range of 40-60%), leading to dry skin and lips as well as scratchy throats and noses. Ventilation plays a huge part in maintaining optimal humidity levels, as well as regularly clearing indoor pollutants and replacing a buildup of CO₂ with fresh oxygen. The American Society of Heating, Refrigeration and Air-Conditioning Engineers (ASHRAE) states that 1000ppm is the point at which a room begins to feel stuffy, and office levels regularly exceed this. 

Simply opening windows is often one of the easiest and most effective ways to improve IAQ, but in many commercial buildings this isn’t always possible. Windows often have safety latches that prevent them from opening fully, and expansive floor plans mean that employees positioned in the centre don’t actually benefit from fresh air coming in. On top of this, it’s worth noting that many commercial buildings are positioned in city centres and on main roads – so the outdoor air quality is actually far from fresh. 

Employers may be reluctant to encourage open windows for a range of reasons:

  • Energy efficiency concerns
  • Cost concerns
  • They allow traffic noise, rain and insects to enter
  • The can become liable to any injuries or people falling out
  • May cause internal conflicts between employees 

Poor IAQ in offices can result in employee illness, as well as promoting mould growth throughout the building. Air conditioning units (and lack of) can also create an increase in humidity, air that’s too dry, or simply moving pollutants around the air rather than removing them. VOCs are often generated in offices by: 

  • Toxic cleaning products
  • Solvents
  • Dust
  • Carpet fibres
  • Furniture
  • Outdoor traffic pollution
  • Photocopiers and printers
  • Building materials

Too often, companies pay great attention to factors such as their office layout and perks such as free lunch and coffee, without properly considering their IAQ. We recently spoke to Jeroen van Straten, Founder of IndoorCare, who told us:

‘We have assessed many offices over the years, and the vast majority of the time the inside air is unhealthy, regardless of whether the building is old or new, modern looking or not. Unfortunately, indoor air quality is simply not taken care of.’ 

With the COVID-19 pandemic shining a light on the importance of good IAQ, employers must improve the quality of their indoor air as a matter of urgency, and communicate its importance to their employees.

How has COVID-19 changed the workplace?

The outbreak of the COVID-19 virus altered almost every part of our lives, with the way we work being one of them. In many countries, millions of office workers went fully remote practically overnight. 

This shift has brought many positive, much-needed changes to daily working – from improved digital capabilities to huge cost savings and having more flexibility over their time. 

There’s potential for employers to make significant changes to reduce their bottom line as well. By adopting a hybrid working model and reducing the number of people physically in the office, companies can downsize to smaller office spaces and embrace a wider geographical pool of employees. 

Another silver lining of the COVID-19 pandemic is that it has also forced IAQ into general conversation: the quality of our air is no longer reserved for industry experts. Companies now have to re-evaluate the health of their buildings, and find ways of communicating this data to their employees. 

If organisations are keen to get their workers back into the office, there needs to be some assurance that this environment will be healthier than their home. Without this information, employees have no incentive to return to stuffy, humid office buildings. Workers have the right to demand more from their offices and work in spaces that are safe, healthy, and conducive to productivity.

We recently explored how safe it actually is to return to offices in London, read the article here.

How can we make offices healthier?

IAQ can easily be improved in workplaces through a range of low- and higher-cost changes: all of which will positively impact employee wellbeing, satisfaction and productivity. 

  1. Ventilation

Ensuring adequate ventilation is the first step to making positive changes to the quality of air in any workplace. It’s a crucial way of preventing SBS, as well as reducing the risk of COVID-19 transmission. As outlined on the UK government website, ventilation is a key aspect of making any building COVID-secure. 

Opening windows and making use of built-in features like trickle vents are often effective methods of ventilating an indoor space, however, this isn’t always possible. Using mechanical ventilation systems like extractor fans in bathrooms or kitchen areas will clear any pollutants from beauty products or food preparation. 

It’s also worth noting that simply opening an internal door during a meeting will make a significant difference to the flow of air, and prevent small rooms from becoming too stuffy when heavily occupied. 

  1. Air filtration

Filtering the air is another effective way to remove pollutants that will inevitably build up during the work day. Air purifiers fitted with a HEPA (High Efficiency Particulate Air) filter work by capturing dust, allergen particles, and some VOCs from the air, improving IAQ significantly. 

For some buildings, filters can be built into the existing or new air conditioning system, ensuring that fresh air is evenly distributed throughout the building. This may not always be appropriate, in which case portable air purifiers are an efficient way of improving air quality: just make sure they aren’t constantly in one spot. When selecting an air purification system, ensure you select one with a high CADR (clean air delivery rate): the number indicates how quickly the unit will filter air, so go high. It’s also important to select a unit that is UL-2998 standard compliant, as these units will not emit ozone. 

Particle filters integrated in ventilation systems must be the appropriate grade, in line with external particulate levels in the building’s location. Additionally, they must be maintained properly to work effectively. 

Another small way of filtering the air in a workplace is incorporating plants through living walls or placing them around the office. Although they won’t make nearly as much difference as an air purifier, they are a great addition to a space as they boost the wellbeing employees by absorbing excess noise. Certain plants, such as snake plants, spider plants and peace lilies, are particularly good for air quality, so it’s worth selecting these. Studies have found that when employees worked in environments with natural elements, such as plants, their wellbeing was 13% higher, and their productivity increased by 15%

  1. Environmental monitoring

Installing air quality sensors is a great way to actually understand the health of your indoor environment, and which areas need rectifying. IAQ sensors will monitor key factors of your air quality, such as:

  • Temperature
  • Humidity
  • CO₂ (carbon dioxide)
  • CO (carbon monoxide)
  • NO₂ (nitrogen dioxide)
  • O3 (atmospheric ozone)
  • VOCs (volatile organic compounds)
  • PM2.5 (fine particulate matter)

There is extensive information available to ensure the sensors you select are accurate and effective; this study outlines the performance of several low cost sensors. You can also seek third-party accreditation to certify the quality of your indoor air, such as our certification: the AirScore.

  1. Occupancy and capacity monitoring

Occupancy and capacity monitoring through sensors is the most valuable way of understanding how office space is actually being used. It’s a hugely important part of creating a healthy work environment, as building managers can accurately track factors such as real-time people count and density in any area. By understanding the usage patterns across your entire building, action can be taken to avoid overcrowding, ensuring these rooms do not become humid and stuffy. 

  1. Raising awareness

Although awareness of IAQ has increased in recent years, it’s crucial to ensure quality of air becomes a standard topic of discussion in our workplaces. It’s not just facility managers who need to be aware of IAQ, this should extend to building owners, employers and employees. This way, everyone will have a better understanding of their daily environment, as well as the changes they can make to improve poor air quality. 

When steps are taken to improve IAQ, a positive working environment can be achieved for everyone involved: resulting in reduced sick days and a more productive workforce. 

Implementing air quality sensors with data that can be easily accessed and interpreted will communicate to employees that their health is a priority, and steps are being taken to keep them safe. Additionally, raising awareness of air quality in your workplace will encourage all workers not to use toxic products within confined spaces, and keep doors and windows open where possible. 

  1. Control indoor pollution sources

While removing all indoor pollutants is impossible, it’s important to aim to control sources of pollution as much as possible. 

VOCs include a range of chemicals that can be harmful to our health, and are emitted by some furniture, cleaning products, and sealants. Where possible, companies should select furniture and flooring that emit fewer harmful VOCs. 

Another office staple, the printer and photocopier, can be detrimental to employee health as they produce dangerous levels of ultrafine particles (UFPs) and ozone. It’s wise to keep these units in a well-ventilated room away from desks to avoid a build-up of these harmful pollutants. 

Cleaning surfaces regularly with a damp cloth is an effective way of removing any pollutants that have become attached to desks and worktops. However, it’s crucial to select natural, non-toxic products that do not release dangerous chemicals, as these products could do more harm than good. 

Carpets and rugs should be vacuumed at least once or twice a week, and it’s good to invest in a vacuum cleaner equipped with a HEPA filter to properly remove pollutants from these surfaces, rather than just redistribute them into the air. 
If you’re interested in learning more, read our conversation with Ruth Duston OBE as she explores how the pandemic has changed London’s workforce.

8. The future of IAQ

Growing awareness

The COVID-19 pandemic has kickstarted a conversation about the health of our indoor spaces and, specifically, the quality of our air. Our society is increasingly aware of the importance of hygiene, personal space, and ventilation. In a survey we conducted in 2020, respondents reported a 57% increase in awareness about IAQ, showing the topic is really gaining traction. 

This awareness will only continue to grow as air quality data becomes more readily available. Currently, fewer than 40% of the world’s governments share real-time air quality data publicly – meaning that in over half of the countries globally, residents have no easy access to the quality of the air they breathe. 

Many employers and landlords are beginning to implement real-time air quality monitoring in their commercial buildings and show a real commitment to their IAQ. While there is huge growth to be made in this area, as IAQ monitoring becomes more common, there will be an increased pressure placed on those who are falling behind. 

Additionally, there has been a significant increase in air-positive alternatives, such as the use of electric cars in place of petrol and diesel vehicles. 2020 saw the biggest increase yet in electric car purchases, with the growth rate increasing by 66% compared to 2019. It’s small lifestyle changes like this that will gradually have a huge impact on the quality of our indoor and outdoor air. 


The tides on IAQ are slowly changing. Both the general public and country leaders are realising poor air quality is affecting us all, both inside and outside, and significant change must be enacted. 

At the start of 2021, the UK Government set out ‘rigorous new targets for green building revolution’. The updated Future Homes Standard outlines plans to improve the energy performance of homes; targets state that all new homes built after 2025 will produce between 75% and 80% lower emissions than those under current regulations. To ensure this is possible, new homes are expected to produce 31% lower emissions from 2021. Regulations will also apply to existing homes by the way of improvements to extensions, making these buildings more energy efficient. 

Similarly, the Future Buildings Standard of 2021 focuses on improving the health and energy efficiency of non-domestic buildings, such as offices and gyms. Targets include a ban on all boilers powered by fossil fuels from 2025 and a significant reduction of carbon emission production. In the wake of COVID-19, the regulations also outline that ventilation rates in these spaces must be 50% higher than the minimum standard for other buildings. There will also be measures in place to mitigate overheating. As well as reducing the risk of disease transmission, this will have a positive impact on the overall wellbeing and productivity of occupants in these non-domestic spaces. 

Francesca Brady, the CEO of AirRated, recently commented on these regulations in The Times: ‘The guidance within this new proposal is pivotal as it considers unpredictable changing climates, carbon net-zero goals and occupant health.’

Many other regulatory changes have been announced, such as the cessation of coal use. Coal consumption is incredibly carbon-intensive and contributes at large to levels of air pollution: as of 2024 it will no longer be used to generate electricity in the UK. 

At a local level, many UK councils are implementing measures such as Clean Air Zones, whereby petrol and diesel vehicles will either be prohibited from driving in certain areas, or will be charged a fee to enter the zone. 

To learn more about the regulations and standards relating to air quality, NICE (National Institute for Health and Care Excellence) provides fantastic, in depth resources

These recent developments in the fight for cleaner air are worth celebrating, and many action groups are making great waves in their work by demanding change and bringing attention to the issue. However, many are calling for more widespread legislation change, such as an updated version of the current Clean Air Act of 1993. A staggering 99% of London currently exceeds legal limits of PM2.5, as outlined by the World Health Organisation.

On this topic, Choked Up co-founder Destiny Boka-Batesa says: ‘The Clean Air Act in question right now hasn’t been updated since the 90s and the problem with that is, we’re now in 2021. The issues that people faced in the 90s are completely different to the issues we have now. Existing legislation doesn’t cater to communities like mine. We need something solid, something that will actually be actioned to improve air quality in all areas across the UK, but more specifically for those who are worst affected by air pollution.’ Read our full conversation with Destiny Boka-Batesa here

The rise of ESG

ESG (environmental, social, and governance criteria) is becoming an increasingly important way of how businesses operate, as well as influencing investment decisions. ESG encompasses many challenges faced across the world, such as air pollution and sustainability, and other crucial focus areas such as racial inequality and exploitative working conditions. 

As awareness of ESG areas increases, businesses are under increasing pressure to show they are committed to making positive changes. Large corporations in particular have the power to make a meaningful difference by addressing ESG factors and increasing their commitment to sustainability, creating a new and improved industry standard. 

Extensive research has shown that ESG factors align with better financial performance; by looking at ESG issues investors are able to pinpoint companies that are likely to succeed, versus those that will likely come up against challenges in the near future. 

Discussing the growing focus on ESG, Michael Grant, COO at Metrikus said: ‘ESG is becoming ever more important, but it’s impossible for companies to truly show their ESG commitments without monitoring their indoor air quality and energy and water usage.’

Aspects like monitoring and actively improving IAQ is an easily demonstrated step to creating a healthier indoor space, as well as minimising environmental impacts. Creating healthier buildings will not only help improve employee output, but will contribute towards creating a better standard of living for future generations. 

Data will play a pivotal role in demonstrating a commitment to ESG factors, and it’s essential that businesses implement accurate environmental monitoring throughout their buildings to demonstrate these improvements in an accessible way. 

Addressing environmental, social, and governance factors is crucial in tackling major challenges, and companies that do so will play an integral role in creating a healthier, more sustainable future. 

Better indoor air quality?

Will greater awareness and stricter regulations improver our indoor air quality? Although it’s impossible to tell yet, conversations surrounding IAQ and air pollution overall are moving in a positive direction. The COVID-19 pandemic has pushed IAQ into public consciousness, and people are far more invested in the health of their indoor spaces as a result. 

As 2021 progresses, workers will begin to return to the office and will demand more from their employers regarding their own health and safety. Companies will be competing to acquire and retain talent, and with remote working now a viable possibility for many, employers must demonstrate they are committed to creating healthy, safe, productive spaces – otherwise talent will simply go elsewhere. In a survey we conducted in 2020, 67% of respondents said they would consider paying to have real-time IAQ data and alerts in their business properties. Improving IAQ is no longer a choice, it’s a necessity. 

Likewise, the current generation of schoolchildren has faced over a year of disruption to their education. Getting these children back into schools is a priority, but we must do so safely. The pandemic has forced many conversations about air quality in and around our schools, and campaigning groups like Mums for Lungs and Choked Up are making great strides in demanding healthier environments for our children. 

The CEO here at AirRated, Francesca Brady, discussed her predictions for the future of air quality: ‘2020 has seen the general public become more informed about air quality, but it’s come at a devastating cost: between COVID-19 and wildfires: our learning curve has been a steep one. However,’ Francesca writes, ‘I think that people will continue to become more empowered and informed about air quality: as occupier expectation changes, this will put pressure on developers for healthier buildings – it’s a very positive cycle.’

Of course, there are positive changes to celebrate: 

  • Studies show that a switch to a plant-based diet could remove up to 8 billion tonnes of CO₂ emissions by 2050
  • Companies like Ecosia, the search engine, have planted over 100 million trees: this will remove up to 1,771 tonnes of CO₂ every day
  • New research shows that 54 major global cities are on track to keep global heating below 1.5°C

Changes like this will positively impact air quality everywhere, but we all have the ability to make smaller, individual changes; this will be vital in the fight against climate change, and the mission to improve air quality in our own homes, workplaces, and public buildings.