Nearly seven million people die prematurely each year because of ambient and household air pollution, according to the World Health Organization (WHO). Moreover, studies have shown a direct correlation between classroom air quality and children’s performance in school. Finally, according to WHO, household air pollution exposure contributes to non-communicable diseases, including increased risk of illness and death from stroke, ischaemic heart disease, chronic obstructive pulmonary disease and lung cancer.

However, most of WHO’s work on indoor air pollution has been focused on dirty wood, coal and biomass stove use in developing countries. Less studied are the health risks associated with poor ventilation in modern buildings – ranging from virus transmission to high CO2 levels and the outgassing of chemicals like formaldehyde from building materials and furnishings.

With these challenges in mind, the WHO’s European Region, the Swiss government and the Geneva Health Forum are partnering on a first-ever Indoor Air Conference on September 20 in Bern, Switzerland. The day-long event will bring together diverse experts to discuss indoor air pollution, why it needs monitoring, and how to improve indoor air in older buildings.

COVID triggered a re-evaluation of indoor air pollution risks

“We spend around 80% or 90% of our time indoors, so what we are exposed to there has an impact,” said Catherine Noakes, of lifestyle patterns in urban settings of developed countries.  A professor of Environmental Engineering for Buildings at the University of Leeds, she will moderate the event.

The COVID-19 pandemic underscored the significance of proper ventilation in reducing the spread of viruses that cause respiratory illnesses; higher exchange rates reduced indoor virus transmission, WHO documented in a milestone set of guidelines for schools, homes and offices, issued  during the pandemic.

Chemical pollutants indoors getting more attention

But the risks are not limited to infectious diseases. In the absence of proper ventilation, even cooking on a modern gas stove can lead to excessive exposures of fine particulates and oxides of nitrogen (NOx), which have been linked to childhood asthma. Indoor dampness and mold also are associated with increased risks of asthma, chronic respiratory illnesses and allergic reactions, according to WHO.

Chronic exposure to toxic cleaning products and carcinogenic chemicals such as formaldehyde used in particleboard, glues and resins of many modern furniture and building materials can lead to increased risks of chronic health conditions over time.

CO2 and cognitive performance

A number of recent studies, including one published by a team of Harvard researchers, has documented how higher levels of CO2 indoors are associated with reduced cognitive performance. The team compared the performance of student volunteers engaged in a game simulation, in settings with indoor CO2 levels of 600 1000 and 2,500 parts per million (ppm). Outdoor levels typically range from 300-400 ppm although they can rise as high as 900 ppm in cities.  The researchers found a slight drop in mental performance at CO2 concentrations of 1,000 ppm, and a significantly larger decline at 2500 ppm.

Finally, in heavily polluted cities, outdoor air pollution can seep into buildings and cause harm – from allergies to respiratory conditions or, as WHO documented, even death.

‘No magic bullet’

Unfortunately, there “is no single magic bullet” that can solve the indoor air pollution crisis, Noakes said. However, there are several recommendations – many of them inexpensive and applicable in the Global North and South.

“There are lots of different strategies,” Noakes said. “You don’t need an expensive ventilation system in every building.”

First, the best way to remove pollutants is to provide fresh air. Ventilation needs to be integrated into the design of a building – whether that includes windows that open or a sophisticated system of mechanical ventilation and air purification. In highly polluted cities, indoor air purification systems are increasingly a part of the equation, removing harmful particulates from, breaking down volatile organic compounds and neutralizing bad smells inside homes and office facilities.

According to Noakes, part of the solution is also building awareness so that people can catch pollution before it causes lasting harm.

A study by the Royal Academy of Engineering showed that improving ventilation could reduce long-range aerosol transmission of diseases by about 50%. Improving ventilation and ensuring good air quality could also enhance productivity by around 1-4%.

Climate change vs. indoor air pollution

There is, however, a tension today between trying to save energy and reduce the impact on climate change and the environment by improving insulation and air tightness of a home or office and ensuring its proper ventilation, explained Noakes. While very well insulated homes and office buildings reduce greenhouse gas emissions, it also means the spaces cannot “breathe.”  Without advanced mechanical ventilation systems and proper air filtration, harmful chemicals, viruses and CO2 may all build up.

“On the one hand, the more we move to reduce fossil fuels, take gas, oil and solid fuels for heating and cooking out of the home, that is a good thing,” Noakes said. “On the other hand, some actions around net zero are potentially making indoor environments worse by sealing pollutants in buildings.”

‘We should be breathing good quality air’

Noakes said she hoped this event would spark discussion around the topic and bring about new solutions.

“If you go back 100 or 150 years, we had the same discussions around clean water, and now it is just accepted that everyone should have clean water. It should be the same thing with air,” Noakes said.

She acknowledged that there are costs associated with improving air quality, and those need to be considered in the equation. But ultimately there is no downside to having clean air.

“We all breathe continuously,” she concluded. “We should be breathing good quality air.”

For more information or to register for the First WHO/Europe Indoor Air​ Conference, click here.

Image Credits: Pelle Sten/Flickr, US Centers for Disease Control, DMW/Flickr, Geneva Health Forum , Rachel Lovinger/Flickr.