When people think about air pollution, images of smoke, traffic fumes or dust likely come to mind. However many don’t realise the air they breathe inside their homes could actually be as damaging as pollutants found in the outside environment.
New research conducted by the Washington State University revealed that “surprisingly high” levels of pollutants including formaldehyde and mercury were detected inside homes which were carefully monitored as part of the study, with harmful pollutants found to spike at certain times of the day and increase as temperatures rise.
The study, published in the Building and Environment Journal, shows that air pollution found both in and outside the home can significantly impact the health of the heart and lungs, as well as neurological health. Governments around the world have increased regulation of outdoor air pollution over the past four decades, but there’s currently little regulation when it comes to the quality of air inside homes.
“People think of air pollution as an outdoor problem, but they fail to recognise that they’re exposing themselves to much higher emission rates inside their homes,” lead researcher Tom Jobson said in a statement.
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The study found that harmful emissions come from a variety of sources in and around the house including building materials, furniture, household chemical products and even from daily activities such as cooking. One of the most effective ways to clear harmful chemicals is with ventilation but houses are increasingly being built more airtight to reduce energy use. According to researchers, this could inadvertently be worsening the pollution issue as it could limit the flow of fresh air.
Researchers analysed a variety of homes to reflect typical housing styles across the US. Levels of formaldehyde – which can irritate the eyes, nose, throat and increase the risk of asthma – increased when temperatures inside the home rose.
“As a home gets hotter, there is a lot more formaldehyde in the home,” Jobson explained. “The materials are hotter and they off-gas at higher rates.”
There are also concerns that heatwaves and changes to climate could further impact indoor air quality.
“As people ride out a hot summer without air conditioning, they’re going to be exposed to much higher concentrations of pollutants inside,” Jobson said.
Pollution levels also vary throughout the day and were highest in the afternoon but lowest in the morning. In the past, manufacturers and builders believed pollutants stayed the same at all times. This influenced decisions they made when considering emissions from their materials but may not have realised the true amount of pollution people were exposed to in their homes because of their material choices.
Of particular concern to researchers was gypsum wallboard – a popular material used as drywall that’s made from waste products of the coal industry. Researchers found that when a piece of gypsum wallboard was heated in the laboratory, it measured high levels of formaldehyde and possibly mercury.Mercury can cause irreversible damage to the nervous, digestive and immune systems and irritate the lungs, eyes and even kidneys.
“Exposure to these chemicals impacts people’s ability to think and learn,” Jobson said, noting the importance of people having knowledge of the risks. “Opening a window is a good thing.”
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Researchers are now investigating new ways to reduce exposure to indoor air pollutants such as using green building materials when building or renovating homes.
“We have to balance making more energy efficient homes with protecting our health and cognitive function,” Jobson said.