As we spend more time working from home, understanding the factors that affect air quality within our houses is increasingly important.
You could be exposed to unhealthy levels of air pollution inside your own home even when outdoor air quality is good, a new study has revealed.
Researchers at the University of Birmingham in the UK measured particulate matter (PM) pollution in three homes over two weeks. They found that pollution levels in each house were higher and more variable than those outdoors. One home exceeded World Health Organisation PM2.5 limits on nine of the 14 days.
“Our study shows the need to monitor indoor air pollution, as people can have unhealthy air at home even if outdoor air is good,” says co-author and Clean Air Fellow Catrin Rathbone.
“PM levels varied significantly between homes, indicating that monitoring just one location isn’t enough.
What causes high levels of air pollution in homes?
Understanding what increases air pollution in homes is key to helping reduce your exposure.
“With more time spent working from home, understanding the factors that affect air quality within households is increasingly important,” emphasises co-author and Clean Air Fellow Owain Rose.
“The methods we used accurately modelled indoor PM levels, helping to improve exposure estimates at a low cost.”
The researchers identified several different factors that contribute to levels of particulate pollution in indoor spaces, both inside and outside. Indoors, increased movement of people inside the home caused higher levels of larger PM10 – particles 10 micrometres or less in diameter. Activities like cooking, smoking and heating are major sources of PM2.5 – smaller particles of 2.5 micrometres or less in diameter.
Buildings can’t filter outdoor air, so particulate pollution comes in through open windows, doors and even gaps in the facade. A nearby kitchen vent from a restaurant, for example, had a significant impact on the levels inside one of the homes.
What can you do to cut indoor air pollution?
We can’t avoid being in our homes, of course, but there are a few things you can do to combat pollution levels indoors. Some of them seem like no-brainers but could significantly cut down on the pollutants you are exposed to.
Vacuum your carpets and rugs frequently
This can be one of the best ways to get rid of polluting particles that linger in your carpets and soft furnishings. Use a good-quality vacuum to pick up the most particles and ensure they don’t leak right back out into the air from the machine.
If you really want to cut down on the polluting particles in your home or suffer from allergies, a wood floor is much easier to clean. Not wearing shoes indoors, washing your bedding regularly and shaking non-washable items clean outside can also help keep your house free of polluting particles.
Open your windows – but be strategic
If the air quality is better outside, opening your windows could be a simple fix to remove polluting particles. But with outdoor sources also increasing indoor pollution, you need to be smart about it.
If you live near a busy road, don’t open windows during peak traffic times, for example. The Building Engineering Services Association (BESA) recommends you monitor your local pollution levels and then keep windows open for longer on days when pollution levels are lower and for less time when pollution levels are higher.
For example, residents of one home in the study that recorded lower levels of indoor pollution overall were more likely to open a window in the bedroom during the day.
Swap out your gas cooker
All three of the homes in the study had gas central heating and a gas-fired hob and oven. Opting for an electric stove instead could cut indoor pollution.
Gas cookers emit other harmful pollutants aside from PM including nitrogen dioxide (NO2). Last year, a team at the University Jaume I’s School of Health Sciences in Spain estimated that they contribute to the early death of around 40,000 Europeans each year.
Previous studies have found that using an electric stove instead could cut average daily indoor NO2 pollution by 56 per cent.
The European Public Health Alliance has urged EU lawmakers to phase out gas cookers through emissions limits. But getting rid of them can be expensive and the EPHA has also called for the introduction of financial incentives for switching to cleaner options.
Use your extractor fan
Using a cooker hood and extractor fan could also help get rid of the grease, smoke, smells and moisture left in the air after you cook. Turn them on while you are cooking and leave them on afterwards to clear the air.
One of the three homes in the University of Birmingham study which recorded lower levels of pollution overall regularly used an extractor fan when cooking.
