Research links air pollution to lung cancer and heart disease. Here's how to prevent it. Photo / 123rf
You might not realise it, but the air you breathe outside, and in your home, could be shortening your life.
A new report from scientists at Imperial College London, which examined evidence from more than 35,000 studies, has linked exposure to harmful pollutants such as nitrogen dioxide and tiny particles or droplets in the air known as PM2.5 to the risk of many different diseases over the course of a lifetime.
The report links air pollution to lung cancer and cardiovascular disease, but it also shows that breathing poor quality air can stunt lung growth in children, in some cases triggering the onset of asthma as well as affecting their cognitive abilities.
Pregnant women who are exposed to chronic air pollution are at a greater risk of miscarriages, while it can impact the unborn baby.
“It’s terrifying,” says Philippe Wilson, Professor of One Health at Nottingham Trent University. “Here we’re seeing air pollution associated with diseases at every stage of life. That goes from things like fetal development before birth to common illnesses like cancer and mental health problems.”
But can we trust that this research is accurate?
“What’s particularly impressive with this report is that they actually carry out a proper systematic review, which is the highest level of research accuracy,” says Wilson. “That hasn’t really been done to such a breadth in this field before.”
So how can you reduce the amount of pollution you are being exposed to? We asked the experts, and they suggested the following six ways.
The Department for Environment Food & Rural Affairs (Defra) produces a daily air-quality index, which provides regulated measures of the concentrations of five common pollutants – nitrogen dioxide, sulphur dioxide, ozone, PM2.5 and inhalable particulate matter (PM10) – across the UK.
“It’s combined into a one to 10 scaling system so it’s easy to interpret,” says Samuel White, a researcher at Nottingham Trent University. “And it also includes forecasting functions, so you can see where the pollution is likely to be. So for example if it’s looking like a high pollution day in your area, maybe you exercise in an indoor gym rather than outside.”
Suzanne Bartington, an environmental health researcher at the University of Birmingham, says that this information is particularly valuable to the people who are most vulnerable to air pollution, for example those with existing heart and lung conditions, such as severe asthma or chronic pulmonary disease.
“For those people, the emphasis is on being aware of when air quality is going to be particularly poor and following the health advice such as avoiding strenuous activity on those days,” she says.
“It’s also important to point out that poor air is not just applicable to urban areas, there are air-quality issues in rural areas with ozone, particularly in the spring and summer. Pollution can also move across boundaries, so some of our pollution here in England comes from continental Europe.”
In the UK, it is estimated that we spend more than 80 per cent of our time indoors so making sure that the air quality in your home is reasonable is extremely important.
As well as airborne viruses, Bartington points out that indoor air can be polluted by chemicals known as volatile organic compounds, which are present within many common cleaning products, as well as shop-bought incense and scented candles.
Newly purchased home furnishings, such as sofas or tables, have often been treated with chemicals to make them look fresh.
“We know that there are health effects associated with certain doses of those chemicals,” says Bartington. “Anything treated with chemicals will have a certain air-quality footprint to it. And then when you disturb the indoor environment, for example by vacuuming, you will release particles into the air as well.”
As well as ventilating your home by opening windows and doors after cleaning, air purifiers are thought to be one of the best ways of trying to keep your indoor air as clean as possible.
However, the air-cleaning device market is currently unregulated in the UK and not all air purifiers are equivalent. Those that use ionising or electrostatic precipitation technologies may actually be unsafe because they generate nitrogen oxides and ozone through their operation.
Wilson recommends buying a purifier with a high-efficiency particulate absorbing (HEPA) filter.
“HEPA filters are very fine grain, and they tend to remove all sorts of things, including viral particles,” he says. “But you have to make sure the filter gets changed, cleaned and monitored, because a lot of people have devices with HEPA filters that just sit there for years and years, and that’s no good.”
Francis Pope, an environmental sciences professor at the University of Birmingham says that air quality during the darker hours of the day is likely to be lower.
This is because as the temperature drops during the nighttime hours, the atmosphere traps car emissions, CO2, and other pollutants down near the ground.
“If possible, exercise during the day,” he says. “That’s easier at this time of year, but it means that during the winter, your time for outdoor exercise is more limited. If you can avoid running close to a busy road, that will also reduce the amount of pollution you are exposed to.”
There are a growing number of monitors and sensors coming on to the market providing homeowners with a relatively cheap way of assessing whether the air in different parts of their house needs cleaning or ventilating.
A 2021 report found that carbon dioxide concentrations consistently above 1500 parts per million suggests that the ventilation is poor and that air cleaning might be beneficial.
White says that some of the newer sensors can even measure the levels of tiny particles of pollution within the home.
“You’ll find even some of the HEPA filters will have built-in sensors,” he says. “So if levels come up to what the purifier considers more of a higher burden of particulate matter in that room, it will automatically kick things up a gear.”
Using an extractor fan in the kitchen and bathroom when cooking or cleaning can mitigate the levels of chemical pollutants in the air within the home, but if you are thinking of getting a new stove, experts recommend switching to a newer induction or electric version or a gas one, as these help to avert indoor air pollution.
“We know that anything with a combustion source, so gas in particular, will produce pollutants like nitrogen dioxide, and particles as well,” says Bartington.
“And you get very high spikes during cooking. We’ve published some data looking at household cooking, and you’re getting levels over a short period of time, which exceed those in urban city centres. But a lot depends on whether people are using their extractor fans.
Another option is to keep the kitchen well-ventilated through leaving windows open, although the benefits of this are mitigated if the Defra air-quality index suggests that outside pollution is particularly bad. Bartington suggests opening a window on a side of the house that is away from the road, if possible.
Experts recommend walking or cycling as much as you can because evidence is increasingly showing that the air quality in indoor environments on trains or buses can actually be worse than being outside next to the road.
Bartington says that while you might be exposed to vehicle emissions from passing cars, this is counterbalanced by the benefits of exercise on your immune system, which makes the body more able to handle the impact of polluted air.
One government report found that the amount of pollution experienced by passengers on trains powered by diesel engines is 13 times higher than on one of central London’s busiest roads. Passengers are more exposed to the fumes when sitting in rear rather than front carriages, due to how the exhaust is drawn into the train’s air-conditioning system.
In your own car, you can reduce how polluted the air is by switching on the extractor fan.
However, if you are driving on a warm day, it seems that keeping your vehicle cool through circulated air is better than opening a window.
“There’s evidence that if you recirculate the air in the vehicle and close the windows, you’re less likely to be sucking in external air in a heavily polluted environment,” says Bartington.