Smoke from wildfires in Canada last week left millions of people across the United States and Canada experiencing some of the worst air quality in the world. Cities and towns with dense orange smoke.
In New York, residents are urged to stay indoors and wear high-grade face masks when going out.
It has been common knowledge for some time that exposure to heavy air pollution is harmful to health, especially for people with existing respiratory problems. But recent studies have made it clear that poor air quality isn’t just a problem for the lungs. Pollutant particles – from wildfire smoke, car exhaust, truck tires or plastic waste – can cause damage throughout the body.
Here’s what we know from recent science about air pollution and health.
Air pollution affects not only the lungs but the whole body
Poor air quality has long been linked to respiratory problems such as asthma and reduced lung function. But in recent years, research has shown that the damage caused by a certain pollution – fine dust – can be carried in the body.
“If the particles in the air are small enough, they will penetrate into the lungs and settle there in the air sacs,” he says. Annette Peters Helmholtz University in Munich, Germany.
Such deposits stimulate the activity of macrophages White blood cells remove bacteria and other microorganisms from the body. These macrophages recruit other immune cells from other parts of the body, causing inflammation and cell damage in the process. “There is a systemic signal that helps clear the lungs, but it transmits the negative effects of air pollution to the whole body,” says Peters.
We are still learning how harmful airborne plastic is.
Airborne microplastics are a major component of pollution that affects human health, but little is known about the effects of plastic particles on the human body. Most of the research comes from laboratory experiments on cells or mice, he says Stephanie Wright at Imperial College London, and these studies rely on commercially available polystyrene spheres to act as microplastic samples. “We don’t know how this adds up to the types of microplastics we know are in the air,” she says.
There are some suggestions that particle shape may play an important role. Threads of fibersFor example, it can be very difficult to clean the macrophages, which causes a lot of inflammation in the body. But more work is needed to understand what kinds of plastic particles, including fibers, are in the air around us before we can understand the extent of the threat they pose. “If you want to understand the level of risk, you need both exposure and risk data,” says Wright.
Air pollution can make hay fever and allergies worse
Living in the city makes sneezing worse in the summer, and recent studies have suggested that air pollution can make hay fever and other allergies worse.
A A recent study In the year It reviewed 36,145 symptoms reported by people with hay fever in the UK between 2016 and 2020. People living in cities have experienced hay fever symptoms such as runny nose, sore eyes and shortness of breath. areas.
People who live in cities are more likely to experience worse symptoms when ozone levels are high, the researchers found. Ground-level ozone pollution is created when sunlight interacts with hydrocarbons such as methane and nitrogen oxides emitted from vehicle engines.
Meanwhile, exposure to air pollution – especially early in life – is linked to the development of other allergies. A US study found that exposure to the isocyanate chemical found in wildfire smoke and vehicle exhaust It can change skin bacteriaIt causes eczema.
Another studyIn China, 2598 preschool children at this time, the development of food allergies is related to exposure to indoor and outdoor air pollution. “Our study suggests that, in addition to the gut and skin, the airways may be a new pathway for food perception,” the researchers concluded.
Heat waves make air pollution more dangerous
A new area of research is the link between climate change and air pollution. Recent studies have shown that when high temperatures are combined with low air quality, the mortality rate in heat waves increases. According to the European Union research project, high temperatures – defined as the norm in each city – increase the number of deaths by 0.4 percent when pollution levels are low. Mortality was 2.6 percent higher at medium pollution levels, and 8 percent higher at high pollution levels.
Researchers believe there may be two reasons for this. “One is that the heat and the sun themselves change the mix of air pollutants,” he says Clea Katsuyani at Imperial College London. This is associated with high ozone levels and some high levels of secondary particulate matter. Perhaps these wastes are more toxic to human health. The other explanation is perhaps more obvious: “In warmer seasons, people spend more time outdoors and may be exposed to more pollution,” she says.
When it comes to exposure risk, work is just as important as address.
More deprived neighborhoods tend to have poorer air quality, while more affluent, leafy areas have quieter, cleaner streets.
But that trend isn’t always true, he says Ben Barat at Imperial College London. “Some of the most classic postcodes in London have got high levels of pollution,” he pointed out at a conference in London last week. Some affluent areas of west London have poor air quality because they are close to busy city roads, he said.
Your home address is just as important as your work. During a three-year study in LondonSix individuals in the same area of the city, but with different jobs, with personal air quality monitors to monitor their exposure to black carbon – soot particles – throughout the day.
“What we found was a huge difference between those exposed to the lowest levels of pollution and those exposed to the highest,” Barratt told the conference. “What really stood out was the office worker in central London – the most polluted part of the UK – who had a very low exposure because he worked most of the day in a mechanically ventilated office. And the ambulance driver had the highest risk, 2.5 times more [than the office worker]He said.