Hot summer days can bring spikes in air pollution, as traffic exhaust and other emissions bake in the sun.
Scientists have linked dirty air to a long list of health problems, and the danger can seem all the more frightening because, unlike with many other risks, we have no choice about breathing. But while most of us do not have the power to make the air cleaner, there are some things individuals can do to protect themselves.
Steps like changing travel and exercise routes, buying an air purifier and choosing not to light a fire at home can reduce your exposure to air pollution in any season, experts say.
“It’s basically about awareness,” said Frank Kelly, director of the Environmental Research Group at King’s College London. “You need to understand where you’re being exposed the most, and then you need to be able to take measures to avoid that.”
Doing so is especially important for those most vulnerable to dirty air’s effects — children, older people and those with heart or lung conditions.
The evidence on pollution’s dangers is powerful. It is linked not just to breathing problems but also to increased rates of heart attacks, strokes, cancer, dementia, premature birth and much more. Those who live with polluted air are more likely to die prematurely.
While the United States’ air quality has improved significantly since the 1970 Clean Air Act became law, dirty air still cuts short more than 100,000 American lives every year.
Here are some things you can do to help protect yourself and your family.
Choose Your Route Wisely
As researchers have focused recently on hyper-local variations in pollution levels, they have come to understand that within the same city — even the same neighborhood — individuals take in different amounts of contamination, depending on exactly where they live, and where their routines take them.
That insight offers a measure of control. When walking, running or biking, “the things you can vary are, where do you go and when do you go,” said Darby Jack, associate professor of environmental health at Columbia University’s Mailman School of Public Health. “With both of those, some relatively small changes in behavior can result in meaningful changes in exposure.” Limiting exposure is particularly important during exercise, when we take in more air.
Steering clear of the busiest roads, even just by choosing a parallel route a block away, can halve the pollution you breathe, Dr. Kelly said. The Environmental Defense Fund, an advocacy group, analyzed data from Oakland, Calif., and found pollution levels can vary by as much as eight times in the space of one block.
Route choice is as important for drivers as for pedestrians, since exhaust fumes can become concentrated inside a car. “It’s just like a mini-gas chamber,” Dr. Kelly said.
While it is easy to feel protected inside a sealed car, walking on a traffic-clogged road generally exposes you to less pollution than driving on one, he said.
Testing the air along New York’s bike paths, Dr. Jack — in research conducted with Steven Chillrud, of Columbia’s Lamont-Doherty Earth Observatory — found levels of sooty black carbon were 25 percent lower on those more than 50 meters away from roads designated as truck routes than those on or near truck routes, he said.
Time of Day Matters
Traveling at less polluted times also helps. Rush hours, of course, generally bring pollution peaks. Less obvious is that in many places air quality is worse in the morning, because of a meteorological condition known as temperature inversion, in which a warm layer of air holds down a colder one, trapping pollution in place.
Inversions do not happen everywhere, so researching local conditions is important.
Dr. Jack suggested using one of the new generation of portable or wearable monitors to learn when and where air is most breathable. “You can do some little experiments,” he said, and see what readings are “if I ride at 7 in the morning, if I ride at 9 in the morning, if I ride on this route.” In New York, he said, “you do see pretty significant differences riding the bike path that goes along the river versus riding the bike path that goes in the street canyon” of Midtown.
Avoid Wood Fires
While they may seem more natural than cars and trucks, wood fires are also a pollution source, producing smoke that is thick with the tiny pollution particles that penetrate deep into the body and are dangerous to health. Choosing not to light one is a simple way to reduce the pollution you — and your neighbors — breathe.
A Reality Check on Masks
Pollution masks may seem like an easy fix, but the reality is murkier. While many successfully filter out pollution in the lab, they are less effective in practice, because if they do not seal tightly to the face, dirty air can seep around them, said Miranda Loh, head of environmental and public health at the Institute of Occupational Medicine, a research firm based in Edinburgh.
Even masks that fit well at first often shift when the wearer moves around or talks, said Dr. Loh, who has tested masks available commercially.
“I wouldn’t say don’t bother” wearing one, she said. But know that even a high-quality mask may not live up to its label’s promises. “If you wear it and it fits you, even if it moves a little bit, you’re still getting some protection. But what we don’t want people to think is they shouldn’t take other protective measures, they shouldn’t be cautious.”
Consider an Air Purifier
Home air purifiers may provide some benefits. They can be particularly useful in the western United States, where smoke from increasingly frequent and intense wildfires has blanketed cities such as Los Angeles, San Francisco and Seattle, pushing pollution dangerously high, said Dr. Kari Nadeau, director of the Sean N. Parker Center for Allergy & Asthma Research at Stanford University, who has studied the devices’ effectiveness.
It is important to choose the right purifier — HEPA (High Efficiency Particulate Arrestance) models are best — and use it in a room of the size it is intended for, Dr. Nadeau said.
“They can’t get out everything,” and are unable to remove some of the toxins that wildfire smoke carries, she warned. “Nevertheless, it’s better to have one than not. “
No protective measure, though, can substitute for policies and regulations that make the air cleaner. The best advice for combating pollution, Dr. Jack said, can be summed up in one word: “Vote.”
Beth Gardiner is the author of “Choked: Life and Breath in the Age of Air Pollution.”
