One of the best parts of sunny weather is the ability to run, bike, hike or otherwise be active outside. But while there's a host of benefits to exercising outdoors, there's also a downside: air pollution.
Although air quality in the U.S. has improved significantly since the 1990s, it still may cause a staggering number of deaths each year — more than 30,000, according to a July 2019 study published in the medical journal PLOS Medicine.
Researchers looked at over 750 air-quality monitoring stations across the continental U.S. and found that areas with higher levels of particulate matter — small, inhalable particles in the air that mainly come from cars and buses, power plants and industrial sources — had higher death rates from heart and lung diseases like heart attacks, stroke and lung cancer.
Lower levels of pollution were detected in Midwestern and Rocky Mountain states like New Mexico, Colorado and Arizona, while the highest pollution levels — and corresponding death rates — were found in and around Los Angeles and in some Southern states, including Alabama, Arkansas and Oklahoma. Geography seemed to matter less than income, though: Overall, there was more pollution in poorer, less-educated areas.
But if you live in an area with high pollution levels, don't put the kibosh on your morning jog just yet. "The benefits to your blood pressure, heart and brain from being active more than outweigh the health risks from pollution," Edward Avol, an air pollution specialist and professor of clinical medicine at the University of Southern California's Keck School of Medicine, tells LIVESTRONG.com.
Case in point: When another group of researchers looked at more than 57,000 Danish adults who lived in cities with high levels of air pollution, they found that poor air quality didn't offset the health benefits from outdoor activities like biking, walking and gardening, according to a study published July 2018 in the Journal of the American Heart Association.
That being said, it's important to take some precautions. "When you're exercising outside, you're actually increasing your exposure to air pollution because of your body's increased metabolic demands," explains Jack Stewart, MD, a pulmonologist with St. Joseph Hospital in Orange, California. "You're also more likely to be mouth-breathing, which means that you don't have your nose acting as a filter. As a result, you're inhaling more pollutants."
Luckily, there are a few simple ways to lower your exposure to those pollutants when you're working out in the great outdoors.
1. Check Your Air Quality
Before you head out for your daily run or bike ride, check the Air Quality Index (AQI) to determine how clean the air is in your area.
The AQI, which is powered by the Environmental Protection Agency, uses a scale that ranges from 0 (good air quality conditions, no health concerns) to 500 (hazardous air quality that could severely affect your health). In general, an AQI rating of under 100 is fine, although if you're very sensitive to air pollution (if you have asthma, for example), then you'll want to schedule your workouts indoors until the AQI is under 50, says Avol.
Some apps, like Plume Labs' AIR, will tell you in real time what the air quality right outside your door is like, with helpful tips like whether or not it's safe to eat outside.
You can also check the quality of your local air overall by taking a look at the American Lung Association's annual "State of the Air" report, which grades counties and ranks cities based on their pollution levels over a three-year period. Of course, if your city doesn't rank among the cleanest, that may not be grounds to move; but you might consider doing the majority of your workouts inside.
2. Choose Your Route Carefully
Try to stay away from heavily trafficked roads and focus instead on side streets with less traffic. "Even if you live in a big city, simply changing your route so you're running or biking in a neighborhood with less road traffic can really lower pollution levels," says Avol.
Avoid areas with a lot of high buildings, as these can have a "canyon-like" effect, which actually traps pollutants into the street, Avol adds. Parks and wooded trails are ideal, since the trees around you can help filter out air pollution.
3. Remember That Timing Is Everything
Air pollution tends to be worse midday, so it's best to exercise outside either early in the morning or in the early evening, says Stewart. (Just make sure you do it before or after rush hour, since these are times of high pollution.)
Another advantage of these early morning or evening workouts is that these tend to be the cooler times of the day as well. "Heat stresses your body even more, which can make it more susceptible to the effects of air pollution," explains Avol.
4. Be Mindful With Masks
Technically, an N95 mask (found online on sites like Amazon or in stores like Home Depot) can filter out about 95 percent of all pollution particles, says Avol. But there's a catch: It has to fit perfectly.
"It has to be snug to your face, so air won't leak around the sides," explains Avol. "But most people don't want to exercise with a mask that tight, since it may leave them hot and sweaty and they may find it harder to breathe. That's why if you have any concerns about the air quality, you're most likely better off simply taking your workout indoors."
5. Channel Your Inner Advocate
The best way to protect yourself from the effects of air pollution while exercising is to make sure it's not there in the first place. "Your first priority should be to vote for candidates who support the public's interest in clean air," George Thurston, ScD, professor of environmental medicine and population health at the New York University School of Medicine in New York City, tells LIVESTRONG.com.
You can also put pressure on lawmakers to support the Clean Air Act. Sign the act to tell President Trump, the Environmental Protection Agency and your reps in Congress that pollutant-free air matters to you.
- PLOS Medicine: "Particulate matter air pollution and national and county life expectancy loss in the USA: A spatiotemporal analysis."
- Journal of the American Heart Association: "Effects of Leisure‐Time and Transport‐Related Physical Activities on the Risk of Incident and Recurrent Myocardial Infarction and Interaction With Traffic‐Related Air Pollution: A Cohort Study"