You’re double-checking to make sure you have everything before you leave on a trip: phone . . . wallet . . . respirator mask? Even if you don’t have asthma or another pulmonary condition, it’s something to consider if you’re going to an area with high air pollution.

Poor air quality is more common than you might realize; the World Health Organization says that 91 percent of the population lives in places where air pollution exceeds WHO guidelines. A 2018 report from the Journal of Travel Medicine says ambient air quality may affect “both the acute and chronic state of health of the traveler.”

As the Earth warms, there is more cause for concern. According to the National Climate Assessment, climate change will increase ground-level ozone, which can cause health problems. More drought conditions may bring more wildfires, exposing people to smoke and associated respiratory issues. Research has also “demonstrated the exacerbation of the impact of air pollution on health in hot, dry conditions,” Miriam Byrne, senior lecturer of the Center for Climate and Air Pollution Studies at the National University of Ireland and co-author of the Journal of Travel Medicine study, said by email.

This makes it important to research potential destinations as you craft your travel itinerary. Keep in mind that common wisdom might be outdated. For example, while most people would likely put Beijing near the top of a list of international cities with air pollution, a report from IQAir AirVisual in collaboration with Greenpeace Southeast Asia shows that seven of the 10 most polluted cities are in India, with just one in China (Hotan, in the far west of the country). And you might be surprised that Bakersfield, Calif., tops the American Lung Association’s recently released list of the top 10 cities with the most short-term particle pollution.

Besides research, here are some other steps you can take before you go and while on the road to protect yourself, in case the skies at your destination are not so friendly.

See your doctor

The International Association of Medical Assistance for Travelers ( advises that people with respiratory conditions such as asthma or chronic obstructive pulmonary disease (COPD) see a doctor before traveling and get any medications they may need. Exams are also recommended for the elderly, and those traveling with young children should avoid visiting areas with bad air quality.

Consider a different season

Pollution varies by season, depending on weather and the area you’re visiting. In New Delhi, for example, pollution rises in autumn and winter because of crop burning and India’s festival of lights — Diwali — which involves four nights of fireworks, reports fire researcher Vijay Koul of the Commonwealth Scientific and Industrial Research Organization (CSRIO) of Australia in the academic nonprofit news organization the Conversation.

Indochina’s dry season runs from January through April, which allows factory emissions, crop burning smoke, exhaust and construction dust to accumulate, reports

Summer is traditionally wildfire season in the United States, but the U.S. Forest Service reports that climate change and warmer, shorter winters are making it a year-round issue.

Consult websites and apps

With numerous websites and apps that give real-time air pollution data, it’s easy to be informed.

There are two common ways pollution is measured: PM 2.5 or PM 10. PM 2.5 is the number of particles that are 2.5 microns or less in width per cubic meter of air. These particles are a mix of liquid and solid, can include combustion particles or organic compounds and are too small to be seen by the naked eye, according to the Environmental Protection Agency website. These particles are dangerous because they can “get to the lowest and deepest level of the lungs and even get into the bloodstream,” says Afif El-Hasan, a pediatrician and spokesman for the American Lung Association.

Pollution is also measured in PM 10, particles of 10 micrometers — one-tenth the width of a human hair — or smaller.

The best measure for travelers’ purposes, though, according to Janice Nolen, assistant vice president of national policy for the American Lung Association, is the Air Quality Index, or AQI . This system “considers all monitored pollutants, including ozone and particle pollution in the air,” Nolen says, then rates it in one of five color-coded categories from “good” (code green) to “hazardous,” (code maroon), with instructions for each level.

Nolen says people with asthma or other conditions that make them more sensitive should take precautions even when the level goes up to “moderate” (code yellow), and that at the next level, “unhealthy for sensitive groups” (code orange), everyone should begin taking precautions.

Here are a few sites and apps to explore, recommended by various experts.

• WHO’s Breathe Life campaign shows the air quality rating for 4,300 cities.

AirNow ( is an EPA website that covers air quality in North America.

• IQAir AirVisual has both a website and app. This was my favorite app, with a quick look at an AQI-rated, color-coded list of “your places,” similar to the style on your phone’s weather app. It also provides a 72-hour forecast so you can plan for a bad air day.

World’s Air Pollution: Real-Time Air Quality Index is a site with a world map and easy-view pollution rating.

Bring a mask

While your destination may not have a high pollution rating, conditions can change in a hurry. “During the wildfires that we had in Southern California and Northern California not too long ago, the worst air quality in the world was up in the Bay Area,” says Tiffany Allegretti, public relations manager at IQAir.

It is “reasonable to assume that the same precautions should be taken when traveling to a polluted city or to a wildfire region,” Byrne says, including having any medications such as an inhaler close at hand, “minimizing exercise and time outdoors, and wearing a protective face mask.”

During the California wildfires, El-Hasan recommended an N95 respirator mask — so named because it filters out 95 percent of test particles as small as 0.3 microns. On a heavy pollution day, these are a good bet. “They are easy to get, reasonably effective and relatively cheap,” El-Hasan says. Check with your doctor to see if a mask is okay for you to wear, as some people have a harder time breathing through a mask.

And before you go, make sure the mask fits well. A 2018 study in the journal Occupational and Environmental Medicine tested four disposable face masks on volunteers in Beijing, who were exposed to diesel exhaust while performing active and seated tasks. Most of the masks didn’t provide adequate protection because of movement and poor fit.

Check indoor air quality

When the air quality outside is bad, you want the air inside your hotel to be much better. Hotels are realizing that guests are willing to pay for perks designed to enhance air quality, as well as to facilitate relaxing and sleeping. “More hotels are offering [wellness packages], and more customers are requesting them,” says Rohit Verma, a professor at the Hotel School of SC Johnson College of Business at Cornell University. For example, Stay Well rooms by Delos include air purifiers, aromatherapy and custom lighting to facilitate sleep.

You can also use a portable air monitor such as the IQAir AirVisual Pro to check the quality of the air outdoors and inside. (Taking the monitor on a test run at home, I was astonished to find that the sunroom, long claimed by my cat, wasn’t choked with dander and other pet-related fallout. It was fine. The bedroom with the windows that are stuck shut was the one with the “Unhealthy for Sensitive Groups” rating.)

If you’re in a hotel room with poor air quality, the first thing to do is determine the problem and whether it can be fixed. If there are fumes from a room recently being cleaned, for example, it could be a matter of just opening a window. If the problem is mold or another issue that isn’t immediately resolvable, however, you should ask for a room change.

Curb outdoor activities

On bad air days, keep the exercise inside, El-Hasan says. If you’re planning a jog but the AQI rating is way up, hit the treadmill in the hotel. If you’ve scheduled a bike tour but conditions are bad, consider postponing or taking a tour in an air-conditioned vehicle. Minimize outdoor activity around high traffic or rush-hour times and when there is fire or other pollution-heavy conditions.

“Heed warnings from local authorities regarding being outdoors.” Vickie Sowards, director of nursing resources for Travel Clinics, advised by email.

Know when to seek help

Symptoms of air pollution’s effects can include dry eyes, throat, nose and skin; coughing, sneezing and wheezing; and tiredness and dizziness, which may clear up after you leave the destination. For the very young or the elderly, and people with conditions such as asthma or COPD, pollution can be much more dangerous.

Do not be afraid to seek medical treatment if necessary. “I would take shortness of breath and chest pains very seriously,” El-Hasan says. If you’re outside and feel sick and those symptoms “don’t resolve fairly quickly, you should be seen. You should always err on the side of caution.”

If you feel hot, sweaty, dizzy, short of breath or have chest pain or your breathing starts coming faster, “go to the ER immediately,” Hassan says.

Air pollution is a serious issue: It’s responsible for 4.2 million deaths yearly. But with a bit of research and preparation, plus flexibility when you arrive at your destination, you should be able to breathe a little easier.

Langley is a writer based in Orlando. Find her on Twitter: @LizLangley.

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