Air pollution isn’t just something that effects people in the United States. For example, a new study states even a short stay for travelers in cities with high levels of air pollution can lead to breathing problems that can take at least a week to recover from.

Led by researchers at NYU School of Medicine, the study is the first of its kind, according to its authors. It analyzed air pollution-related coughing and breathing difficulties, and recovery times on returning home, in healthy, young adults traveling internationally, said the news release.

Published in early May the Journal of Travel Medicine, the finding is timely given that the number of tourists travelling internationally is expected to grow to 1.8 billion by 2030, according to the World Tourism Organization.

“We had several reports that tourists were feeling sick when visiting polluted cities, so it became important for us to understand what was really happening to their health,” said senior study investigator Terry Gordon, PhD, a professor in the Department of Environmental Medicine at NYU Langone Health in the release.

For the study, researchers analyzed six measurements of lung and heart health in 34 men and women traveling abroad for at least a week from the metropolitan New York City area. Most were visiting family in cities with consistently high levels of air pollution, including Ahmedabad and New Delhi, India; Rawalpindi, Pakistan; and Xian, China.

Some destinations studied ― Beijing, Shanghai, and Milan ― are heavily air polluted during certain months but have relatively cleaner air at other times. Other, mostly European, destinations such as Geneva, London; San Sebastien, Spain; Copenhagen; Prague; Stockholm; Oslo; and Reykjavik had consistently lower levels of air pollution. The research team learned New York City has relatively low levels of air pollution, in part because of strict regulations, its location on the coast, and weather patterns.

Specifically, the study found that being in an air polluted city reduced measures of lung function by an average of 6 percent and by as much as 20 percent in some people. Participants also ranked their respiratory symptoms from one (mild) to five (requiring treatment), reporting a cumulative average symptom score of eight, the study found.

People who visited the highly polluted cities reported as many as five symptoms, while those who visited lower pollution cities had fewer or none. Two patients sought medical attention because of their symptoms. The pollution levels of the cities studied did not make a significant difference in the blood pressure of visitors, researchers said.

All study participants had a normal body mass index (between 21 and 29 for men, and between 18 and 26 for women), and none had pre-existing health conditions. Before embarking on their travels, all were taught how to measure their lung function and heart rate daily using commercially available spirometers (to measure lung function), wrist blood pressure monitors, and heart rate sensors. Researchers then compared the health data against levels of air pollution collected from local government agencies, the release added.

The researchers used international standards to categorize highly polluted cities as those having more than 100 micrograms per cubic meter of particulate matter (PM), or air pollution dust. Moderate pollution is anything between 35 and 100 micrograms per cubic meter of PM, and low pollutions levels are anything less than that, according to the release.

“What travelers should know is that the potential effects of air pollution on their health are real and that they should take any necessary precautions they can,” said study lead investigator M.J. Ruzmyn Vilcassim, PhD, a postdoctoral fellow in the Department of Environmental Medicine about the survey in the release.

Gordon suggested for those visiting highly polluted cities to consider wearing masks or consult a doctor prior to travel if they have pre-existing respiratory or cardiac health difficulties, and to consider avoiding travel during certain months.

Although participants gradually returned to normal health, study investigators found there needs to be more follow-up research to know if there were long-term effects, or if longer stays would influence the pollution impact.

Next, researchers plan to study international travelers who are more susceptible to the effects of air pollution, such as the elderly and people with asthma or heart conditions, the release added.

Funding for the study was provided by National Institute of Environmental Health Sciences grants ES000260 and ES007324, an Air Waste and Management Association 2017 Scholarship, and an NYU College of Global Public Health grant.

Source NYU Langone Health