Air Pollution Assuming an Ever Increasing Role in Asthma

More than 25 million people in the U.S. have asthma and 6 out of 10 of them have the allergic type of asthma.¹ This means that their asthma symptoms are triggered, or brought on, by substances that cause allergic reactions. This can include things like: pollen, mold, dust, animals, and insects.

Unfortunately, the number of people with asthma has been increasing over the past few decades in all age, sex, and racial groups.²

But research is increasingly revealing that another factor may be causing an increase in asthma diagnoses: air pollution.^3,4

The effect of air pollution on asthma

Air pollution can cause asthma symptoms to become worse and trigger asthma attacks in people of any age, but children appear to be especially vulnerable.³ Also, exposure to air pollution during a child's first few years of life has been found to increase the risk of asthma throughout childhood and adolescence. This is especially true after 4 years of age. The Environmental Protection Agency reports on a number of studies linking asthma in kids to air pollution:³

• One study found that African American children were at higher risk from ozone levels than other ethnicities, even when those levels were relatively low.
• Researchers out of Johns Hopkins University found that both fine and coarse particulate matter in outdoor air were responsible for increased asthma diagnoses, as well as hospital and emergency room visits.
• A third study suggested that air pollutants suppress genes that regulate the body's immune system, resulting in the inflammatory response associated with asthma.

Pollution contributes to airway damage

Although scientists are still learning more about how air pollution affects asthma, we do know that pollution leads to airway damage. That, in turn, leads to inflammation and the airways changes typical of asthma. It may also increase the risk of asthma sufferers' sensitivity to allergens.⁴

Air pollution can come from a number of different man-made and natural sources. Air pollution includes:⁵

• Gases
• Smoke from fires and wood-burning stoves
• Volcanic ash
• Dust particles
• Traffic emissions

The burden of traffic-related air pollution on asthma

According to a recent study from researchers at the George Washington University Milken Institute School of Public Health, as many as 4 million children develop asthma each year worldwide as a result of inhaling nitrogen dioxide air pollution.⁶

Study findings

Here are some of the details of this ground-breaking study:

• Based on data from 2010 to 2015
• Approximately 64 percent of the new cases of asthma each year occur in urban areas
• Big cities worldwide have the highest percentage of pediatric asthma linked to air pollution: Los Angeles, New York, Chicago, Las Vegas, and Milwaukee were the top five cities in the U.S.
• China, India, and the U.S. were the 3 countries with the worst incidence of pollution-related childhood asthma

What leaders can do in the future

In an ideal world, we could all live in non-urban areas, where the air tends to be cleaner and less polluted. However, this is obviously not often realistic. Global solutions suggested by the George Washington University researchers include:⁶

• Re-evaluation of the World Health Organization's Air Quality Guidelines for air pollutants
• Improving access to cleaner forms of transportation
• More research to better identify the causative agents within traffic emissions

How you can protect yourself or your child

Meanwhile, the EPA suggests some actions you can take to reduce your exposure to air pollution:⁷

• Choose to live in homes that are more than 200 meters from any major roads.
• Don't travel during rush hour if you can avoid it. And then stay on back roads more than highways, if possible.
• Keep car windows shut while driving, especially in traffic.
• Limit time spent outdoors close to main roads in levels of high pollution, especially in the afternoon and evening.
• Keep track of when air quality is poor, by checking local air quality forecasts.