Air Pollution Accounts for Millions of Asthma ER Episodes

The wide range of estimates reflects the application of central risk approximations from different epidemiological meta-analyses.

About half of the asthma ER visits attributed to dirty air were estimated to occur in South and East Asian countries, notably India and China. And although the air in the United States is relatively clean compared to South and East Asian countries, ozone and particulate matter were estimated to contribute 8-21% and 3-11% of asthma ER visits in the United States, respectively. The researchers suggest that countries like India and China may be harder hit by asthma burden because they have large populations and tend to have fewer restrictions on factories belching smoke and other sources of pollution.

Human-derived emissions were responsible for about 37% and 73% of ozone and PM2.5 asthma ER impacts, respectively. The remaining impacts were attributable to naturally occurring ozone precursor emissions, such as those from vegetation and lightning, and also due to PM2.5 factors such as dust and sea salt, although several of these sources are also influenced by humans. As reported, the largest ER impacts were found in China and India. The study was published on October 24, 2018, in Environmental Health Perspectives.

“We know that air pollution is the leading environmental health risk factor globally. Millions of people worldwide have to go to emergency rooms for asthma attacks every year because they are breathing dirty air,” said lead author Susan Anenberg, PhD, MSc, associate professor of environmental and occupational health at GW. “The range of global public health impacts from breathing dirty air is even more far reaching, and includes millions of asthma attacks every year. Policies aimed at cleaning up the air can reduce the global burden of asthma and improve respiratory health around the world.”

Asthma is the most prevalent chronic respiratory disease worldwide, affecting about 358 million people. It is characterized by variable, recurring symptoms, reversible airflow obstruction, and bronchospasm. Symptoms include episodes of wheezing, coughing, chest tightness, and shortness of breath, which may occur a few times a day or a few times per week. Diagnosis is usually based on the pattern of symptoms, response to therapy over time and spirometry.

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