September 11, 2017 Why Medicare patients need to be concerned about air pollution Aside from a few notable exceptions, you likely imagine large foreign megacities like New Delhi and Beijing when the topic turns to air pollution. On the nightly news, we often see shocking scenes of smog-choked streets across the Pacific. However, there may be a similar danger in our own backyards. Air pollution on a global scale Air pollution is typically measured by the volume of small particles in the air - referred to as PM 2.5. If the air in a city had 1 microgram of PM 2.5 per cubic meter, its PM 2.5 level would be one. The World Health Organization (WHO) defines unhealthy air as anything over a PM 2.5 level of 10. In December 2016, the Indian city of New Delhi made headlines when its PM 2.5 level breached the 1000 mark. Data journalist Niall McCarthy reported that, on average, the Chinese city of Xingtai sees PM 2.5 levels above 155. So where does the U.S. fit into all of this? McCarthy found that Bakersfield, California is the most polluted city in the country, with an average PM 2.5 level of 18.2. Indeed, eight of the top 10 most polluted U.S. cities can be found in California. While far below levels seen in China and India, these levels are still unhealthy. While foreign cities attempt to solve their air pollution crises with forest cities and smog vacuums, American physicians should be concerned about rising pollution levels at home. Exposure to high PM 2.5 levels can increase the risk of lung cancer. Diseases caused by air pollution In 2012, the U.S. Environmental Protection Agency (EPA) amended the National Ambient Air Quality Standard for PM 2.5, setting the daily PM 2.5 standard at 12 micrograms per cubic meter. At these levels and higher, air pollution can exacerbate conditions such as asthma, and prolonged exposure may increase the risk of lung cancer, Chronic Obstructive Pulmonary Disease (COPD) and emphysema, according to the group Physicians for Social Responsibility. A recent study from the Harvard T.H. Chan School of Public Health discovered that even a PM 2.5 level of 10 (below the EPA standard) is associated with an increased all-cause mortality rate of 7.3 percent. In other words, even WHO's already strict guideline may not be strict enough to prevent harm. How Medicare patients are affected The Harvard study used a cohort representative of the entire Medicare population. Across the spectrum of individuals, the researchers found "significant evidence of adverse effects related to exposure to PM 2.5 and ozone at concentrations below current national standards." Cleveland Clinic pulmonologist Sumita Khatri warned that some air filters can actually worsen air quality and suggested patients only use high-efficiency particulate arresting (HEPA) air filters at home. To check the air quality near your practice, visit airnow.gov.