In April, the American Lung Association released the 2015 State of the Air report. The report revealed that, while air quality in the United States is improving, roughly half of the population live in areas where air pollution levels exceed the annual Environmental Protection Agency limits, making even breathing dangerous.
Now, a study of air pollution in New England shows that the number of people at risk may be much higher. Researchers report today in Environmental Health Perspectives that air pollution increased death rates in people 65 and older, even in zip codes where pollution levels were well below the pollution limits imposed by the EPA.
The health consequences of inhaling fine particulate matter—tiny airborne particles of chemicals, metals, soil, and dust—are well known. Inflammation, heart disease, respiratory illnesses, and early death have all been linked to air pollution exposure. The EPA counters these effects by imposing restrictions on acceptable particulate levels nationwide. Currently, the amount of fine particles present in the air cannot exceed 35 micrograms per cubic meter on any given day, or an average of 12 μg/m3 in a year. (For perspective, some quick math from study author Liuhui Shi shows that, gathered together, 12 μg/m3 of fine particles would weigh about as much as a sesame seed on your morning bagel.)
"Particle levels well below the current EPA standards are killing people."
Previous studies have focused on the link between pollution and health in America's notoriously smoggy major cities, according to Shi. That comes at the expense of suburban and rural pollution levels, which are harder to monitor and have been mostly ignored. To create comprehensive estimates of pollution in both cities and rural areas, the researchers combined pollution estimates from land-based monitoring stations and satellite Aerosol Optical Depth measurements, which predict pollutions levels by measuring how much sunlight airborne particles prevent from reaching the ground.
"Satellite remote sensing allows us to estimate particle concentrations everywhere, in urban areas as well as in rural areas," says Shi, a doctorate student in Environmental Health at Harvard T.H. Chan School of Public Health, and lead author on the new study. This makes their results some of the first on pollution and health risks that are generalizable to populations outside of the big cities.
Shi and her colleagues compared pollution levels to health data from Medicare-covered New England residents aged 65 and up, and used statistical tests to assess both the short- and long-term mortality risks associated with air pollution exposure. The study found that for every 10 μg/m3 increase in particles over a short, two-day period, the risk of death increased by 2.14 percent for the study participants. Over a year-long period, every 10 μg/m3 increase in particulates increased mortality rates by 7.52 percent.
The takeaway, according to Shi, is that the EPA needs to tighten its restrictions on air pollution even further. "Particle levels well below the current EPA standards are killing people," Shi says.
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