Last month, the American Lung Association released its annual State of the Air — 2018  report. In it, the ALA gives grades to the nation’s counties and metropolitan areas based on three parameters: Ground-level ozone (ie. “smog”), fine particle pollution (PM2.5) over 24-hour periods (ie. short term or daily spikes), and year-round fine particle pollution. As you can see in the graphic above, Allegheny County earned failing grades for all three. Nine other counties in the United States also failed all three measures, all of them in California.

That means Allegheny County residents are breathing the dirtiest and most dangerous air east of California. Think about that for a moment.

The Pittsburgh metropolitan area, which includes the area between Pittsburgh, New Castle, and Weirton, WV, fell to eighth-worst among 187 metropolitan regions for year-round particle pollution and tenth-worst out of 201 metro areas for short-term particle pollution. As a whole, the region ranked 32 out of 227 metro areas for ozone pollution (which, actually, represents a slight improvement from last year’s State of the Air report).

It is no secret why this region has big problems with its air quality. While Pittsburgh lies downwind from major industrial point sources of pollution, including coal-fired power plants in the Midwest, most of the air pollution is generated locally and regionally. Significant coke production and steelmaking still goes on in the Monongahela River Valley. The Cheswick Generating Station continues to burn coal, producing prodigious quantities of toxic air emissions and water discharges into the Allegheny River and earning its #1 ranking in PennEnvironment’s most recent Toxic Ten list honestly. (A few miles west and upwind of Downtown Pittsburgh, just across the Allegheny/Beaver county line, is the even bigger Bruce Mansfield coal-fired power plant.) Heavy diesel truck traffic on the area’s highways and roads significantly contributes to the regional pollution load.

Doctors know from decades of occupational medicine and community-based public health research that breathing polluted air causes adverse cradle-to-grave health effects. Ground-level ozone, which forms when volatile organic compounds (VOCs — the “fumes” of fossil fuels) combine with nitrogen oxides (NOx — produced when coal, oil, and natural gas are burned) in the presence of sunlight and heat, negatively impacts every human’s lung function. It doesn’t matter whether you are young or old, rich or poor, physically fit or sedentary — on days that ozone levels are high, everyone’s pulmonary function is diminished. Benzene, a VOC, is linked to serious birth defects in newborns and is a known carcinogen (leukemia in children); another VOC, toluene, can cause permanent neurologic damage. There is abundant data linking fine particulate matter (PM2.5) pollution to complications of pregnancy (impaired fertility, miscarriage, prematurity, low birth weight), childhood developmental problems (behavioral problems, ADHD, learning disabilities, autism), and the development and exacerbation of asthma in children. There are some areas in Allegheny County where my colleague, Dr. Deborah Gentile (Pediatric Alliance — Allergy, Asthma and Immunology Division), found schoolchildren having nearly three times the rate of asthma compared to the rest of the nation. For these kids, more days breathing high levels of fine particle pollution means more missed school days due to illness, more visits to the doctor or emergency department, more expensive medications taken, and more time struggling to breathe. There is something seriously wrong and unjust with this situation that it is allowed — that we allow it — to happen.

Adult health is also adversely affected by air pollution. On days when air quality is poor, those with chronic lung disease such as asthma and COPD find it more difficult to breathe, leading to a greater burden on the healthcare system, on the economy, and on their families. Heart attacks and strokes are more likely to happen on days when the air quality index is not “good.” We’ve known for decades that prolonged exposure to fine particle pollution causes lung cancer and is associated with the development of other tumors in adults; Allegheny County ranks in the top 2% of U.S. counties for cancer risk even as tobacco smoking has declined dramatically. Finally, no one should underestimate the impact environmental degradation and destruction has on the mental health of those who witness it. This is especially true in children.

Globally, the World Health Organization recently estimated that 7 million people die prematurely each year as a result of breathing polluted air inside and outside their homes, and that includes tens of thousands of Americans. WHO says that 90% of the world’s population breathes unhealthy air today. Despite that fact that in the United States — and especially in the Pittsburgh region — the air has been looking cleaner versus back in the day (thanks in large part to the Clean Air Act and other environmental laws written to clear the air and protect the public’s health), the ALA’s findings suggest that looks can be deceiving:

More than four in 10 people (41 percent) in the United States live in counties that have unhealthful levels of either ozone or particle pollution. More than 133.9 million people live in the 215 counties that had unhealthy ozone or particle pollution in 2014-2016.


Two groups that are most vulnerable to the adverse health effects of air pollution, adults 65 and over and children, are considered in the ALA’s data:

Nearly 18.3 million adults age 65 and over and more than 31.3 million children under 18 years old live in counties that received an F for at least one pollutant. More than 1 million seniors and more than 2 million children live in counties failing all three tests.


Despite everything we have learned for decades about the adverse health impacts caused by air pollution, there are several reasons why making the air safe to breathe remains an essential environmental, economic, and public health challenge. We’ll have more on that tomorrow on The PediaBlog.