stateoftheairThe American Lung Association’s State of the Air — 2016 report shows improvement in air quality in many parts of the country. Still, Erik Ortiz writes that the news isn’t all rosy:

Some 166 million Americans — or more than half of the total population — are in unhealthy hot spots with air pollution that puts them at risk for premature death and health issues such as lung cancer, asthma and cardiovascular damage, the study says.


That means that more than half of American men, women, and children live where the air quality is harmful to health. California leads the list of states with the poorest air quality. Even though Los Angeles achieved its highest grade since the ALA started reporting on air quality around the nation in 2000, it still has the worst ozone pollution anywhere in the U.S.

Two types of pollutants dirty the air and threaten the health of people, especially children, those who are sick, the elderly, and those living in poverty. Ozone in the upper atmosphere protects us from the sun’s harmful ultraviolet rays — it’s a good thing high up in the sky. Ground-level ozone, on the other hand, is very bad for us to breathe. This ozone is formed when volatile organic compounds and nitrogen dioxide combine in the presence of sunlight. (VOCs and nitrogen dioxide are both produced by burning  fossil fuels — oil, coal, and natural gas — for generating power and electricity.) We’ve explored air pollution due to ozone several times previously on The PediaBlog.

Particulate matter is the second kind of air pollution that adversely affects human health. Particulate matter comes in all sizes, but fine particles (2.5 microns or less) and ultrafine particles (0.1 microns) appear to be most harmful since they can make their way into the deepest parts of the lungs and be absorbed into the bloodstream. (For the purposes of comparison, the tiniest sand grain is about 90 microns; the diameter of a human hair is 70 microns. These particles were are talking about are really small!) When you sit behind a truck spewing black soot, or you are seeing smoke coming from a fire, that is particulate matter (and some other dangerous things as well). The larger the particles, the more visible they are. One reason the air is looking cleaner nowadays is partly because industry and individuals have learned to be cleaner and emit few particles, and partly because modern high-tech industries emit tinier particles than industries of the past.

Believe it or not, air pollution has been widely studied for years here and abroad. There are numerous studies that consistently show cradle-to-grave adverse health effects from chronic exposure to particulate matter and ozone. For example, we have known for some time that chronic exposure to air pollution causes:

>> complications of pregnancy, including difficulty getting pregnant, increased risk of miscarriage, premature births, low birth weight, infant mortality, and birth defects associated with disrupted embryonic organogenesis;

>> infant developmental problems. Exposure to air pollution during pregnancy has been associated with the development of autism, ADHD, and childhood obesity;

>> exacerbations of childhood asthma. Poor air quality days can be the lone or contributing trigger to an asthma attack where a child coughs, wheezes, and has difficulty breathing, and can make other existing pediatric lung conditions worse;

>> exacerbations of adult lung disease, including COPD, emphysema, asthma, silicosis, pulmonary fibrosis, etc.;

>> adult heart disease. Air pollution has been shown to contribute to the genesis of coronary artery disease and the occurrence of heart attacks;

>> cerebrovascular disease (strokes);

>> cancer, especially lung cancer;

>> premature death.


Of course, there are other air pollutants in addition to ozone and particulate matter — polycyclic aromatic hydrocarbons related to energy production and plastics manufacturing, radon gas and other naturally-occurring radioactive materials, carbon monoxide, and carbon dioxide (the predominantly important greenhouse gas responsible for global warming) — that are unique to specific industries and have their own spectrum of adverse health effects:

Toxic, or hazardous, air pollutants cause or are suspected of causing cancer, birth defects, or other serious harms. They can be gases, like hydrogen chloride, benzene or toluene, dioxin, or compounds like asbestos, or elements such as cadmium, mercury, and chromium. The U.S. Environmental Protection Agency has classified 187 pollutants as hazardous.


The American Lung Association’s report is really well-written and accessible to anyone who wants to learn more about the air we breath 16-20 times a minute (at rest and in good health). I know that life gets busy and we all accept a little risk in order to live in this amazing modern world of ours. But what is risky to our health builds up and threatens all of us.

The smoke from a truck’s exhaust doesn’t disappear; it is simply diluted by less dirty air until you don’t see it anymore. Earth is a closed system; what happens here stays here. Air pollution doesn’t disappear. It builds up and builds up until, eventually, it starts to make people, other life forms, and even the climate system sick.

Tomorrow we’ll look at a new study which puts a price tag on one adverse outcome of pregnancy which results from air pollution: Preterm births.