America's air is markedly cleaner than it was nearly 40 years ago, when the Clean Air Act was passed. Toxic chemicals, smog and soot are less pervasive today. But science has also taught us, since then, that lower levels of pollutants do serious harm -- to our lungs, our hearts and circulatory systems and to the development of our children. Science has shown that, despite significant reduction in acid rain, mountain streams are still struggling to recover from decades of abuse, leaving water there toxic to much fish and plant life.
In other words, as the American Lung Association's 10th annual State of the Air puts it: "Air pollution continues to threaten the lives and health of millions of people in the United States despite great progress since the modern Clean Air Act was first passed in 1970. Even as the nation explores the complex challenges of global warming and energy, air pollution remains widespread and dangerous."
The report, released this week, focuses on the two forms of air pollution most dangerous to lungs: Smog (a.k.a. ozone) and soot (a.k.a. fine particulates). Particulate pollution was analyzed in two ways -- short-term and long-term levels.
Ozone forms on hot sunny days when smokestack and tailpipe pollution interacts with heat and sunlight. The result is ozone, a major component of smog. It's the same molecule that, in the upper atmosphere, protects our skin from harmful radiation from the sun; but at ground level it scars lung tissue, causing permanent damage and making it unhealthy to exercise or, for sensitive individuals like the young, the elderly and those with lung disease, even breathe. Particulates can come in the form of familiar dust and soot, but also in the form of chemicals that form as tiny droplets after being spewed out of tailpipes and smokestacks.
More than 175 million Americans -- six in 10 -- live in counties where high ozone levels were detected -- nearly twice as many as were at risk in 2008. That increase is largely due to new government calculations that account for new scientific understanding of risk of exposure at lower levels for shorter durations.
Even as cities have taken steps to reduce pollution sources, global warming is producing more hot sunny days, extending the ozone pollution season (April heat wave, anyone?) and increasing the number of days likely to produce unhealthy levels of ozone pollution.
Of the 25 most-polluted U.S. cities, 16 had worse ozone pollution than one year ago, according to the American Lung Association. Thirteen had worse particulate pollution.
City data unavailable at the moment.
But most people are not in those clean counties. One in eight lives in a county where all three pollutants reach unhealthy levels, according to the American Lung Association. Among them, at least 4 million children and 10.9 million adults with asthma are exposed to unhealthy air. At least 20.4 million adults over age 65, and 44 million children under the age of 18 are exposed to unhealthy air. And at least 4.4. million people with chronic bronchitis, and 2.1 million people with emphysema are exposed to unhealthy air.
Air pollution isn't just a risk factor for lung disease, but heart disease and diabetes, too, research shows. At least 24.5 million people with cardiovascular diseases and 5.2 million people with diabetes are exposed to unhealthy air.
What can be done? The American Lung Association recommends these actions:
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