密歇根新闻广播 密歇根新空气质量报告让你一瞥城市概况（在线收听）

Every year, the American Lung Association looks at the state of air pollution in U.S. cities. This year's State of the Air report is out.

The group analyzes data from air quality monitors on two kinds of air pollution: ground-level ozone pollution (aka smog) and particle pollution—tiny particles from power plants and our cars and trucks.

Lyndsay Moseley Alexander directs the American Lung Association's Healthy Air Campaign. She says both kinds of air pollution pose health risks.

"Particularly ozone pollution, when inhaled, can cause coughing, it can trigger asthma attacks and also much more serious symptoms leading to premature death. And particle pollution is similarly ominous. When we inhale tiny particles into our lungs, they can lodge deep there and cause asthma attacks. They can also cause lung cancer, heart attacks, strokes and also premature death," she says.

But she says many parts of Michigan are making progress in reducing both ozone and particle pollution.

"Only Grand Rapids remains ranked among the most polluted for ozone pollution. In fact, (it's) ranked 18th in the nation among most polluted cities for ozone pollution."

The Detroit-Ann Arbor metropolitan area is ranked 44th most polluted for ozone. She says that's an improvement over previous years.

"What we're seeing is the average number of days when air is unhealthy to breathe have gone down."

But it's not all good news.

"The Detroit area is also in the top 25 most-polluted cities for year-round particle levels. Most cities in the nation improved. This area suffered worse levels."

She says the Detroit area did still meet federal standards for year-round particle pollution.

From the report:

The "State of the Air 2016" found continued improvement in air quality in 2012-2014, showing lower levels of year-round particle pollution and ozone. Still, more than half of all Americans—166 million people—live in counties where they are exposed to unhealthful levels of these pollutants.

Thanks to stronger standards for pollutants and for the sources of pollution, the United States has seen continued reduction in ozone and particle pollution as well as other pollutants for decades.

Overall, the best progress came in the continued reduction of ozone and year-round particle pollution, thanks to cleaner power plants and increased use of cleaner vehicles and engines. Continued progress to cleaner air remains crucial to reduce the risk of premature death, asthma attacks and lung cancer. However, a changing climate is making it harder to protect human health.

Moseley Alexander notes there are a number of counties in Michigan (and around the country) that lack air quality monitors—which means there are gaps in the data they have to work with.