May 1, 2008 -- Up to 125 million Americans are breathing air that puts their
health at risk, a report released Thursday by the American Lung Association
The report shows that dozens of U.S. cities and counties regularly have
unsafe levels of particulate and ozone smog pollution. Such pollution is a risk
factor for worsening illness in people with asthma
and other diseases but could also pose risks to healthy people, the report
The annual report ranks U.S. cities and counties on the number of unsafe air
days throughout the year.
"Los Angeles remains the most ozone-polluted city in the nation,"
American Lung Association Vice President Janice Nolan told reporters. The city
also scored at the top of the list for worst year-round particulate
pollution is produced when exhaust from cars, power plants, and other
sources reacts chemically in sunlight. Particle
pollution is a mix of solid particle and liquid droplets in the air. It can
include soot, dust, pollen, chemicals, and metals.
Both forms of pollution can worsen conditions such as bronchitis, asthma, emphysema, and cardiovascular disease.
"This process wreaks havoc in people with chronic lung disease,"
says Norman H. Edelman, MD, the American Lung Association's chief medical
Overall ozone levels dropped about 7% nationwide between 1997 and 2006,
according to Environmental Protection Agency (EPA) data. But the EPA
angered environmental groups in March when it set a more lax ozone pollution
standard than scientific advisors said was necessary to protect human
A report issued last week by the National Academy of Sciences
(NAS) confirmed that ozone pollution poses risks to children, the elderly,
and people with chronic diseases. But NAS experts also issued a statement
declaring that "premature deaths are not limited to people who are already
within a few days of dying."
After Los Angeles, cities with the worst year-round particle pollution
After Los Angeles, cities with the worst ozone pollution included: