Urban smog causes immediate rise in deaths from heart disease, lung disease

The Environmental Protection Agency says that smog levels above 84 parts per billion threaten public health. This study found that below that level, an increase of only 10 parts per billion leads to more deaths.

Smog, which is formed from chemicals emitted by vehicles and power plants, is the nation�s most widespread air-quality problem.

• An increase in smog sparks a small but measurable increase in deaths, scientists report today in a study showing the strongest link yet between smog and damage to health.
• A study of 95 U.S. urban areas found that a small increase in the average smog level over seven days can lead to a 0.5% rise in deaths, many from heart and lung disease, on the seventh day.
• The researchers' analysis ruled out the possibility that the deaths were caused by heat, different kinds of pollution or other causes.
• Public health officials have long known that breathing smog damages human airways, worsens asthma and leads to a higher risk of lung diseases such as pneumonia.
• The Environmental Protection Agency says that smog levels above 84 parts per billion threaten public health.
• Smog levels in many urban areas exceed 90 parts per billion on sunny summer days.
• The increase in deaths after a smoggy week is "relatively small," says Arden Pope, an air-quality researcher at Brigham Young University in Provo, Utah.
• "The concern is that exposure is ubiquitous and the number of people affected is large.
• You take a small risk and spread it out over huge numbers of people, and you end up with a fairly large impact."
• The study is the largest single investigation of the health effects of smog.
• The results are likely to garner scrutiny from the EPA, which must decide in the next few years whether to hold counties to a more stringent smog goal than they now have.
• The other common form of dirty air that damages health is particle pollution, which exceeds federal standards in about 100 counties.