In Cook County, for example, about once every five days you'll have an increase in fine particulate matter of 10 units or more, so this happens quite often.

This means that a reduction in fine particulate matter levels should provide health benefits in terms of lower hospital admissions for the elderly.

Our study is specific to the elderly, but there is epidemiological evidence that air pollution also affects the health of the younger population.

When we analyzed the data for heart failure, we observed a 1.28 percent increase in admissions for each 10 microgram per cubic meter increase in fine particle pollution. Most of these admissions increases occurred the same day as the rise in fine particle concentration, which suggests a short lag time between the change in pollution and the subjects' response.

This study provides strong evidence that daily hospital admission rates for cardiovascular diseases and respiratory diseases are higher when the fine particulate matter levels are increased from one day to the next.

When we analyzed the data for heart failure, we observed a 1.28% increase in admissions for each 10 mg per cubic meter increase in fine-particle pollution. Most of these admissions increases occurred the same day as the rise in fine-particle concentration, which suggests a short lag time between the change in pollution and the subjects? response.