May 13, 2008 -- A new study shows that larger particles of air pollution aren't significantly linked to hospital admissions for heart or lung problems.
The goal of the study was to see how larger particulate-matter air pollution might play a role in hospital admissions for cardiovascular and lung disease. Researchers say that fine particles of air pollution have long been studied, but coarser ones have not.
Cardiovascular and lung disease rates were slightly higher in the eastern U.S. than in the West.
Respiratory disease rates were slightly higher in less urban counties.
In the western U.S. there was nearly double the level of coarse particulate matter air pollution (such as from mechanical grinding, agricultural activities, dust) than in the eastern U.S.
The study showed that breathing in coarse particles of air pollution was not significantly associated with emergency hospital admissions when it came to cardiovascular or lung disease.
Researchers say coarse particles can get stuck in the upper and larger airways.
Smaller particles in the air are mainly from vehicle exhaust or combustion. Studies have shown that when breathed deep into the lungs, these smaller particles reach the smaller airways and air sacs of the lungs. The researchers also note that the chemical makeup of particulate pollution can vary by size.
The U.S. Environmental Protection Agency uses these types of studies to set safety standards and regulations on air pollution.
The researchers urge further testing of larger particles.