From Northwestern University NewsCenter:
"It was a murder mystery playing out in major cities across the country and perplexing scientists. Thousands of people were dying from strokes and heart attacks within 24 hours of a spike in microscopic pollution -- tiny particles that spew from the exhaust of diesel trucks, buses and coal-burning factories.
Northwestern researchers have discovered that this microscopic air pollution spurs hyperclotting of the blood. The study found that lungs inflamed by the pollution secrete a substance, interleukin-6, which causes an increased tendency for blood to coagulate or clot.
In the study in mice, researchers observed a 15-fold increase in interleukin-6 24 hours after the mice were exposed to the pollution. In people, interleukin-6 also raises the levels of a substance called CRP, which is correlated with death from cardiovascular disease.
Among the metropolitan areas, Los Angeles has the most year-round particle pollution. Chicago ranks 11; New York, 17 and Washington D.C., 20.
The level of particulate matter in the air in Chicago is 20 micrograms/m3. The level of particulate matter in Beijing is 260 micrograms/m3 — 13 times as much as Chicago.
The risk of dying from a heart attack or ischemic stroke jumps a whopping 30 percent with each additional 10 micrograms of pollution."
Microscopic Pollution May Trigger Heart Attacks/Strokes by Spurring Blood Clots. Northwestern University NewsCenter.
Air Pollution May Hurt the Heart. WebMD.
Image source: Air pollution, Wikipedia, public domain.