I occasionally see a gentleman wearing a N95 Particulate Respirator mask in the Toronto subway, the kind people wore during the SARS outbreak in Toronto.
I would often wonder why? Is he afraid of catching a virus? Here's one more thing for him to worry about when ridding the subway,
Now, the Journal Chemical Research in Toxicology reports that subway dust may trigger lung damage
Subway trains produce airborne dust particles that could damage the lungs of commuters, scientists in France are reporting in a study of the Paris subway system scheduled for the October issue of ACS' Chemical Research in Toxicology, a monthly journal.
Sophie Lanone and colleagues point out that previous studies of the London and Stockholm subway systems also have identified such particulate matter. In their new study, the researchers collected dust samples from platform surfaces in two heavily traveled subway stations in the Paris Metro, which carried one million passengers daily. They exposed live mice and cultured mice cells to the dust over a 24-hour period.
Exposure to the subway dust triggered transient lung inflammation in the mice and increased levels of several substances produced by the immune system that might cause tissue damage. Some but not all effects occur with exposure to diesel exhaust, and other common urban air pollutants, the study said. Subway dust contained large amounts of iron particles and very low levels of endotoxin, a potentially toxic compound produced by bacteria.
"To the best of our knowledge, this is the first evaluation of the biological effects of particulate matter from the Paris subway system as well as the first comprehensive study to evaluate the in vivo effect of subway particulate matter," the report states.
In a related study, scientists are starting to worry about lubricant pollution from cars.
Lubrication oil appears to be an important yet little-recognized source of toxic particle emissions from motor vehicles - even those fueled by clean-burning hydrogen, according to a joint study by government and academic researchers in Washington State and Minnesota. Their study, a step toward more cleaner-burning engines, will be published in the Oct. 1 issue of ACS' Environmental Science & Technology, a semi-monthly journal.
Scientists have long recognized diesel-fueled vehicles as important sources of air pollution that can increase the risk of asthma, bronchitis, and other health problems. Most research, however, has focused on diesel soot, rather than emissions produced by lubrication oil.
In the new study, Arthur L. Miller and colleagues modified a truck diesel engine to run on clean-burning hydrogen instead of diesel fuel, allowing the researchers to focus solely on particle emissions from lubrication oil. They found that the hydrogen-powered engine emitted higher levels of metal-rich particles than the diesel-fueled engine. Lubrication oil was the primary source of these increased emissions. Emission particles identified include calcium, phosphorous, zinc, magnesium, and iron nanoparticles, all of which have the potential to cause lung damage when inhaled over long periods, they say.
"This study's findings may increase current knowledge about the role of lubrication oil in particle-formation dynamics as engine technology improves and cleaner internal combustion engines are developed," the researchers state.