@Brendan von Buckingham 6017 wrote:
There’s all sorts of things in urban air. Professionally I work with historic architecture and old buildings. Went to a seminar on historic masonry. When they clean masonry buildings of decades worth of grime, guess what the number one contaminant is. Rubber. Rubber from millions of tires slowly wearing away, every day.
Good point, Brendan.
“Particulate Matter, or PM-2.5, refers to tiny particles that are smaller than 2.5 microns (smaller than the width of a human hair). Particulate matter has several sources including dirt kicked up into the air on paved and unpaved roads, tires and brake linings as they wear down, smoke, vehicle tailpipe emissions, and earth moving activities. Because particulate matter is so very tiny, it easily bypasses your lung’s protective systems.”
http://www.tmacog.org/airqualityfacts.htm
Methodology to Calculate Particulate Matter (PM) 2.5 and PM 2.5 CEQA Significance Thresholds
“Particles in the PM2.5 size range are able to travel deeply into the respiratory tract, reaching the lungs. Exposure to fine particles can cause short-term health effects such as eye, nose, throat and lung irritation, coughing, sneezing, runny nose and shortness of breath. Exposure to fine particles can also affect lung function and worsen medical conditions such as asthma and heart disease. Scientific studies have linked increases in daily PM2.5 exposure with increased respiratory and cardiovascular hospital admissions, emergency department visits and deaths. Studies also suggest that long term exposure to fine particulate matter may be associated with increased rates of chronic bronchitis, reduced lung function and increased mortality from lung cancer and heart disease.”
http://www.health.state.ny.us/environmental/indoors/air/pmq_a.htm
Wearing an effective mask while bike commuting significant distances on high pollution days is looking more and more appropriate.
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