Short-term exposure to particulate matter

Research studies on wood smoke and other air pollution.

Short-term exposure to particulate matter

Postby Wilberforce » Mon Aug 05, 2013 5:42 pm

Short-term Exposure to Particulate Matter Constituents and Mortality in a National Study of U.S. Urban Communities
Krall et al

Background: While the association between PM2.5 mass and mortality has been extensively studied, few national-level analyses have estimated mortality effects of PM2.5 chemical constituents. Epidemiological studies have reported that estimated effects of PM2.5 on mortality vary spatially and seasonally. We hypothesized that associations between PM2.5 constituents and mortality would not vary spatially or seasonally if variation in chemical composition contributes to variation in estimated PM2.5 mortality effects.

Objectives: We aim to provide the first national, season-specific, and region-specific associations between mortality effects of PM2.5 constituents.

Methods: We estimated short-term associations between non-accidental mortality and PM2.5 constituents across 72 urban U.S. communities from 2000-2005. Using U.S. EPA Chemical Speciation Network data, we analyzed seven constituents that together compose 79-85% of PM2.5 mass: ammonium ion, elemental carbon (EC), nitrate, organic carbon matter (OCM), silicon, sodium ion, and sulfate. We applied Poisson time-series regression models controlling for time and weather to estimate mortality effects.

Results: Interquartile range increases in OCM, EC, silicon, and sodium ion were associated with estimated increases in mortality of 0.39% (95% Posterior Interval (PI): 0.08, 0.70%), 0.22% (95% PI: 0.00, 0.44%), 0.17% (95% PI: 0.03, 0.30%), and 0.16% (95% PI: 0.00, 0.32%), respectively, based on single pollutant models. We did not find evidence that associations between mortality and PM2.5 or PM2.5 constituents differed by season or region.

Conclusions: Our work indicates that some constituents of PM2.5 may be more toxic than others and therefore regulating PM total mass alone may not be sufficient to protect human health.
• The Surgeon General has determined that there is no safe level of exposure to ambient smoke!

• If you smell even a subtle odor of smoke, you are being exposed to poisonous and carcinogenic chemical compounds!

• Even a brief exposure to smoke raises blood pressure, (no matter what your state of health) and can cause blood clotting, stroke, or heart attack in vulnerable people. Even children experience elevated blood pressure when exposed to smoke!

• Since smoke drastically weakens the lungs' immune system, avoiding smoke is one of the best ways to prevent colds, flu, bronchitis, or risk of an even more serious respiratory illness, such as pneumonia or tuberculosis! Does your child have the flu? Chances are they have been exposed to ambient smoke!
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