Mind the Gap

Research studies on wood smoke and other air pollution.

Mind the Gap

Postby Wilberforce » Tue Dec 28, 2010 11:26 pm

Mind the Gap
Kirk R. Smith, Jennifer L. Peel
http://www.ncbi.nlm.nih.gov/pmc/?term=1 ... #abstract0
Background: Recent analysis has demonstrated a remarkably consistent, nonlinear relationship between estimated inhaled dose of combustion particles measured as PM2.5 (particulate matter with aerodynamic diameter ≤ 2.5 µm) and cardiovascular disease mortality over several orders of magnitude of dose—from cigarette smoking, environmental tobacco smoke (ETS) exposure, and ambient air pollution exposure.

Objectives: Here we discuss the implications of this relationship and point out the gaps in our knowledge that it reveals.

Discussion: The nonlinear exposure–response relationship that is revealed—much steeper at lower than at higher doses—explains the seemingly inconsistent risks observed from ambient air pollution and cigarette smoking but also raises important questions about the relative benefits of control at different points along the curve. This analysis also reveals a gap in the evidence base along the dose–response curve between ETS and active smoking, which is the dose range experienced by half the world’s population from indoor biomass and coal burning for cooking and heating.

Conclusions: The shape of the exposure–response relationship implies much larger public health benefits of reductions at the lower end of the dose spectrum (e.g., from reductions in outdoor air pollution) than from reducing the rate of active smoking, which seems counterintuitive and deserving of further study because of its importance for control policies. In addition, given the potential risks and consequent global disease burden, epidemiologic studies are urgently needed to quantify the cardiovascular risks of particulate matter exposures from indoor biomass burning in developing countries, which lie in the dose gap of current evidence.

Editor's Summary

Smith and Peel (p. 1643) note that the seemingly inconsistent relative risks of cardiovascular disease mortality associated with ambient air pollution and cigarette smoking can be explained by a nonlinear dose–response relationship over several orders of magnitude. The shape of the exposure–response curve implies much larger public health benefits of reductions at the lower end of the dose spectrum. However, the authors note that there is a large gap in the literature concerning effects of daily exposure to small-diameter particulate matter (PM2.5) in the dose range associated with indoor biomass and coal burning for cooking and heating. The estimated relative risks and large proportion of the world’s population exposed in this range suggest that these exposures result in a major burden of disease. Therefore, the authors conclude that epidemiologic studies are needed to quantify cardiovascular risks associated with indoor biomass burning and develop appropriate risk reduction and mitigation strategies for PM exposures in the low to intermediate portion of the dose–response curve.
• 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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