Comparison of Ambient PM Risk with Risks Estimated from PM Components of Smoking and Occupational Exposures

Abstract

Air pollution studies are based on individual-level health response data and group-level exposure data. Therefore, exposure misclassification occurs, and the results may be biased to an unknown magnitude and direction. Testing the validity of such associations requires a study design using individual-level data for both exposure and response. One can test the plausibility of group-level PM risk estimates by comparing them to individual-level estimates of risk from constituents of ambient air. The twofold purpose of this review is to consider the internal consistency of risks estimated from the three major PM cohort studies and to determine individual-level mortality risks associated with ambient concentrations of tobacco smoke and occupational exposures and compare them with risks associated with ambient PM.The paper demonstrates the risks are not consistent within and between the PM cohort studies. Higher ambient concentration risks (ACRs) from the ambient PM cohort studies are not coherent with ACRs derived from individual-level smoking and occupational risks for total, cardiopulmonary, and lung cancer mortality. Individuallevel studies suggest increased risk of mortality cannot be measured with reliability at concentrations found in ambient air.

Health Effects of Fine Particulate Air Pollution: Lines that Connect

“…Although there are well-established indoor health risks from ETS and biological particles, no substantial or consistent health signal from PM is apparent. 75 Gamble and Nicolich 76 conclude that the risks from the cohort studies were not coherent with the risks derived from smoking or occupational studies. The review does not address this question.…”

Comparative Health Impact Assessment of Local and Regional Particulate Air Pollutants in Scandinavia

“…Gamble and Nicolich have argued that the PM doses required to elicit adverse effects in humans by active smoking and various occupational exposures are orders of magnitude higher than doses obtained from ambient PM exposures (131). However, when ambient PM exposures are compared to environmental tobacco smoke (ETS) exposure, the doses are of comparable magnitude, and IARC has recently decided that ETS should be classified as a proven human carcinogen (132 …”

Effects of sidestream cigarette smoke exposure on baroreflex components in spontaneously hypertensive rats

“…Moreover, the inspired dose of fine particles from ambient pollution is extremely small compared to that from sidestream cigarette smoke (SSCS) (Gamble and Nicolich 2000;Stinn et al 2005;Tricker et al 2009). A study of ambient fine particulate pollution and secondhand cigarette smoke estimates that its cardiovascular mortality effect is much higher than would be expected on the basis of effects extrapolations of active cigarette smoking that assumes a linear dose-response relationship that goes through the origin (Howard and Thun 1999).…”