Providing perspective for interpreting cardiovascular mortality risks associated with ozone exposures

Abstract

When identifying standards for air pollutants based on uncertain evidence, both science and policy judgments play critical roles. Consequently, critical contextual factors are important for understanding the strengths, limitations, and appropriate interpretation of available science, and potential benefits of risk mitigation alternatives. These factors include the relative magnitude and certainty of the risks posed by various factors and the impacts of other risk factors on air pollutant epidemiology study findings. This commentary explores ozone's status as a risk factor for cardiovascular mortality in contrast with decades of strong and consistent evidence for other established risk factors. By comparison, the ozone evidence is less conclusive, more heterogeneous, and subject to substantial uncertainty; ozone's potential effects, if any, are small and challenging to discern. Moreover, the absence of a demonstrated causal relationship calls into question efforts to quantify cardiovascular mortality risks attributed to ozone exposures on a population level and highlights the need to explicitly acknowledge this uncertainty if such calculations are performed. These concerns are relevant for other similar policy contexts - where multiple established risk factors contribute to the health impact of interest; exposure-effect associations are relatively small, weak, and uncertain; and a causal relationship has not been clearly established.

Ambient air pollution and emergency department visits among children and adults in Casablanca, Morocco

“…The most health-damaging particles are those with a diameter of 10 microns or less (PM 10 ), which can penetrate and lodge deep inside the lungs [10] . Ozone is one of the major constituents of photochemical smog and it has been associated with increases in mortality and hospital admissions due to respiratory and cardiovascular disease [13] – [15] . Largest epidemiologic studies of air pollution suggests that short-term exposure to NO 2 [16] and SO 2 [17] is associated with adverse health effects and increased mortality risk.…”