Air Pollution Toxicology--A Brief Review of the Role of the Science in Shaping the Current Understanding of Air Pollution Health Risks

Abstract

Human and animal toxicology has had a profound impact on our historical and current understanding of air pollution health effects. Early animal toxicological studies of air pollution had distinctively military or workplace themes. With the discovery that ambient air pollution episodes led to excess illness and death, there became an emergence of toxicological studies that focused on industrial air pollution encountered by the general public. Not only did the pollutants investigated evolve from ambient mixtures to individual pollutants but also the endpoints and outcomes evaluated became more sophisticated, resulting in our present state of the science. Currently, a large toxicological database exists for the effects of particulate matter and ozone, and we provide a focused review of some of the major contributions to the biological understanding for these two "criteria" air pollutants. A limited discussion of the toxicological advancements in the scientific knowledge of two hazardous air pollutants, formaldehyde and phosgene, is also included. Moving forward, the future challenge of air pollution toxicology lies in the health assessment of complex mixtures and their interactions, given the projected impacts of climate change and altered emissions on ambient conditions. In the coming years, the toxicologist will need to be flexible and forward thinking in order to dissect the complexity of the biological system itself, as well as that of air pollution in all its varied forms.

The sensitivities of emissions reductions for the mitigation of UK PM<sub>2.5</sub>

“…The UK Committee on the Medical Effects of Air Pollutants has also recently concluded that reductions in concentrations of both primary and secondary particles are likely to benefit public health (COMEAP, 2015). Nevertheless, although not conclusive, there is evidence that traffic-related sources of PM, or combustion sources more generally, are particularly associated with adverse health outcomes Schlesinger, 2007, 2010;Janssen et al, 2011;Stanek et al, 2011;WHO, 2013;Grahame et al, 2014). The possibility that primary PM 2.5 is more toxic per unit mass than secondary PM 2.5 , places greater emphasis on the finding from this work on the effectiveness of reductions in emissions of primary PM 2.5 .…”

A rapid assessment of the impact of hazard reduction burning around Sydney, May 2016

“…By definition, they address only a sole pollutant in the majority of circumstances, but this can be helpful when it's unclear whether the health effects reported in the real world are related to the actual pollutant or to a mixture of pollutants for which it acts as a tracer. For ozone, clear and extensive literature demonstrates its toxic potency, which has been well reviewed since 2005 (Stanek et al, 2011a; second draft of the EPA's integrated science assessment: EPA, 2012), though there remains the question of whether considering ozone alone underestimates the toxicity associated with the complete photochemical mixture. This point is addressed in the Answer to Question B4.…”

Source and risk apportionment of selected VOCs and PM2.5 species using partially constrained receptor models with multiple time resolution data

“…Air pollutants such as volatile organic compounds (VOCs) and fine particulate matter (PM 2.5 ) are associated with adverse health effects (Kampa and Castanas, 2008;Kim et al, 2013;Pedersen et al, 2014;Seagrave et al, 2006;Stanek et al, 2011). Since air pollutants are emitted from a variety of sources, identifying and quantifying source-specific contributions to the environment and health is needed to design effective control strategies (Heal et al, 2012;Lall et al, 2011).…”