| Title: | Health effects from freshly emitted versus oxidatively or photochemically aged air pollutants |
| Author(s): | Weitekamp CA; Stevens T; Stewart MJ; Bhave P; Gilmour MI; |
| Address: | "Center for Public Health and Environmental Assessment, United States Environmental Protection Agency, Research Triangle Park, NC 27711, USA. Center for Public Health and Environmental Assessment, United States Environmental Protection Agency, Research Triangle Park, NC 27711, USA. Electronic address: gilmour.ian@epa.gov" |
| DOI: | 10.1016/j.scitotenv.2019.135772 |
| ISSN/ISBN: | 1879-1026 (Electronic) 0048-9697 (Print) 0048-9697 (Linking) |
| Abstract: | "Epidemiology studies over the past five decades have provided convincing evidence that exposure to air pollution is associated with multiple adverse health outcomes, including increased mortality. Air pollution is a complex mixture of particles, vapors and gases emitted from natural and anthropogenic sources as well as formed through photochemical transformation processes. In metropolitan areas, air pollutants from combustion emissions feature a blend of emitted particles, oxides of carbon, sulfur and nitrogen, volatile organic compounds, and secondary reaction products, such as ozone, nitrogen dioxide, and secondary organic aerosols. Because many of the primary and transformed pollutants track together, their relative contributions to health outcomes are difficult to disentangle. Aside from the criteria pollutants ozone and nitrogen dioxide and some of the simpler aldehydes (e.g. formaldehyde and acrolein), other products from photochemical processes are a particularly vexing class of chemicals to investigate since they comprise a dynamic ill-defined complex mixture in both particulate and gas phases. The purpose of this review was to describe and compare health effects of freshly emitted versus oxidatively or photochemically aged air pollutants. In some cases, (e.g. single volatile organic compounds) photochemical transformation resulted in marked enhancements in toxicity through formation of both known and unidentified reaction products, while in other examples (e.g. aging of automobile emissions) the potentiation of effect was variable. The variation in experimental design, aging system employed, concentration and type of starting agent, and toxicity endpoints make comparisons between different studies exceedingly difficult. A more systematic approach with a greater emphasis on higher throughput screening and computational toxicology is needed to fully answer under what conditions oxidatively- or photochemically-transformed pollutants elicit greater health effects than primary emissions" |
| Keywords: | Air Pollutants/*analysis Air Pollution/*statistics & numerical data Aldehydes/analysis Environmental Exposure/*statistics & numerical data Humans Nitrogen Dioxide/analysis Ozone Particulate Matter/analysis Volatile Organic Compounds/analysis Air pollution; |
| Notes: | "MedlineWeitekamp, Chelsea A Stevens, Tina Stewart, Michael J Bhave, Prakash Gilmour, M Ian eng EPA999999/ImEPA/Intramural EPA/ Review Netherlands 2019/12/16 Sci Total Environ. 2020 Feb 20; 704:135772. doi: 10.1016/j.scitotenv.2019.135772. Epub 2019 Nov 30" |
