On the Contribution of Biomass Burning to POPs (PAHs and PCDDs) in Air in Africa

• Published in: Environmental science & technology Vol. 47; no. 20; pp. 11616 - 11624
• Main Authors: Lammel, G, Heil, A, Stemmler, I, Dvorská, A, Klánová, J
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 15.10.2013
• Subjects: Africa; Air - analysis; Air Pollutants - analysis; Air pollution; Applied sciences; Atmosphere - chemistry; Atmospheric pollution; Benzofurans - analysis; Biomass; Combustion and energy production; Dibenzofurans, Polychlorinated; Dioxins; Emissions; Exact sciences and technology; Fires; Forest & brush fires; Models, Theoretical; PCB; Pollution; Pollution sources. Measurement results; Polychlorinated biphenyls; Polychlorinated Dibenzodioxins - analogs & derivatives; Polychlorinated Dibenzodioxins - analysis; Polycyclic aromatic hydrocarbons; Polycyclic Aromatic Hydrocarbons - analysis; Sensitivity analysis; Vegetation; Africa; Dioxin derivatives; Hydrocarbon; Pollutant behavior; Space remote sensing; Satellite observation; Combustion; Biomass; Polycyclic aromatic compound; Mutagen; Organic chlorine compounds; Persistent organic pollutant; Carcinogen; Atmospheric chemistry; Air pollution; Numerical simulation; Poison; Vegetation fire; Organic compounds; Concentration distribution
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es401499q

Forest, savannah, and agricultural fires in the tropics and subtropics are sources for widespread pollution and release many organic substances into the air and soil, including persistent organic pollutants, i.e., polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polycyclic aromatic hydrocarbons (PAHs). The significance of this source for the exposure of humans and the environment in Africa toward phenanthrene, fluoranthene, pyrene, benzo(a)pyrene, 2,3,7,8-tetrachlorodibenzo-p-dioxin, 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin, and octachlorodibenzo-p-dioxin is studied using daily global emissions from vegetation fires observed by satellite and a global multicompartment chemistry-transport model. Near-ground atmospheric concentrations of model-predicted vegetation fire related concentrations of PAHs and PCDDs were in the 10–1000 and 10–5–10–3 pg m–3 ranges, respectively. Vegetation fires in Africa are found to emit 180 ± 25 kg yr–1 of PCDD/Fs. By comparison with observations, it is found that fires explain 1–10% of the PCDD (5% of 2,3,7,8- tetrachlorodibenzo-p-dioxin) concentrations in the rural and background atmosphere of sub-Saharan Africa. The contribution of vegetation fires to exposure to PAH is probably >10%, but cannot be quantified due to lack of knowledge with regard to both emission factors and photochemistry. A sensitivity analysis suggests that the heterogeneous reaction of PAHs with ozone is effectively limiting atmospheric lifetime and long-range transport.