Max Planck Institute for Chemistry , Hahn-Meitner-Weg 1, 55128 Mainz, Germany.
Environ Sci Technol. 2013 Oct 15;47(20):11616-24. doi: 10.1021/es401499q. Epub 2013 Oct 3.
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.
热带和亚热带的森林、草原和农业火灾是广泛污染的来源，并将许多有机物质释放到空气和土壤中，包括持久性有机污染物，即多氯二苯并对二恶英和呋喃（PCDD/Fs）和多环芳烃（PAHs）。本研究使用卫星观测到的植被火灾每日全球排放量和全球多箱化学输送模型，研究了这一来源对非洲人类和环境接触菲、荧蒽、芘、苯并(a)芘、2,3,7,8-四氯二苯并对二恶英、1,2,3,4,6,7,8-七氯二苯并对二恶英和八氯二苯并对二恶英的影响。模型预测的与植被火灾相关的 PAH 和 PCDD 近地面大气浓度分别在 10-1000 和 10(-5)-10(-3) pg m(-3)范围内。研究发现非洲的植被火灾每年排放 180±25 kg 的 PCDD/Fs。与观测结果相比，发现火灾解释了撒哈拉以南非洲农村和背景大气中 PCDD（5%的 2,3,7,8-四氯二苯并对二恶英）浓度的 1-10%。由于缺乏有关排放因子和光化学的知识，植被火灾对 PAH 暴露的贡献可能>10%，但无法量化。敏感性分析表明，PAH 与臭氧的非均相反应有效地限制了大气寿命和长距离传输。
