Key Laboratory for Environmental Pollution Prediction and Control, Gansu Province, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, China.
Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
Environ Int. 2022 Apr;162:107162. doi: 10.1016/j.envint.2022.107162. Epub 2022 Mar 2.
The vegetation burning caused by wildfires can release significant quantities of aerosols and toxic chemicals into the atmosphere and result in health risk. Among these emitted pollutants, Benzo(a)pyrene (BaP), the most toxic congener of 16 parent PAHs (polycyclic aromatic hydrocarbons), has received widespread concerns because of its carcinogenicity to human health. Efforts have been made to investigate the environmental and health consequences of wildfire-induced BaP emissions in Africa. Still, uncertainties remain due to knowledge and data gaps in wildfire incidences and biomass burning emissions. Based on a newly-developed BaP emission inventory, the present study assesses quantitatively the BaP environment cycling in Africa and its effects on other continents from 2001 to 2014. The new inventory reveals the increasing contribution of BaP emission from African wildfires to the global total primarily from anthropogenic sources, accounting for 48% since the 2000 s. We identify significantly higher BaP emissions and concentrations across sub-Saharan Africa, where the annual averaged BaP concentrations were as high as 5-8 ng/m. The modeled BaP concentrations were implemented to estimate the lifetime cancer risk (LCR) from the inhalation exposure to BaP concentrations. The results reveal that the LCR values in many African countries exceeded the acceptable risk level at 1 × 10, some of which suffer from very high exposure risk with the LCR>1 × 10. We show that the African BaP emission from wildfires contributed, to some extent, BaP contamination to Europe as well as other regions, depending on source proximity and atmospheric pathways under favorable atmospheric circulation patterns.
野火引起的植被燃烧会向大气中释放大量的气溶胶和有毒化学物质，并导致健康风险。在这些排放的污染物中，苯并(a)芘（BaP）作为 16 种母体多环芳烃（PAHs）中最具毒性的同系物，因其对人类健康的致癌性而受到广泛关注。人们已经努力研究非洲野火引发的 BaP 排放对环境和健康的影响。然而，由于对野火事件和生物质燃烧排放的认识和数据存在差距，仍存在不确定性。本研究基于新开发的 BaP 排放清单，定量评估了 2001 年至 2014 年非洲的 BaP 环境循环及其对其他大陆的影响。新的清单揭示了非洲野火 BaP 排放对全球总量的贡献不断增加，主要来自人为源，自 21 世纪以来占比达到 48%。我们发现，在撒哈拉以南非洲，BaP 排放和浓度都明显更高，年平均 BaP 浓度高达 5-8ng/m。我们将模拟的 BaP 浓度用于估算因吸入 BaP 浓度而导致的终生癌症风险（LCR）。结果表明，许多非洲国家的 LCR 值超过了可接受的风险水平 1×10，其中一些国家由于 LCR>1×10，面临着极高的暴露风险。我们表明，非洲野火产生的 BaP 排放在一定程度上导致了欧洲以及其他地区的 BaP 污染，这取决于排放源的位置和大气环流模式下的大气传输路径。
