PDF(Pubmed)
Abstract：
Air pollution is the leading environmental cause of death globally, and most mortality occurs in resource-limited settings such as sub-Saharan Africa. The African continent experiences some of the worst ambient air pollution in the world, yet there are relatively little African data characterizing ambient pollutant levels and source admixtures. In Uganda, ambient PM2.5 levels exceed international health standards. However, most studies focus only on urban environments and do not characterize pollutant sources. We measured daily ambient PM2.5 concentrations and sources in Mbarara, Uganda from May 2018 through February 2019 using Harvard impactors fitted with size-selective inlets. We compared our estimates to publicly available levels in Kampala, and to World Health Organization (WHO) air quality guidelines. We characterized the leading PM2.5 sources in Mbarara using x-ray fluorescence and positive matrix factorization. Daily PM2.5 concentrations were 26.7 μg m-3 and 59.4 μg m-3 in Mbarara and Kampala, respectively (p<0.001). PM2.5 concentrations exceeded WHO guidelines on 58% of days in Mbarara and 99% of days in Kampala. In Mbarara, PM2.5 was higher in the dry as compared to the rainy season (30.8 vs 21.3, p<0.001), while seasonal variation was not observed in Kampala. PM2.5 concentrations did not vary on weekdays versus weekends in either city. In Mbarara, the six main ambient PM2.5 sources identified included (in order of abundance): traffic-related, biomass and secondary aerosols, industry and metallurgy, heavy oil and fuel combustion, fine soil, and salt aerosol. Our findings confirm that air quality in southwestern Uganda is unsafe and that mitigation efforts are urgently needed. Ongoing work focused on improving air quality in the region may have the greatest impact if focused on traffic and biomass-related sources.
摘要：
空气污染是全球主要的环境死亡原因，大多数死亡发生在资源有限的地区，如撒哈拉以南非洲。非洲大陆经历了世界上最严重的环境空气污染，然而，描述环境污染物水平和源混合物的非洲数据相对较少。在乌干达,环境PM2.5水平超过国际卫生标准。然而,大多数研究只关注城市环境，没有描述污染物来源。我们测量了Mbarara的日常环境PM2.5浓度和来源，乌干达从2018年5月到2019年2月使用配备有尺寸选择入口的哈佛冲击器。我们将我们的估计与坎帕拉的公开水平进行了比较，以及世界卫生组织（WHO）空气质量指南。我们使用X射线荧光和正矩阵分解来表征Mbarara中主要的PM2.5来源。姆巴拉拉和坎帕拉的PM2.5日浓度分别为26.7μgm-3和59.4μgm-3，分别(p<0.001)。在Mbarara，PM2.5浓度超过了世卫组织指南，其中58％的天数超过了Kampala的99％。在姆巴拉拉,与雨季相比，旱季的PM2.5较高（30.8vs21.3，p<0.001），而在坎帕拉没有观察到季节性变化。在这两个城市，PM2.5的浓度在工作日和周末都没有变化。在姆巴拉拉,确定的六个主要环境PM2.5来源包括(按丰度排序)：与交通有关的，生物质和二次气溶胶，工业和冶金，重油和燃料燃烧，细土,和盐气溶胶。我们的发现证实，乌干达西南部的空气质量是不安全的，迫切需要缓解措施。如果将重点放在交通和与生物质有关的来源上，则正在进行的以改善该地区空气质量为重点的工作可能会产生最大的影响。
