Kwarteng Lawrencia, Baiden Emmanuel Acquah, Fobil Julius, Arko-Mensah John, Robins Thomas, Batterman Stuart
Department of Biological, Environmental and Occupational Health Sciences University of Ghana Accra Ghana.
Environmental Health Sciences University of Michigan Ann Arbor Michigan USA.
Geohealth. 2020 Aug 1;4(8):e2020GH000247. doi: 10.1029/2020GH000247. eCollection 2020 Aug.
Air quality information is scarce in low- and middle-income countries. This study describes the application of moderate cost approaches that can provide spatial and temporal information on concentrations of particulate matter (PM) needed to assess community and occupational exposures. We evaluated PM levels at the Agbogbloshie e-waste and scrap yard site in Accra, Ghana, and at upwind and downwind locations, obtaining both optical and gravimetric measurements, local meteorological data and satellite aerosol optical depth. Due to overload issues, the gravimetric 24-hr samplers were modified for periodic sampling and some optical data were screened for quality assurance. Exceptionally high concentrations (e.g., 1-hr average PM exceeding 2000 μg/m) were sometimes encountered near combustion sources, including open fires at the e-waste site and spoil piles. 24-hr PM levels averaged 31, 88 and 57 μg/m at upwind, e-waste and downwind sites, respectively, and PM averaged 145, 214 and 190 μg/m, considerably exceeding air quality standards. Upwind levels likely reflected biomass burning that is prevalent in the surrounding informal settlements; levels at the e-waste and downwind sites also reflected contributions from biomass combustion and traffic. The highest PM levels occurred in evenings, influenced by diurnal changes in emission rates, atmospheric dispersion and wind direction shifts. We demonstrate that moderate cost instrumentation, with some modifications, appropriate data cleaning protocols, and attention to understanding local sources and background levels, can be used to characterize spatial and temporal variation in PM levels in urban and industrial areas.
低收入和中等收入国家的空气质量信息匮乏。本研究描述了采用成本适中的方法,这些方法能够提供评估社区和职业暴露所需的颗粒物(PM)浓度的时空信息。我们评估了加纳阿克拉阿博布罗西电子垃圾和废品场及其上风向和下风向位置的PM水平,同时获得了光学和重量测量数据、当地气象数据以及卫星气溶胶光学厚度。由于过载问题,对重量法24小时采样器进行了改进以进行定期采样,并对一些光学数据进行了质量保证筛选。在燃烧源附近,有时会遇到极高的浓度(例如,1小时平均PM超过2000μg/m),包括电子垃圾场的明火和弃土堆。上风向、电子垃圾场和下风向站点的24小时PM水平分别平均为31、88和57μg/m,PM平均为145、214和190μg/m,大大超过了空气质量标准。上风向的水平可能反映了周围非正式定居点普遍存在的生物质燃烧情况;电子垃圾场和下风向站点的水平也反映了生物质燃烧和交通的影响。最高的PM水平出现在晚上,这受到排放率、大气扩散和风向变化的日变化影响。我们证明,经过一些改进的成本适中的仪器、适当的数据清理协议以及对当地源和背景水平的理解,可用于表征城市和工业区PM水平的时空变化。