Department of Environmental Health Sciences, Jonathan and Karin Fielding School of Public Health, University of California, Los Angeles, Los Angeles, CA, 90095, USA.
Department of Epidemiology, Jonathan and Karin Fielding School of Public Health, University of California, Los Angeles, Los Angeles, CA, 90095, USA.
Environ Pollut. 2022 Jan 1;292(Pt A):118356. doi: 10.1016/j.envpol.2021.118356. Epub 2021 Oct 12.
The inorganic components of particulate matter (PM), especially transition metals, have been shown to contribute to PM toxicity. In this study, the spatial distribution of PM elements and their potential sources in the Greater Los Angeles area were studied. The mass concentration and detailed elemental composition of fine (PM) and coarse (PM) particles were assessed at 46 locations, including urban traffic, urban community, urban background, and desert locations. Crustal enrichment factors (EFs), roadside enrichments (REs), and bivariate correlation analysis revealed that Ba, Cr, Cu, Mo, Pd, Sb, Zn, and Zr were associated with traffic emissions in both PM and PM, while Fe, Li, Mn, and Ti were affected by traffic emissions mostly in PM. The concentrations of Ba, Cu, Mo, Sb, Zr (brake wear tracers), Pd (tailpipe tracer), and Zn (associated with tire wear) were higher at urban traffic sites than urban background locations by factors of 2.6-4.6. Both PM and PM elements showed large spatial variations, indicating the presence of diverse emission sources across sampling locations. Principal component analysis extracted four source factors that explained 88% of the variance in the PM elemental concentrations, and three sources that explained 86% of the variance in the PM elemental concentrations. Based on multiple linear regression analysis, the contribution of traffic emissions (27%) to PM was found to be higher than mineral dust (23%), marine aerosol (18%), and industrial emissions (8%). On the other hand, mineral dust was the dominant source of PM with 45% contribution, followed by marine aerosol (22%), and traffic emissions (19%). This study provides novel insight into the spatial variation of traffic-related elements in a large metropolitan area.
颗粒物（PM）的无机成分，尤其是过渡金属，已被证明对 PM 毒性有贡献。本研究旨在研究大洛杉矶地区 PM 元素的空间分布及其潜在来源。在 46 个地点评估了细颗粒物（PM）和粗颗粒物（PM）的质量浓度和详细元素组成，包括城市交通、城市社区、城市背景和沙漠地区。地壳富集因子（EFs）、路边富集（REs）和双变量相关分析表明，Ba、Cr、Cu、Mo、Pd、Sb、Zn 和 Zr 与 PM 和 PM 中的交通排放有关，而 Fe、Li、Mn 和 Ti 主要受 PM 中交通排放的影响。Ba、Cu、Mo、Sb、Zr（制动磨损示踪剂）、Pd（排气管示踪剂）和 Zn（与轮胎磨损有关）在城市交通站点的浓度比城市背景站点高 2.6-4.6 倍。PM 和 PM 元素都表现出较大的空间变化，表明在采样地点存在多种排放源。主成分分析提取了四个源因子，它们解释了 PM 元素浓度变化的 88%，三个源因子解释了 PM 元素浓度变化的 86%。基于多元线性回归分析，发现交通排放（27%）对 PM 的贡献高于矿物质尘埃（23%）、海洋气溶胶（18%）和工业排放（8%）。另一方面，矿物质尘埃是 PM 的主要来源，占 45%，其次是海洋气溶胶（22%）和交通排放（19%）。本研究为大都会区交通相关元素的空间变化提供了新的见解。
