摘要：Despite significant strides to minimize lead in our air, water, soil, food, homes, workplaces, and consumer products, sporadic and systemic lead poisoning persists in industrial societies, e.g., the contemporary Flint (Michigan, USA) municipal water tragedy. Because lead exposure is cumulative, the sum of exposure from all sources, it is important to document and update potential community or neighborhood exposure levels from such environmental compartments as air, water, soil, food, and housing. Here we present ambient airborne lead levels in El Paso, Texas, USA, parsed by particulate matter (PM) size fraction, geography, and season. Dichotomous samplers at 8 stations collected PM continuously for 1-week periods for nearly 4 years. Overall, airborne annual lead exposure throughout El Paso County is low, well within US Environmental Protection Agency (EPA) guidelines. There is considerably more lead in the coarse fraction (PM10-PM2.5) than in the fine fraction (PM2.5 and lower), indicating decreased effective human exposures because the coarse fraction does not penetrate as deeply into the pulmonary system as finer particles. Re-entrained soil has previously been identified as the source of airborne lead in El Paso; the concentration of lead in the coarse PM is consistent with this observation. Seasonally, fall-winter lead levels are highest, due to PM trapping by temperature inversions, followed by spring and summer. Geospatially, higher lead levels characterize sampling stations in older and more commercial neighborhoods, also consistent with published maps of soil lead levels throughout the city and county. At present, airborne lead can be considered to be only a minor source of lead exposure for typical El Paso residents.
关键词：lead; air pollution; particulate matter; El Paso
