Department of Chemical and Environmental Engineering, University of Arizona, PO BOX 210011, Tucson, AZ 85721, USA.
Department of Chemical and Environmental Engineering, University of Arizona, PO BOX 210011, Tucson, AZ 85721, USA; Department of Hydrology and Atmospheric Sciences, University of Arizona, PO BOX 210011, Tucson, AZ 85721, USA.
Sci Total Environ. 2019 Feb 15;651(Pt 2):1776-1787. doi: 10.1016/j.scitotenv.2018.10.086. Epub 2018 Oct 8.
This study examines co-located aerosol and precipitation chemistry data between 2010 and 2016 at Pinnacles National Monument ~65 km east of the coastline in central California. Positive matrix factorization analysis of the aerosol composition data revealed seven distinct pollutant sources: aged sea salt (25.7% of PM), biomass burning (24.2% of PM), fresh sea salt (15.0% of PM), secondary sulfate (11.7% of PM), dust (10.0% of PM), vehicle emissions (8.2% of PM), and secondary nitrate (5.2% of PM). The influence of meteorology and transport on monthly patterns of PM composition is discussed. Only secondary sulfate exhibited a statistically significant change (a reduction) over time among the PM source factors. In contrast, PM exhibited a significant increase most likely due to dust influence. Monthly profiles of precipitation chemistry are summarized showing that the most abundant species in each month was either SO, NO, or Cl. Intercomparisons between the precipitation and aerosol data revealed several features: (i) precipitation pH was inversely related to factors associated with more acidic aerosol constituents such as secondary sulfate and aged sea salt, in addition to being reduced by uptake of HNO in the liquid phase; (ii) two aerosol source factors (dust and aged sea salt) and PM exhibited a positive association with Ca in precipitation, suggestive of directly emitted aerosol types with larger sizes promoting precipitation; and (iii) sulfate levels in both the aerosol and precipitation samples analyzed were significantly correlated with dust and aged sea salt PMF factors, pointing to the partitioning of secondary sulfate to dust and sea salt particles. The results of this work have implications for the region's air quality and hydrological cycle, in addition to demonstrating that the use of co-located aerosol and precipitation chemistry data can provide insights relevant to aerosol-precipitation interactions.
本研究考察了 2010 年至 2016 年期间位于加利福尼亚州中部海岸以东约 65 公里的尖顶国家纪念碑的气溶胶和降水化学数据。对气溶胶成分数据的正矩阵因子分析揭示了七个不同的污染源：老化的海盐（占 PM 的 25.7%）、生物质燃烧（占 PM 的 24.2%）、新鲜的海盐（占 PM 的 15.0%）、次生硫酸盐（占 PM 的 11.7%）、灰尘（占 PM 的 10.0%）、机动车排放（占 PM 的 8.2%）和次生硝酸盐（占 PM 的 5.2%）。讨论了气象和传输对 PM 成分月变化模式的影响。在 PM 源因子中，只有次生硫酸盐随着时间的推移呈现出统计学上的显著变化（减少）。相比之下，由于灰尘的影响，PM 表现出明显的增加。总结了降水化学的月度分布情况，表明每个月最丰富的物质都是 SO、NO 或 Cl。降水和气溶胶数据之间的相互比较揭示了几个特征：（i）降水 pH 值与更酸性的气溶胶成分（如次生硫酸盐和老化的海盐）相关的因子呈负相关，此外还因液相中 HNO 的吸收而降低；（ii）两个气溶胶源因子（灰尘和老化的海盐）和 PM 与降水 Ca 呈正相关，表明具有较大粒径的直接排放的气溶胶类型促进了降水；（iii）分析的气溶胶和降水样本中的硫酸盐水平与灰尘和老化的海盐 PMF 因子显著相关，表明次生硫酸盐向灰尘和海盐颗粒分配。这项工作的结果对该地区的空气质量和水文循环有影响，此外还表明使用共存的气溶胶和降水化学数据可以提供与气溶胶-降水相互作用相关的见解。
