Department of Chemical and Environmental Engineering, University of Arizona , Tucson, Arizona 85721, United States.
Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University , Raleigh, North Carolina 27695, United States.
Environ Sci Technol. 2017 Aug 15;51(16):9013-9021. doi: 10.1021/acs.est.7b02039. Epub 2017 Jul 27.
This work examines particulate chloride (Cl) and bromide (Br) depletion in marine aerosol particles influenced by wildfires at a coastal California site in the summers of 2013 and 2016. Chloride exhibited a dominant coarse mode due to sea salt influence, with substantially diminished concentrations during fire periods as compared to nonfire periods. Bromide exhibited a peak in the submicrometer range during fire and nonfire periods, with an additional supermicrometer peak in the latter periods. Chloride and Br depletions were enhanced during fire periods as compared to nonfire periods. The highest observed %Cl depletion occurred in the submicrometer range, with maximum values of 98.9% (0.32-0.56 μm) and 85.6% (0.56-1 μm) during fire and nonfire periods, respectively. The highest %Br depletion occurred in the supermicrometer range during fire and nonfire periods with peak depletion between 1.8-3.2 μm (78.8% and 58.6%, respectively). When accounting for the neutralization of sulfate by ammonium, organic acid particles showed the greatest influence on Cl depletion in the submicrometer range. These results have implications for aerosol hygroscopicity and radiative forcing in areas with wildfire influence owing to depletion effects on composition.
本研究考察了 2013 年和 2016 年加利福尼亚沿海地区野火对海洋气溶胶颗粒中颗粒态氯（Cl）和溴（Br）消耗的影响。Cl 主要以粗模态存在，由于海盐的影响，其浓度在火灾期间显著低于非火灾期间。Br 在火灾和非火灾期间均在亚微米范围内出现峰值，而在后者期间还出现了超微米峰值。与非火灾期间相比，火灾期间的 Cl 和 Br 消耗增强。观察到的最高 %Cl 消耗出现在亚微米范围内，火灾和非火灾期间的最大消耗值分别为 98.9%（0.32-0.56μm）和 85.6%（0.56-1μm）。最高的 %Br 消耗发生在火灾和非火灾期间的超微米范围内，在 1.8-3.2μm 范围内的消耗峰值分别为 78.8%和 58.6%。当考虑到硫酸盐被氨中和时，有机气溶胶颗粒对亚微米范围内的 Cl 消耗的影响最大。由于组成上的消耗效应，这些结果对受野火影响地区的气溶胶吸湿性和辐射强迫具有重要意义。
