Aguilera Rosana, Gershunov Alexander, Ilango Sindana D, Guzman-Morales Janin, Benmarhnia Tarik
Scripps Institution of Oceanography University of California San Diego La Jolla CA USA.
Department of Family Medicine and Public Health University of California San Diego La Jolla CA USA.
Geohealth. 2020 Jan 11;4(1):e2019GH000225. doi: 10.1029/2019GH000225. eCollection 2020 Jan.
Fine particulate matter (PM) raises human health concerns since it can deeply penetrate the respiratory system and enter the bloodstream, thus potentially impacting vital organs. Strong winds transport and disperse PM, which can travel over long distances. Smoke from wildfires is a major episodic and seasonal hazard in Southern California (SoCal), where the onset of Santa Ana winds (SAWs) in early fall before the first rains of winter is associated with the region's most damaging wildfires. However, SAWs also tend to improve visibility as they sweep haze particles from highly polluted areas far out to sea. Previous studies characterizing PM in the region are limited in time span and spatial extent, and have either addressed only a single event in time or short time series at a limited set of sites. Here we study the space-time relationship between daily levels of PM in SoCal and SAWs spanning 1999-2012 and also further identify the impact of wildfire smoke on this relationship. We used a rolling correlation approach to characterize the spatial-temporal variability of daily SAW and PM. SAWs tend to lower PM levels, particularly along the coast and in urban areas, in the absence of wildfires upwind. On the other hand, SAWs markedly increase PM in zip codes downwind of wildfires. These empirical relationships can be used to identify windows of vulnerability for public health and orient preventive measures.
细颗粒物（PM）引发了人们对人类健康的担忧，因为它可以深入呼吸系统并进入血液，从而可能影响重要器官。强风会输送和扩散细颗粒物，这些细颗粒物可以远距离传播。野火产生的烟雾是南加州（SoCal）主要的偶发性和季节性危害，在那里，初冬第一场雨之前初秋的圣安娜风（SAWs）的出现与该地区最具破坏性的野火有关。然而，圣安娜风在将雾霾颗粒从高度污染地区吹向大海远处时，也往往会改善能见度。此前对该地区细颗粒物特征的研究在时间跨度和空间范围上都很有限，要么只针对某一时刻的单一事件，要么是在有限的一组地点进行短时间序列研究。在此，我们研究了1999年至2012年期间南加州细颗粒物日水平与圣安娜风之间的时空关系，并进一步确定野火烟雾对这种关系的影响。我们使用滚动相关方法来描述圣安娜风日和细颗粒物的时空变异性。在没有上游野火的情况下，圣安娜风往往会降低细颗粒物水平，尤其是在沿海地区和城市地区。另一方面，圣安娜风会显著增加野火下风方向邮政编码区域内的细颗粒物。这些经验关系可用于确定公共卫生的脆弱窗口期并指导预防措施。
