Division of Environmental Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk, 37673, South Korea.
School of the Environment, Yale University, New Haven, CT, 06511, USA.
Environ Res. 2023 Jan 1;216(Pt 1):114461. doi: 10.1016/j.envres.2022.114461. Epub 2022 Sep 28.
California experienced extreme and prolonged drought conditions during the early 2010s. To date, little is known regarding the influence of drought on air quality. Our study quantified site-specific associations between drought (defined by the Standardized Precipitation-Evapotranspiration Index; SPEI) and daily maximum 8-h ozone (O) concentrations for California, USA, and then pooled these associations for the years 2009-2015. Overall, ambient O concentration was higher during droughts by 1.18 ppb (95% confidence interval (CI) = 1.00-1.36). The sensitivity of O to drought was greater during the warm season than during the cool season (1.73 ppb versus 0.79 ppb higher O during droughts) with substantial regional variation. In a pooled analysis with meteorological parameters as potential effect modifiers, the spatial heterogeneity of drought-O associations was explained strongly by average relative humidity for each season (71.9% (warm season) and 73.4% (cool season) of the drought-O associations explained), followed by the drought-related changes in relative humidity (47.6% (warm season)) and temperature (53.6% (cool season)). The pooled regression further identified regions susceptible for drought-related O increases as those with relatively low average relative humidity (10-25 percentiles or 44.3-47.3%) and larger drought-related decrease in relative humidity and increase in temperature. As the drought events are projected to occur with increased frequency and intensity in the era of climate change, the excess health burdens from O exposures attributed to the projected drought events need to be taken into account when allocating air quality and health resources. The impacts of O on health during droughts would confound the health burdens from the drought itself.
加利福尼亚州在 21 世纪 10 年代初经历了极端和长期的干旱。迄今为止，人们对干旱对空气质量的影响知之甚少。我们的研究量化了干旱（由标准化降水蒸散指数定义）与美国加利福尼亚州每日最大 8 小时臭氧（O）浓度之间的特定地点关联，然后汇总了 2009-2015 年的数据。总的来说，在干旱期间，环境 O 浓度高出 1.18 ppb（95%置信区间[CI]为 1.00-1.36）。与凉爽季节相比，温暖季节 O 对干旱的敏感性更高（干旱期间 O 浓度高出 1.73 ppb，而高出 0.79 ppb），且存在明显的区域差异。在一项与气象参数作为潜在效应修饰剂的汇总分析中，每个季节的平均相对湿度强烈解释了干旱-O 关联的空间异质性（温暖季节和凉爽季节的干旱-O 关联分别解释了 71.9%和 73.4%），其次是与干旱相关的相对湿度变化（温暖季节为 47.6%）和温度变化（凉爽季节为 53.6%）。汇总回归进一步确定了那些相对平均相对湿度较低（10-25%分位数或 44.3-47.3%）且与干旱相关的相对湿度降低和温度升高幅度较大的区域容易受到干旱相关 O 增加的影响。由于在气候变化时代，干旱事件预计会更加频繁和剧烈地发生，因此在分配空气质量和健康资源时，需要考虑到与预测的干旱事件相关的 O 暴露所导致的额外健康负担。干旱期间 O 对健康的影响会使干旱本身造成的健康负担复杂化。
