Globally, wildfires have seen remarkable increase in duration and size and have become a health hazard. In addition to vegetation and habitat destruction, rapid release of smoke, dust and gaseous pollutants in the atmosphere contributes to its short and long-term detrimental effects. Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has emerged as a public health concern worldwide that primarily target lungs and respiratory tract, akin to air pollutants. Studies from our lab and others have demonstrated association between air pollution and COVID-19 infection and mortality rates. However, current knowledge on the impact of wildfire-mediated sudden outburst of air pollutants on COVID-19 is limited. In this study, we examined the association of air pollutants and COVID-19 during wildfires burned during August-October 2020 in California, United States. We observed an increase in the tropospheric pollutants including aerosols (particulate matter [PM]), carbon monoxide (CO) and nitrogen dioxide (NO₂) by approximately 150%, 100% and 20%, respectively, in 2020 compared to the 2019. Except ozone (O₃), similar proportion of increment was noticed during the peak wildfire period (August 16 – September 15, 2020) in the ground PM_2.5, CO, and NO₂ levels at Fresno, Los Angeles, Sacramento, San Diego and San Francisco, cities with largest active wildfire area. We identified three different spikes in the concentrations of PM_2.5, and CO for the cities examined clearly suggesting wildfire-induced surge in air pollution. Fresno and Sacramento showed increment in the ground PM_2.5, CO and NO₂ levels, while San Diego recorded highest change rate in NO₂ levels. Interestingly, we observed a similar pattern of higher COVID-19 cases and mortalities in the cities with adverse air pollution caused by wildfires. These findings provide a logical rationale to strategize public health policies for future impact of COVID-19 on humans residing in geographic locations susceptible to sudden increase in local air pollution.

在全球范围内，野火的持续时间和规模显着增加，并已成为健康危害。除了植被和栖息地遭到破坏之外，大气中烟雾、灰尘和气态污染物的快速释放也造成了短期和长期的有害影响。严重急性呼吸系统综合症冠状病毒 2 (SARS-CoV-2) 已成为世界范围内的一个公共卫生问题，它主要针对肺部和呼吸道，类似于空气污染物。我们实验室和其他实验室的研究表明，空气污染与 COVID-19 感染和死亡率之间存在关联。然而，目前关于野火引发的空气污染物突然爆发对 COVID-19 影响的了解有限。在这项研究中，我们研究了 2020 年 8 月至 10 月美国加利福尼亚州发生的野火期间空气污染物与 COVID-19 的关联。我们观察到，与 2019 年相比，2020 年包括气溶胶（颗粒物 [PM]）、一氧化碳（CO）和二氧化氮（NO ₂ ）在内的对流层污染物分别增加了约 150%、100% 和 20%。除臭氧 (O ₃ ) 外，在野火高峰期（2020 年 8 月 16 日至 9 月 15 日），弗雷斯诺、洛杉矶、萨克拉门托、圣地亚哥和加利福尼亚州的地面 PM _2.5 、CO 和 NO ₂水平也出现了类似比例的增量。旧金山，拥有最大活跃野火面积的城市。我们在所检查的城市中发现了 PM _2.5和 CO 浓度的三个不同峰值，这清楚地表明野火引起的空气污染激增。弗雷斯诺和萨克拉门托的地面 PM _{2 含量有所增加。}如图5所示，CO和NO ₂水平变化，而圣地亚哥的NO ₂水平变化率最高。有趣的是，我们在因野火造成不良空气污染的城市中观察到了类似的 COVID-19 病例和死亡率较高的模式。这些发现为制定公共卫生政策战略提供了逻辑依据，以应对未来 COVID-19 对居住在容易受到当地空气污染突然增加影响的地理位置的人类的影响。