key: cord-0906807-wvp362qj authors: Hou, Chang‐kai; Qin, Ya‐fei; Wang, Grace; Liu, Quan‐lei; Yang, Xin‐yu; Wang, Hao title: Impact of a long‐term air pollution exposure on the case fatality rate of COVID‐19 patients—A multicity study date: 2021-02-15 journal: J Med Virol DOI: 10.1002/jmv.26807 sha: 0373c8cdd4d0ba721ca903a6dc5d20f9696e7e6b doc_id: 906807 cord_uid: wvp362qj Evidence in the literature suggests that air pollution exposure affects outcomes of patients with COVID‐19. However, the extent of this effect requires further investigation. This study was designed to investigate the relationship between long‐term exposure to air pollution and the case fatality rate (CFR) of patients with COVID‐19. The data on air quality index (AQI), PM2.5, PM10, SO(2), NO(2), and O(3) from 14 major cities in China in the past 5 years (2015–2020) were collected, and the CRF of COVID‐19 patients in these cities was calculated. First, we investigated the correlation between CFR and long‐term air quality indicators. Second, we examined the air pollutants affecting CFR and evaluated their predictive values. We found a positive correlation between the CFR and AQI (1, 3, and 5 years), PM2.5 (1, 3, and 5 years), and PM10 (1, 3, and 5 years). Further analysis indicated the more significant correlation for both AQI (3 and 5 years) and PM2.5 (1, 3, and 5 years) with CFR, and moderate predictive values for air pollution indicators such as AQI (1, 3, and 5 years) and PM2.5 (1, 3, and 5 years) for CFR. Our results indicate that long‐term exposure to severe air pollution is associated with higher CFR of COVID‐19 patients. Air pollutants such as PM2.5 may assist with the prediction of CFR for COVID‐19 patients. The novel coronavirus was first reported in Wuhan, China, in December 2019, 1,2 and then spread rapidly worldwide. Organization (WHO) in March 2020. 3 Previous studies have found that the morbidity and mortality of COVID-19 patients were related to their general health or presence of comorbidities, such as gender, age, hypertension, diabetes, and obesity. [4] [5] [6] [7] [8] Air pollution can stimulate respiratory and systemic inflammatory responses, and the primary affected organ of both COVID-19 and air pollution is the respiratory system. It has been demonstrated that air pollution increases the incidence of airway inflammation and lung diseases. 9,10 Recent research has indicated that short-term exposure to air pollution increases the risk of COVID-19 infection, [11] [12] [13] and the relationship between the longterm air pollution exposure and the outcome of patients with COVID-19 has been investigated but no consensus has been reached. 14, 15 In this study, the objective was to investigate the effects of long-term exposure to air pollution on the case fatality rate A total of 14 cities were included in this study ( Figure 1 and Table S1 ). The trend of several air pollution indicators in these 14 cities over the past 5 years is shown in As shown in Figure 3 and Figure 1 . As compared with the low CFR group, the AQI (3 and 5 years) and PM2.5 (1, 3, and 5 years) were significantly higher in the high CFR group (p < .05) ( ROC curve was used to calculate the predictive value of air pollutants to CFR, and it showed the area under the curve of In this multicity study, we have estimated the association be- outcomes between regions. Public health authorities should focus more on these vulnerable populations, who are exposed to severe long-term air pollution. Previous studies have shown that living environments play an important role in the transmission and outcomes of major viral diseases, namely severe acute respiratory syndrome 16 and H1N1 influenza. 17 The role of the atmospheric environment in COVID-19 cases is not yet fully understood. 18 and mortality rates in the United States; they found that long-term exposure to NO 2 may enhance the susceptibility to severe COVID-19 outcomes. In the 14 cities researched in this study, the levels of the most air pollutants, such as NO 2 , PM2.5, and PM10, gradually decreased over the past five years (Figure 3 ), which may be attributed to the increased awareness of environmental protection in China. However, considering that the impact Abbreviation: AQI, air quality index. a Indicates that this data is statistically significant; "(1 year)" is the abbreviation of "Average in the past year"; "(3 years)" is the abbreviation of "Average in the past 3 years"; "(5 years)" is the abbreviation of "Average in the past 5 Abbreviations: AQI, air quality index; CFR, case fatality rate. *Indicates that this data is statistically significant; "(1 year)" is the abbreviation of "Average in the past year"; "(3 years)" is the abbreviation of "Average in the past 3 years"; "(5 years)" is the abbreviation of "Average in the past 5 years". Abbreviations: AQI, air quality index; ROC, receiver operating characteristic curve. a Indicates that this data is statistically significant; "(1 year)" is the abbreviation of "Average in the past year"; "(3 years)" is the abbreviation of "Average in the past 3 years"; "(5 years)" is the abbreviation of "Average in the past 5 years." Clinical features of patients infected with 2019 novel coronavirus in Wuhan Early transmission dynamics in Wuhan, China, of novel coronavirus-infected pneumonia 4 ROC curves showing the ability of air quality indicators to predict the CFR. 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A Nationwide Analysis in 272 Chinese Cities Assessing nitrogen dioxide (NO2) levels as a contributing factor to coronavirus (COVID-19) fatality The authors would like to show their respect for all the hospital staff for their hard work and efforts to combat the COVID-2019. The anthors declare that there are no conflict of interests. The peer review history for this article is available at http://publons. com/publon/10.1002/jmv.26807. Data available on request from the authors.