PM_2.5 Pollution Strongly Predicted COVID-19 Incidence in Four High-Polluted Urbanized Italian Cities during the Pre-Lockdown and Lockdown Periods

• Main Authors: Ourania S. Kotsiou, Vaios S. Kotsios, Ioannis Lampropoulos, Thomas Zidros, Sotirios G. Zarogiannis, Konstantinos I. Gourgoulianis
• Format: Article
• Language: English
• Published: MDPI AG 2021-05-01
• Series: International Journal of Environmental Research and Public Health
• Subjects: air pollution; coronavirus disease 2019; fine particulate matter; humidity; Italy; temperature
• Online Access: https://www.mdpi.com/1660-4601/18/10/5088

Background: The coronavirus disease in 2019 (COVID-19) heavily hit Italy, one of Europe’s most polluted countries. The extent to which PM pollution contributed to COVID-19 diffusion is needing further clarification. We aimed to investigate the particular matter (PM) pollution and its correlation with COVID-19 incidence across four Italian cities: Milan, Rome, Naples, and Salerno, during the pre-lockdown and lockdown periods. Methods: We performed a comparative analysis followed by correlation and regression analyses of the daily average PM₁₀, PM_2.5 concentrations, and COVID-19 incidence across four cities from 1 January 2020 to 8 April 2020, adjusting for several factors, taking a two-week time lag into account. Results: Milan had significantly higher average daily PM₁₀ and PM_2.5 levels than Rome, Naples, and Salerno. Rome, Naples, and Salerno maintained safe PM₁₀ levels. The daily PM_2.5 levels exceeded the legislative standards in all cities during the entire period. PM_2.5 pollution was related to COVID-19 incidence. The PM_2.5 levels and sampling rate were strong predictors of COVID-19 incidence during the pre-lockdown period. The PM_2.5 levels, population’s age, and density strongly predicted COVID-19 incidence during lockdown. Conclusions: Italy serves as a noteworthy paradigm illustrating that PM_2.5 pollution impacts COVID-19 spread. Even in lockdown, PM_2.5 levels negatively impacted COVID-19 incidence.