The relationship between the number of COVID-19 cases, meteorological variables, and particulate matter concentration in a medium-sized Brazilian city

Abstract

The COVID-19 disease was first identified at the end of 2019 and spread rapidly around the world in 2020. Its symptom includes an acute respiratory crisis and the disease has claimed millions of victims. According to the literature, the relationship between COVID-19 transmission, and climatic factors and air pollutants is still unclear. Therefore, studies aiming to clarify this correlation are essential. This study aims to determine the correlation between the number of COVID-19 cases, particulate matter (PM) concentration, and meteorological variables in the city of Limeira, Brazil. The statistical analyses used were a generalized model with gamma distribution, Spearman’s correlation, and cluster analysis, followed by the Mann-Whitney test. The variables included were rainfall, temperature, wind speed, relative humidity, and atmospheric pressure, in addition to social distancing compliance rate, dummy variables for business opening flexibility, and the weekday. The concentration of the coarse inhalable particulate matter (PM10) fraction showed an inverse correlation with relative humidity, rainfall, and pressure. The Total Suspended Particulate matter (TSP) had an inverse correlation with relative humidity, rainfall, weekends, and social distancing compliance rate. A correlation was also found between the number of COVID-19 cases and pressure, PM10, and TSP. Finally, the calculated relative risk showed that the reduction in PM10 concentrations directly affects health, which implies an estimate of almost 13 deaths avoided in Limeira, during the pandemic. The results obtained provide important information as to improving air quality and strategies to contain COVID-19 transmission. Besides, albeit on a small scale, they confirm the relationship between the social distancing compliance rate, PM concentration, and COVID-19 cases.