Air pollutants, climatic factor and their interactions influence the transmission of COVID-19 cases: Evidence from a global south megacity

Abstract:

A novel coronavirus disease with flu-like symptoms evolved in Wuhan, China in December 2019 that shortly spread globally and brought public health crises to the people. There is emerging evidence that climatic factors have significant effects on the spreading of COVID-19. However, little research has been done on the impact of air pollutants and their interactions with climate on COVID-19 transmission. Therefore, this study aims to examine the association particulate matter (PM2.5), climatic factors, and their interactive effect influences the COVID-19 in the global south. This study takes the Dhaka megacity of Bangladesh as a case city.

Data on daily confirmed cases of Bangladesh from April 4, 2020, to May 24, 2020, were collected from Worldometer website. The daily PM2.5 data of capital city (Dhaka) for the same study periods were collected from the online portal (https://aqicn.org/city) which provides US EPA Standard AQI data. Temperature and Relative humidity were included as confounding variables. The data of daily mean temperature and relative humidity for Dhaka city for the same duration were collected from the NOAA website. To estimate the delayed effect, we considered 21-days moving averages of all climate factors and PM2.5. Spearman correlation was conducted to examine the relationship between two variables. As our health outcome is count variable, we applied negative binomial regression model that deals with over-dispersed data to determine the association between air pollutants and COVID-19 cases.

In univariate analysis, PM2.5 at 21-days (r = 0.037, P = 0.03) of moving averages showed positive association with COVID-19 cases in Bangladesh. After adjusting confounding variables, PM2.5 showed a negative association with COVID-19 cases. However, relative humidity of 21-days moving average (r = 0.076, P = 0.01) showed positive association with COVID-19 cases. In terms of interaction, PM2.5 and temperature interactions were associated with COVID-19 cases. The findings show that air pollutants, climatic factors, and their interactions all associated with COVID-19 cases.