Effects of PM2.5, PM10, and Environmental Factors in Spreading COVID-19: A Case Study of Delhi, India.

The inhalation of particulate matter (PM) has been linked to various respiratory illnesses, including asthma, chronic obstructive pulmonary disease, and cancer. The COVID-19 pandemic has heightened concerns about PM as a possible route of virus transmission through airborne particles. This study investigated the impact of lockdown on particulate matter and mass-segregated PM (PM2.5 and PM10) deposition in human lungs. In this study, the daily average concentration of particulate matter (PM2.5 and PM10) was observed from March 22 to May 15, 2021, and grouped into two categories: before and during lockdown. The lockdown resulted in a 1.6% decrease in PM2.5 concentration and a 15% decrease in PM10 concentration. Ground-level particulate matter concentrations were found to be positively correlated with daily new COVID-19 cases and daily deaths during the lockdown period. Meteorological temperature was found to be positively associated with daily cases and daily deaths due to COVID-19. The noncarcinogenic risk was calculated by hazard quotient (HQ) with annual daily dose (ADD), and it exceeded the target value of 1 in almost all cases. Analysis of airway geometry and mass deposition indicated that mass deposition was reduced by 25% and 13% for PM2.5 and PM10 , respectively. Therefore, ambient air pollution may be considered to be a major cofactor for the high death rate and number of daily cases during the pandemic. Based on the obtained results, the study recommends implementing effective pollution mitigation strategies to reduce the risk of respiratory illnesses and disease transmission through the air as a medium. [ABSTRACT FROM AUTHOR]