Exposure to particulate matter: Direct and indirect role in the COVID-19 pandemic

Knowing the transmission factors and the natural environment that favor the spread of a viral infection is crucial to stop outbreaks and develop effective preventive strategies. This work aims to evaluate the role of Particulate Matter (PM) in the COVID-19 pandemic, focusing especially on that of PM as a vector for SARS-CoV-2. Exposure to PM has been related to new cases and to the clinical severity of people infected by SARS-CoV-2, which can be explained by the oxidative stress and the inflammatory response generated by these particles when entering the respiratory system, as well as by the role of PM in the expression of ACE-2 in respiratory cells in human hosts. In addition, different authors have detected SARS-CoV-2 RNA in PM sampled both in outdoor and indoor environments. The results of various studies lead to the hypothesis that the aerosols emitted by an infected person could be deposited in other suspended particles, sometimes of natural but especially of anthropogenic origin, that form the basal PM. However, the viability of the virus in PM has not yet been demonstrated. Should PM be confirmed as a vector of transmission, prevention strategies ought to be adapted, and PM sampling in outdoor environments could become an indicator of viral load in a specific area.

Automated summary

Understanding the role of Particulate Matter (PM) in the COVID-19 pandemic is important for preventing outbreaks. Exposure to PM has been linked to new cases and severity of SARS-CoV-2 infection. PM can cause oxidative stress and inflammation in the respiratory system, and it plays a role in the expression of ACE-2 in respiratory cells. SARS-CoV-2 RNA has also been detected in PM samples from indoor and outdoor environments. If PM is confirmed as a transmission vector, prevention strategies may need to be adapted and PM sampling could indicate viral load in specific areas.