SARS-CoV-2 RNA was not detected in 44 outdoor PM samples.
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The probability of detecting SARS-CoV-2 RNA in airborne samples is considered low.
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Monitoring the presence of SARS-CoV-2 RNA on PMs does not represent an efficient early indicator of virus transmission.
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Monitoring SARS-CoV-2 RNA on PM does not represent an early indicator of the pandemic's recurrence.
Abstract
The airborne transmission of SARS-CoV-2, the etiologic agent of the current COVID-19 pandemic, has been hypothesized as one of the primary routes of transmission. Current data suggest a low probability of airborne transmission of the virus in open environments and a higher probability in closed ones, particularly in hospitals or quarantine facilities. However, the potential diffusion of the virus in open environments, especially using particulate matter (PM) as a transport carrier, generated concern in the exposed populations. Several authors found a correlation between the exceeding of the PM10 concentration limits in some Italian cities and the prevalence of Covid-19 cases detected in those areas. This study investigated the potential presence of SARS-COV-2 RNA on a representative series of PM samples collected in the province of Padua in Northeastern Italy during the first wave of COVID pandemic. Forty-four samples of PM2.5 and PM10 were collected between February 24 and March 9, 2020 and analyzed with RT-qPCR for SARS-CoV-2 RNA. The experimental results did not indicate the presence of SARS-CoV-2 RNA in the outdoor PMs, thus confirming the low probability of virus airborne transmission through PM.
