RT Journal Article
SR Electronic
T1 Potential role of particulate matter in the spreading of COVID-19 in Northern Italy: first observational study based on initial epidemic diffusion
JF BMJ Open
JO BMJ Open
FD British Medical Journal Publishing Group
SP e039338
DO 10.1136/bmjopen-2020-039338
VO 10
IS 9
A1 Leonardo Setti
A1 Fabrizio Passarini
A1 Gianluigi De Gennaro
A1 Pierluigi Barbieri
A1 Sabina Licen
A1 Maria Grazia Perrone
A1 Andrea Piazzalunga
A1 Massimo Borelli
A1 Jolanda Palmisani
A1 Alessia Di Gilio
A1 Emanuele Rizzo
A1 Annamaria Colao
A1 Prisco Piscitelli
A1 Alessandro Miani
YR 2020
UL http://bmjopen.bmj.com/content/10/9/e039338.abstract
AB Objectives A number of studies have shown that the airborne transmission route could spread some viruses over a distance of 2 meters from an infected person. An epidemic model based only on respiratory droplets and close contact could not fully explain the regional differences in the spread of COVID-19 in Italy. On March 16th 2020, we presented a position paper proposing a research hypothesis concerning the association between higher mortality rates due to COVID-19 observed in Northern Italy and average concentrations of PM10 exceeding a daily limit of 50 µg/m3.Methods To monitor the spreading of COVID-19 in Italy from February 24th to March 13th (the date of the Italian lockdown), official daily data for PM10 levels were collected from all Italian provinces between February 9th and February 29th, taking into account the maximum lag period (14 days) between the infection and diagnosis. In addition to the number of exceedances of the daily limit value of PM10, we also considered population data and daily travelling information for each province.Results Exceedance of the daily limit value of PM10 appears to be a significant predictor of infection in univariate analyses (p<0.001). Less polluted provinces had a median of 0.03 infections over 1000 residents, while the most polluted provinces showed a median of 0.26 cases. Thirty-nine out of 41 Northern Italian provinces resulted in the category with the highest PM10 levels, while 62 out of 66 Southern provinces presented low PM10 concentrations (p<0.001). In Milan, the average growth rate before the lockdown was significantly higher than in Rome (0.34 vs 0.27 per day, with a doubling time of 2.0 days vs 2.6, respectively), thus suggesting a basic reproductive number R0>6.0, comparable with the highest values estimated for China.Conclusion A significant association has been found between the geographical distribution of daily PM10 exceedances and the initial spreading of COVID-19 in the 110 Italian provinces.