Longitudinal survey of microbiome associated with particulate matter in a megacity

Abstract

Background: While the physical and chemical properties of airborne particulate matter (PM) have been extensively studied, their associated microbiome remains largely unexplored. Here, we performed a longitudinal metagenomic survey of 106 samples of airborne PM 2.5 and PM 10 in Beijing over a period of 6 months in 2012 and 2013, including those from several historically severe smog events.Results: We observed that the microbiome composition and functional potential were conserved between PM 2.5 and PM 10 , although considerable temporal variations existed. Among the airborne microorganisms, Propionibacterium acnes, Escherichia coli, Acinetobacter lwoffii, Lactobacillus amylovorus, and Lactobacillus reuteri dominated, along with several viral species. We further identified an extensive repertoire of genes involved in antibiotic resistance and detoxification, including transporters, transpeptidases, and thioredoxins. Sample stratification based on Air Quality Index (AQI) demonstrated that many microbial species, including those associated with human, dog, and mouse feces, exhibit AQI-dependent incidence dynamics. The phylogenetic and functional diversity of air microbiome is comparable to those of soil and water environments, as its composition likely derives from a wide variety of sources.Conclusions: Airborne particulate matter accommodates rich and dynamic microbial communities, including a range of microbial elements that are associated with potential health consequences.

The Potential role of Particulate Matter in the Spreading of COVID-19 in Northern Italy: First Evidence-based Research Hypotheses

“…Our findings showed that high frequency of PM 10 concentration peaks (exceeding 50 µg/m 3 ) result in a spread acceleration of COVID-19, suggesting a "boost effect" for the viral infectivity. We found significance differences both in PM 10 The other hypothesis is that PM could act as a carrier for droplet nuclei, triggering a boost effect on the spread of the virus ( Figure 5). It could be possible to look at the airborne route of transmission, and specifically to particulate matter, as a "highway " for the viral diffusion, in which the droplet nuclei emitted by the exhalations are stabilized in the air through the coalescence of aerosol with the PM at high concentrations in stability conditions.…”

“…Based on the available literature [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19], there is enough evidence to consider the airborne route, ant specifically the role of particulate matter, as a possible additional infection "boosting" factor for interpreting the anomalous COVID-19 outbreaks observed in the Northern Italy -known to be one of the European areas characterized by the highest PM concentration [1]. Airborne transmission is certainly more effective in indoor environments, with little ventilation, but it must be considered that the Po Valley, by its atmospheric stability, closely resembles a confined environment and that long-distance virus transport is favored by high concentration of dusts.…”

“…PM 10 daily concentration levels were collected by the official air quality monitoring stations of the Regional Environmental Protection Agencies, ARPA), publicly available on their websites. The number of PM 10 infected people for each Province from February 24 th to March 13 th (the date when the lockdown was decided) was that reported on the official Government website, updated with daily frequency [24]. PM 10 exceedances were collected between February 9 th and February 29 th , taking into account the lag period, which is the average time elapsed between the initial infection and the diagnosis.…”

“…At the same time, a number of studies have shown that airborne transmission route could spread viruses even further the close contact with infected people [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Paules et al (2020) highlighted that -besides close distance contacts -airborne transmission of SARS-CoV can also occur [5].…”

“…Relationship between the PM10 daily limit value exceedances and the COVID-19 cases rati over Italian Provinces population. (a) Scatterplot on semi-logarithmic scale relating the proportion COVID-19 cases of Northern (gray squares) and Southern (black bullets) Italian Provinces populativersus the average of PM10 daily limit value exceedances. The dashed binomial (logistic) regression characterized by an increasing slope of 0.25 (p < 0.001).…”