Concentration of environmental fungal and bacterial bioaerosols during the monsoon season

Abstract

a b s t r a c tRain has been known to remove aerosol particles in air environments. The aerosol particles were captured and removed from the air by rain and the concentration of aerosol particles significantly decreased after rain events. Therefore, rain is regarded as having a good effect on air environments in terms of the respiratory health of the general public. However, humid environments produced by long-term rain events such a monsoon may be a sufficient condition for the growth of microorganisms and vibrations because of the splashing of droplets may facilitate the aerosolization of ground microorganisms. We therefore hypothesize that the rain may increase concentrations of bioaerosols in outdoor air environments, thereby possibly influencing respiratory diseases.To verify this hypothesis, at the initial stepwise approach, we measured the concentration of airborne biological particles before, after, and during rain in a monsoon season. The measurement data of the concentration of fungal particles and bacterial particles show quantitatively that the bioaerosol concentrations during the rain event are several times higher than the concentration of the bioaerosols in the condition of no rain.

Dynamics (seasonal and intra-diurnal) of air-borne fungal spore population of Doha area, Qatar

“…During drier years, a higher fungal spores in the air was reported (Pakpour et al, 2015) Rainfall might acts as a vacuum cleaner which clean the air by wet deposition mechanism and thus fungal spores are forced to settle down on the ground or another surfaces (Katial et al, 1997;Polymenakou, 2012).Contrary results were noted by Abu-Dieyeh et al (2010) who recorded the highest colonies count events post the heaviest precipitation and moderate temperature conditions, in Zarqa area, Jordan (Arid Irrano-terranean climate). Heo et al (2014) agreed with Abu-Dieyeh et al, (2010), they found the concentration of fungal bioaersols was much higher during rainy season than in non-rainy days. In such studies, the positive correlation between fungal bioaerosol's concentrations and rain was due to the fact that rain helps creating an environment of required moisture level for better fungal vegetation process, and due to the absence or reduction in solar radiation as well.…”

Analysis of Microbial Air Quality in the Surrounding Hospital’s Wastewater Treatment Plants in Jakarta, Indonesia

“…The data measurement of bioaerosol in WWTP showed varying results ( It was found that the concentration of bacteria and fungi was higher during rainy days due to higher air humidity. According to a research, the concentration of bioaerosol in bacteria and fungi during rainy season will be three to seven times higher than that of in normal dry (not raining) condition [13]. As for this research, the average concentration of bioaerosol in bacteria increased three to fifteen times during the rainy season and two to five times in fungi during the dry season.…”

Why Does Rain Increase the Concentrations of Environmental Bioaerosols during Monsoon?

“…We can normally observe clean ambient air environments and a clearer sky after rain events. However, a recent study reported an interesting and unexpected experimental result (Heo et al, 2014). As expected, rain decreased the PM10 concentration of the ambient environments; however, rain events increased the concentrations of airborne microorganisms in ambient air environments.…”

“…Airborne microorganisms, termed bioaerosols, are a type of aerosol particle (Hinds, 1999;Lee, 2011), but they did not follow the behaviors of other non-biological aerosol particles during rain events. The study showed that the concentrations of culturable fungal and bacterial bioaerosols during rain events were seven times and three times higher than at times without rain, respectively (Heo et al, 2014). In the same period, PM10 concentrations strongly decreased during rain events.…”

“…In the same period, PM10 concentrations strongly decreased during rain events. To explain this phenomenon, several hypotheses were proposed: 1) raindrops carried the microorganisms from higher altitude environments to ground-level environments; 2) the rainclouds decreased UV irradiation, which prevented the inactivation of culturable bioaerosols; 3) the splashing effects of raindrops propelled microorganisms on the ground into the surrounding air environment; and 4) the increased relative humidity during rain enhanced the sampling efficiency of the biosampler for culturable bioaerosols and might have generated adequate environments for the growth of microorganisms (Pasanen et al, 1991;Frankel et al, 2012;Heo et al, 2014). In the current study, we tried to test and evaluate each hypothesis by measuring bioaerosols in various environmental conditions.…”