Since poor air quality affects human health in the short and long term, much research has been performed on indoor and outdoor aerosol exposure; however, there is a lack of specific data on the exposure and health risks of inhalable aerosols that contain bioaerosol in different environments of human life. To investigate the potential exposure to inhalable aerosols (in the monitoring of particulate matter (PM) based on R modeling, variations of PM depend on the ventilation system and bioaerosols based on size distribution) in various environments, the special viability and culturability of bioaerosols and their deposition doses in the respiratory system were evaluated. We conducted exposure assessments on inhalable aerosols in various indoor environments (childcare facilities, schools, commercial buildings, elderly and homes). The fractions of PM (PM10, PM4 and PM2.5) were investigated and, for the bioaerosol, the viability, culturability, inhalation daily dose and the deposited dose of the aerosol in the respiratory system were calculated to evaluate the human health effects. For two years, the distribution of the indoor PM concentration was high in all PM fractions in schools and commercial buildings, and low in the elderly and at homes. For airborne bacteria, the highest concentrations were shown in the childcare facility during the four seasons, while airborne fungi showed high concentrations in the buildings during the spring and summer, which showed significant differences from other investigated environments (between the buildings and elderly and homes: p < 0.05). The viability and culturability for the bioaerosol showed no significant difference in all environments, and the correlation between inhalable PM and bioaerosol obtained from the six-stage impactor showed that the coefficient of determination (R2) between coarse particles (PM10-2.5, the size of stage 2-3) and cultivable airborne bacteria ranged from 0.70 (elderly and homes) to 0.84 (school) during the summer season.

https://www.mdpi.com/1660-4601/17/6/1923/pdf

Human Inhalation Exposure to Aerosol and Health Effect: Aerosol Monitoring and Modelling Regional Deposited Doses

In the modern world, healthy habits and physical and mental fitness are more important than ever. A growing number of people participate in sports to improve their overall health. However, the conditions in which people exercise are seldom examined. It is obvious that the air in buildings, including sports facilities, can be contaminated with pathogenic microorganisms, causing infections and allergies. Our study was aimed at assessing microbial air quality inside several sports facilities (fitness room, martial arts room, swimming pool, sports hall, gym) and at a sports field. Another objective was to evaluate the antibiotic resistance of isolated Staphylococcus strains. Air samples were collected with MAS-100 sampler, using selective substrates. Antibiotic resistance of mannitol-positive staphylococci was assessed using a disk diffusion method in accordance with EUCAST recommendations. The results indicated large fluctuations in average concentrations of heterotrophic bacteria, ranging from 38 CFU m−3 (swimming pool) to 1036 CFU m−3 (sports hall). Generally, bacteria were more abundant inside the buildings, while fungi in the sports field (658 CFU m−3 on average). In all facilities, airborne fungal communities were dominated by the genus Cladosporium, followed by Penicillium, Fusarium and Acremonium. Alternaria and Aureobasidium constituted only a small percentage of isolated molds. We recorded only low concentrations of mannitol-positive staphylococci (on average ranging from 1 CFU m−3 at the swimming pool and sports field to 9 CFU m−3 in the martial arts room). Of all isolated Staphylococcus strains, 73% were resistant to benzopenicillin, while more than 90% were sensitive to gentamycin, levofloxacin and rifampicin.

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Microbial diversity of bioaerosol inside sports facilities and antibiotic resistance of isolated Staphylococcus spp.

Increasing bio-terror attacks across the world have alarmed the environmentalist and epidemiologist about the impacts of bioaerosols, especially on human health, ecosystems, and live stocks. Further, its fate has also been linked with future sustainability of rural and urban societies. These concerns have led the researchers to have in depth understanding of their sampling approaches, enumeration techniques, and survival factors. In this view, the suitable methods, available for the bioaerosol sampling i.e. filtration, impaction, and impingement are analyzed within the scope of the specific studies. With regard to compositional analysis of bioaerosols, detailed assessment revealed that overall microbial taxonomy cannot be expressed alone by culture-dependent methods, as majority of the microbial species are not culturable. Further, the overall diversity of the bioaerosols may be significantly expressed by means of culture-independent methods, in which various advanced sequencing techniques have resulted into wide range of outcomes in branch of genomics and metagenomics. In particular, the community structure is greatly influenced by the combination of various factors such as the complex interrelations between bacteria and fungi in form of co-occurrence or co-exclusion patterns, air pollution levels, and seasonal variations etc. The important meteorological parameters, responsible for their survival, transport, and contribution to the suspended particulate, include relative humidity, air temperature, wind direction, wind speed, rainfall, solar radiation. The correlation between these factors and bioaerosol concentration was observed to be either positive, negative, or non-significant as it is strongly governed by local weather conditions and seasonal changes of the investigated regions. Moreover, the complex inter-relationships between bioaerosols and environmental pollutants such as sulfur dioxide, carbon monoxide, and ozone also reported to influence the bioaerosol concentration. Overall, this review offers insight into the current state of bioaerosol sampling approaches, devised detection techniques, survival and transport factors, and associated health effects. Authors also encourage that future research should be pursued from a sustainability perspective with a vision of development of reliable sampling methods and detection techniques.

An opinion review on sampling strategies, enumeration techniques, and critical environmental factors for bioaerosols: An emerging sustainability indicator for society and cities

The present study is aimed at evaluating microbiological air pollution in libraries, cafeterias and selected classrooms of two schools in Bydgoszcz city, northern Poland and determining the antibiotic resistance of Staphylococcal strains isolated from the indoor air. One of the investigated schools (School A) is located in the very center of the city, in the vicinity of a park, among old houses and stone-lined streets, while the other (School B), among modern residential buildings, close to a street with heavy traffic. In each school, air samples were collected in the morning, always from all three sampling sites, using the MAS-100 sampler. Selective growth media were used for bacteria and mold isolation and quantifying analysis. The antibiotic resistance of the isolated mannitol-positive staphylococci was assessed using the disc diffusion method in accordance with EUCAST recommendations. The highest mean concentration of heterotrophic bacteria was recorded in the cafeterias: 884 CFU m−3 in School A and 1906 CFU m−3 in School B. Molds were the most abundant in the library and cafeteria in School B, where their average concentration exceeded 300 CFU m−3. Cladosporium and Penicillium species prevailed, while Fusarium, Acremonium and Aspergillus were less abundant. Airborne mannitol-positive staphylococci were recorded at low concentrations, ranging from 6 to 11 CFU m−3 on average. According to the taxonomic analysis, Staphylococcus aureus isolates were the most abundant in both schools, followed by S. xylosus, S. haemolyticus and S. saprophyticus. The antibiograms indicated that resistance to erythromycin was common in 62.5% of the isolated staphylococcal strains. Levofloxacin and gentamicin were the most effective antibiotics. No multidrug-resistant strains were identified.

https://www.mdpi.com/2073-4433/11/10/1105/pdf

Diversity of Bioaerosols in Selected Rooms of Two Schools and Antibiotic Resistance of Isolated Staphylococcal Strains (Bydgoszcz, Poland): A Case Study

Bioaerosol Sources, Sampling Methods, and Major Categories: A Comprehensive Overview

Bioaerosols are major air pollutants commonly found both indoors and outdoors. High exposure levels may result in various adverse health outcomes. Laboratories, which are indoor environments carefully designed for specific purposes, may contain high levels of bioaerosols, which may threaten worker’s health, and contaminate experimental results. This study investigated the levels of bioaerosols (i.e., culturable fungi and bacteria, and fungal spores) in laboratories in the Bangkok metropolitan area. Air samples were collected from 14 Class I and one Class II laboratories by using a single-stage impactor and a VersaTrap spore trap cassette. Colonies were counted after 72 h and 48 h of incubation for culturable fungi and bacteria, respectively. Culturable fungi and fungal spores were identified based on their morphological characteristics. Associations between bioaerosols and indoor air parameters and laboratory characteristics were evaluated. The concentrations (mean ± SD) of culturable bacteria, culturable fungi, and fungal spores were 87.0 ± 97.8 CFU/m3, 294.9 ± 376.1 CFU/m3, and 771.8 ± 545.3 spores/m3, respectively. Aspergillus/Penicillium, ascospores, and Cladosporium were common fungal spore taxa in the laboratories. Culturable fungi significantly increased with the number of staff and visible molds, whereas water leaks and culturable fungi significantly increased fungal spore concentrations. Culturable bacteria were positively associated with the numbers of trash bins and − 80 °C freezers. Although bioaerosol concentrations were considerably lower in the studied laboratories, proper indoor air management is still suggested in order to reduce emissions and exposure. This can help workers avoid adverse health outcomes and reduce the chance of experimental contamination.

Natkrita Kotchasatan

Papers

Bioaerosol levels and the indoor air quality of laboratories in Bangkok metropolis