Assessment of fungal bioaerosols and particulate matter characteristics in indoor and outdoor air of veterinary clinics

Urbanisation and Lockdown Impact on Airborne Fungal Communities in Tropical Landscapes: A Comparative Study of Urban and Peri-Urban Environments

This study assessed the concentration, composition, and spatiotemporal distribution of airborne fungi in a metropolitan area, comparing urban and peri-urban sites across rainy and dry seasons. An 8-month fungal bioaerosol monitoring was conducted using a six-stage Andersen cascade impactor. Data analysis involved generalised linear regression models and multifactorial ANOVA to assess the relationships between meteorological conditions, sampling sites, campaigns, fungal concentrations, and impactor stages. Additionally, a Bayesian neural network was developed to predict bioaerosol dynamics based on the analysed variables. We identified 10 viable fungal species, including Aspergillus niger, Aspergillus nidulans, Aspergillus. fumigatus, Aspergillus terreus, Aspergillus flavus, Aspergillus versicolor, Penicillium spp. and Fusarium oxysporum. Notable differences in the aerodynamic sizes of fungal particles influenced their distribution and potential impact on the respiratory system. The Bayesian neural network successfully predicted fungal bioaerosol concentrations with an accuracy of 76.87%. Our findings reveal the significant role of environmental and human-related factors in shaping bioaerosol distribution in tropical urban contexts. This research provides essential insights into the behaviour of fungal bioaerosols, highlighting their relevance for public health, especially for immunocompromised populations, and their impact on local agriculture. Furthermore, it demonstrates the potential of fungal bioaerosols as bioindicators for environmental monitoring and predictive modelling.

Diversity and Composition of the Airborne Fungal Community in Mexico City with a Metagenomic Approach

Airborne fungi are widely distributed in the environment and originate from various sources like soil, plants, decaying organic matter, and even indoor environments. Exposure to airborne fungal spores can cause allergic reactions, asthma, and respiratory infections. Certain fungi can cause serious infections, particularly in individuals with weakened immune systems. An aerobiological study was conducted to detect airborne fungi using metagenomics in three areas of Mexico City, each representing different degrees of urbanization, during the dry and rainy seasons of 2017. Seasonality showed a significant role in the composition of airborne fungi. Ascomycota predominated in the three areas sampled during dry and rainy seasons, with the genera Cladosporium and Penicillium presenting the highest relative abundances across seasons. The Agaromycetes showed an increase during the rainy season. Regarding the areas, the north and center sites showed similar meteorological conditions and fungal community composition patterns. According to the Shannon and Simpson indices, the south area showed a greater species diversity during the dry season. These insights into the interactions between urbanization, seasonality, and airborne microbial communities could contribute to more effective urban management, reduced health risks, and the promotion of sustainable development.

The abundance and pathogenicity of microbes in automobile air conditioning filters across the typical cities of China and Europe

Bioaerosols are widely distributed in urban air and can be transmitted across the atmosphere, biosphere, and anthroposphere, resulting in infectious diseases. Automobile air conditioning (AAC) filters can trap airborne microbes. In this study, AAC filters were used to investigate the abundance and pathogenicity of airborne microorganisms in typical Chinese and European cities. Culturable bacteria and fungi concentrations were determined using microbial culturing. High-throughput sequencing was employed to analyze microbial community structures. The levels of culturable bioaerosols in Chinese and European cities exhibited disparities (Analysis of Variance, P < 0.01). The most dominant pathogenic bacteria and fungi were similar in Chinese (Mycobacterium: 18.2-18.9 %; Cladosporium: 23.0-30.2 %) and European cities (Mycobacterium: 15.4-37.7 %; Cladosporium: 18.1-29.3 %). Bartonella, Bordetella, Alternaria, and Aspergillus were also widely identified. BugBase analysis showed that microbiomes in China exhibited higher abundances of mobile genetic elements (MGEs) and biofilm formation capacity than those in Europe, indicating higher health risks. Through co-occurrence network analysis, heavy metals such as zinc were found to correlate with microorganism abundance; most bacteria were inversely associated, while fungi exhibited greater tolerance, indicating that heavy metals affect the growth and reproduction of bioaerosol microorganisms. This study elucidates the influence of social and environmental factors on shaping microbial community structures, offering practical insights for preventing and controlling regional bioaerosol pollution.

Impact of cultivating different Ocimum species on bioaerosol bacterial communities and functional genome at an agricultural site

The effects of the surrounding environment on the bacterial composition of bioaerosol were well documented for polluted and contaminated sites. However, there is limited data on the impact of plant species, especially those that produce aromas, on bioaerosol composition at agricultural sites. Hence, the aim of this study is to evaluate the variability in bacterial communities present in bioaerosol samples collected from agricultural sites with aroma-producing crops. For this, PM2.5, PM10, and bioaerosol samples were collected from agricultural fields growing Ocimum [two varieties of O. sanctum (CIM-Aayu and CIM-Angana)] and O. kilimandscharicum (Kapoor), nearby traffic junctions and suburban areas. PM2.5 and PM10 concentrations at the agricultural site were in between the other two polluted sites. However, bioaerosol concentration was lower at agricultural sites than at other sites. The culturable bacteria Bacillus subtilis, Bacillus tequilensis, and Staphylococcus saprophyticus were more prevalent in agricultural sites than in other areas. However, the composition of non-culturable bacteria varied between sites and differed in three fields where Ocimum was cultivated. The CIM-Aayu cultivated area showed a high bacterial richness, lower Simpson and Shannon indices, and a distinctive metabolic profile. The sites CIM-Angana and CIM-Kapoor had a higher abundance of Aeromonas, while Pantoea and Pseudomonas were present at CIM-Aayu. Acinetobacter, Staphylococcus, and Bacillus were the dominant genera at the other two sites. Metabolic profiling showed that the CIM-Aayu site had a higher prevalence of pathways related to amino acid and carbohydrate metabolism and environmental information processing compared to other sites. The composition of bioaerosol among the three different Ocimum sites could be due to variations in the plant volatile and cross-feeding nature of bacterial isolates, which further needs to be explored.

Bioaerosol emissions from wastewater treatment process at urban environment and potential health impacts

The inlet of wastewater treatment plants (WWTPs) contains pathogenic microorganisms which during aeration and by mechanical mixing through wind typically aerosolized microbes into ambient air. Bioaerosol emission and its characterization (bacterial and fungal) was investigated considering low-flow and high-flow inlet of wastewater treatment plant. Generation of bioaerosols was found influenced by prevailing seasons while both during summer and winter, fungal concentration (winter: 1406 ± 517; summer: 1743 ± 271 CFU/m3) was higher compared to bacterial concentration (winter: 1077 ± 460; summer: 1415 ± 588 CFU/m3). Bioaerosols produced from WWTPs were predominately in the size range of 2.1-4.7 μm while fraction of fungal bioaerosols were also in ultra-fine range (0.65 μm). Bioaerosols reaching to the air from WWTPs varied seasonally and was calculated by aerosolization ratio. During summer, aerosolization of the bioaerosols was nearly 6 times higher than winter. To constitute potential health effects from the exposure to these bioaerosols, biological characterization, antibiotics resistance and the health survey of the nearby area were also performed. The biological characterization of the bioaerosols samples were done through metagenomic approach using 16s and ITS metagenomic sequencing. Presence of 167 genus of bacteria and 41 genus of fungi has been found. Out of this, bacillus (73%), curtobacterium (21%), pseudomonas, Exiguo bacterium, Acinetobacter bacillaceae, Enterobacteriaceae and Prevotella were the dominant genus (top 10) of bacteria. In case of fungi, xylariales (49%), Hypocreales (19%), Coperinopsis (9%), Alternaria (8%), Fusarium (6%), Biopolaris, Epicoccum, Pleosporaceae, Cladosporium and Nectriaceae were dominant. Antibiotics like, Azithromycin and cefixime were tested on the most dominant bacillus showed resistance on higher concentration of cefixime and lower concentration of azithromycin. Population-based health survey in WWTP nearby areas (50-150 m periphery) found several types of diseases/symptoms including respiratory problem, skin rash/irritation, change in smell and taste, eye irritation within the resident population and workers.

Moss-bag technique as an approach to monitor elemental concentration indoors

The moss-bag technique has been used for many decades to monitor outdoor pollution. More recently, however, the method has been used to monitor indoor air pollution (IAP), as humans spend the majority of their time indoors. The purpose of the research conducted was to evaluate indoor air pollution using active moss biomonitoring. Pleurozium schreberi moss bags were exposed for two seasons (summer and winter), hanging over tile stoves and coal stoves. The selected elements: Al, Cu, Cd, Co, Pb, Zn, V, Ba, Cr, Fe, Mn, Sr, P, Ni, and S were determined by Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) and, for Hg, by a direct mercury analyzer. The study found the exposure season affected the concentrations of selected elements in 62.5% of cases, and their source was identified. The average concentrations of Co, Ba, Cr, and Sr were higher, and statistically significant, in winter, after a 12-week exposure period of the mosses, regardless of the type of heating or cooking stove owned. The higher phosphorus concentrations obtained in summer indicate physiological stress caused by unfavorable winter exposure conditions. In the future, the number of species used to assess indoor air pollution should be increased and the range of pollutants expanded, along with the identification of their sources, taking residents' lifestyles into account.

Microbiological Indoor and Outdoor Air Quality in Chicken Fattening Houses

This study was conducted at one of the largest poultry companies in Kuwait during November and December 2019 to evaluate the microbiological threats of Escherichia coli (APEC), Salmonella spp., and Aspergillus fumigatus to chickens in fattening houses by counting and identifying the microorganisms by culturing and pyrosequencing analysis. During the fattening cycle, the temperature and humidity ranged between 23.6°C and 29°C and 64.1% and 87.1%, respectively. The total bacterial population and Aspergillus fumigatus measured in the indoor and outdoor air exhibited a linear relationship during the fattening cycle. The total bacterial and Aspergillus concentrations determined during the cycle ranged between 150 and 2000 CFU/m³ and 0 and 1000 CFU/m³, respectively. E. coli and Salmonella spp. concentrations determined during the cycle ranged between 1 and 220 CFU/m³ and 4 and 110 CFU/m³, respectively. Pyrosequencing analysis of the air inside the houses at the end of the cycle revealed extensive biodiversity in the microorganisms, detecting 32 bacterial genera and 14 species. The identified species belonging to the genera Corynebacterium, Haemophilus, Streptococcus, Veillonella, and Aspergillus were identified as potentially affecting human and broiler health. The emission of potentially pathogenic bacteria to the outdoor environment from chicken housing can pose a considerable risk to human health and environmental microbial pollution. This study could guide the development of integrated control devices for monitoring microbes in broiler production facilities during chicken collection for transport to slaughterhouses.

Characteristics and health effects of particulate matter emitted from a waste sorting plant

Solid waste components can be recycled in waste paper and cardboard sorting plants (WPCSP) through a multistep process. This work collected 15 samples every six days from each of the 9 points selected to study the processes taking place in a WPCSP (135 particulate matter samples total). Examining the concentration and size fraction of particulate matter (i.e., PM₁, PM_2.5 and PM₁₀) in WPCSP is an essential issue to notify policy makers about the health impacts on exposed workers. The major activities for increasing of the concentration of PM in various processing units in the WPCSP, especially in hand-picking routes I and II were related to manual dismantling, mechanical grinding, mechanical agitation, and separation and movement of waste. The results of this work showed that a negative correlation between temperature and particulate matter size followed the order PM₁₀ > PM_2.5 > PM₁. Exposure to PM_2.5 and PM₁₀ in the WPCSP lead to possible risk (HI = 5.561 and LTCRs = 3.41 × 10^-6 to 9.43 × 10^-5 for PM_2.5 and HI = 7.454 for PM₁₀). The exposure duration and the previous concentrations had the most effect on the ILCRs and HQs for PM_2.5 and PM₁₀ in all sampling sites. Hence, because WPCSP are infected indoor environments (I/O ratio > 1), the use of control methods such as isolation of units, misting systems, blower systems equipped with bag houses, protective equipment, a mechanical ventilation system, and additional natural ventilation can reduce the amount of suspended PM, enhance worker safety, and increase the recycling rate.

Characteristics and assessing biological risks of airborne bacteria in waste sorting plant

Examining the concentration and types of airborne bacteria in waste paper and cardboard sorting plants (WPCSP) is an urgent matter to inform policy makers about the health impacts on exposed workers. Herein, we collected 20 samples at 9 points of a WPCSP every 6 winter days, and found that the most abundant airborne bacteria were positively and negatively correlated to relative humidity and temperature, respectively. The most abundant airborne bacteria (in units of CFU m^-3) were: Staphylococcus sp. (72.4) > Micrococcus sp. (52.2) > Bacillus sp. (30.3) > Enterococcus sp. (24.0) > Serratia marcescens (20.1) > E. coli (19.1) > Pseudomonas sp. (16.0) > Nocardia sp. (1.9). The lifetime average daily dose (LADD) for the inhalation and dermal routes for the intake of airborne bacteria ranged from 3.7 × 10^-3 ≤ LADD_Inhalation ≤ 2.07 × 10¹ CFU (kg d)^-1 and 4.75 × 10^-6 ≤ LADD_Dermal ≤ 1.64 × 10^-5 CFU (kg d)^-1, respectively. Based on a sensitivity analysis (SA), the concentration of airborne bacteria (C) and the exposure duration (ED) had the most effect on the LADD_Inhalation and LADD_Dermal for all sampling locations. Although the Hazard Quotient of airborne bacteria was HQ < 1, an acceptable level, the indoor/outdoor ratio (1.5 ≤ I/O ≤ 6.6) of airborne bacteria typically exceeded the threshold value (I/O > 2), indicating worker's exposure to an infected environment. Therefore, in the absence of sufficient natural ventilation the indoor ambient conditions of the WPCSP studied should be controlled by supplying mechanical ventilation.