Seasonal variation and size distribution in the airborne indoor microbial concentration of residential houses in Delhi and its impact on health

Abstract

Exposure of microbial agents in the air of indoor dwellings is associated with effects on respiratory and general health. The current study was conducted in the urban area of Delhi Metropolis for the seasonal quantitative assessment of viable microbial indoor air quality. Bioaerosol measurement was conducted by using Anderson six stage impactor with cut-off diameters of 7.0, 4.7, 3.3, 2.1, 1.1, and 0.65 µm) throughout the all the seasons (April 2019 to March 2020). Meteorological parameters such as temperature and relative humidity were measured to check their effect on microbial survival. Air quality index data of the sampling area were recorded by DPCC air quality monitoring system, Ashok Vihar, Delhi. The highest (1654 ± 876.87 CFU/m 3 ) and lowest (738 ± 443.59 CFU/m 3 ) mean bacterial concentration in houses was recorded in August and December, respectively. Similarly, the highest fungal concentration (1275 ± 645.22 CFU/m 3 ) was found in August and the lowest in (776 ± 462.46 CFU/m 3 ) in January. Bacterial respirable fraction shows an irregular pattern in different seasons. In the case of fungi, the respirable fraction of 2.1 and 1.1 contributes more than 60% of total culturable bioaerosols in all seasons. Bacterial genera including Staphylococcus, Micrococcus, and Streptobacillus were most dominant, and Cladosporium , Aspergillus , Penicillium , and Alternaria were the most dominant fungal genera observed indoors. The results of this study suggest that higher respirable fungal fraction might penetrate deeper into the lungs and cause various health effects. A higher concentration of bioaerosols in outdoor areas than indoor shows that the source of indoor bioaerosols is outdoor air. Supplementary Information The online version contains supplementary material available at 10.1007/s10453-021-09718-3.

Comprehensive health risk assessment of microbial indoor air quality in microenvironments

“…Staphylococcus, Micrococcus, and Streptococcus were the most dominant bacterial genera in indoor than outdoors in the current study and previous studies [28,31,35]. A high abundance of Cladosporium in indoors indicate that outdoor conditions significantly affect the indoor fungal concentration.…”

“…Few studies have been conducted in Delhi to measure biological pollution at various locations, with the majority of the studies focusing on educational institutes, libraries, dumping sites, and so on [27,28,37,[44][45][46]. In addition, the houses of patients suffering from asthma/ allergies reported (110,091) and (107,070) fungal colonies per cubic meter area in indoor and outdoor areas, respectively reported by [47].…”

“…Delhi, India's national capital, is the country's most polluted city, drawing increased attention from the government and the general public. A few studies have been conducted in Delhi to assess the total bacterial and fungal concentration in residential areas and waste dumping sites [25][26][27][28] However, previous studies could not indicate the possible association between indoor air quality and health issues in different seasons.…”

Seasonal variation of airborne fungal diversity and community structure in urban outdoor environments in Tianjin, China

“…In a study conducted on infants with asthma, Gent et al (2002) reported that the higher Penicillium concentrations were linked to a higher likelihood of wheezing and chronic cough. Seasonal changes in the environment are known to determine important variations in outdoor airborne fungal communities (Larsen, 1981;Kumar et al, 2021;Núñez et al, 2021;Yuan et al, 2022). We found a significant difference in fungal concentration in the analyzed environments in Tianjin, with the highest level recorded in spring and the lowest in winter.…”

Characterization of size segregated fungal bioaerosols in and around a Sugar Mill of Western Uttar Pradesh, India

“…The concentration and exposure duration may cause a serious range of allergic diseases related to the skin, eyes, ears, gastrointestinal tract and respiratory system (Faridi et al, 2016;Sandeep et al, 2020). Such incidences are more prominent in industrial areas than residential and commercial areas (Kumar et al,2021). For instance, the inhalation of industrial and agricultural specks of dust is considered as the principal cause of respiratory allergy in occupational areas (Dutkiewicz, 2011).…”