Fungal spore air pollution in selected environments in Nairobi, Kenya

Abstract

ABSTRACT Fungal spores constitute major bioaerosols and are important indicators of bio-pollution. The rural–urban migration has increased human activity, causing air pollution concerns globally. This study explored the seasonal load, distribution, and diversity of fungal spores at different strategic sites in Nairobi, Kenya. The fungal air spores were systematically collected from markets, roads, and recreational, and dumping sites within Nairobi City County. Briefly, Sabouraud Dextrose Agar (SDA) plates were exposed on site for 5 minutes, and transported for incubation at 28°C for 7 days. Temperature, humidity, and wind speed data were recorded using the AccuWeather mobile app. Fungal cultures were identified using standard macro and micro-phenotypic features. The relationship between the fungal concentration and meteorological parameters was analyzed using multiple regression and PNiger. The wet season had the highest number of fungal spores (5318.88 CFU m− 3) compared to the dry season (1929.58 CFU m− 3.) We identified 502 isolates across two seasons; 16 genera and 38 species comprising Ascomycota 426 (89.31%), Basidiomycota 21 (4.40%), Deuteromycota 17 (3.56%), Muromycota 7(1.47%) and Zycomycota 6(1.26%). The most isolated fungal genera included Candida (17.13%), followed by Penicillium 66 (13.15%), Fusarium 62 (12.35%), Aspergillus 61 (12.15%) and Cladosporium 60 (11.95%). Temperature, humidity and windspeed significantly affected airborne fungal concentration (p = .000), (p = .0280) and (p = .000), respectively. Pearson correlation analysis showed that the temperature negatively correlated with the fungal concentration significantly (p = .000), humidity positively correlated with the fungal concentration significantly (p = .001), and wind speed negatively correlated with the fungal concentration significantly (p = .000). Our findings highlight the significance of fungal air pollution and the possible risks of human mycoses. The significance of fungal spore pollutants and human mycoses to climate change needs to be explored.