Analyzing airborne fungal concentration in Kolkata, India: temporal distribution, the effect of atmospheric parameters and health impact

Airborne fungal spores constitute a significant fraction of atmospheric bioparticles, and most of them are responsible for causing the respiratory allergy. The present study deals with the evaluation of fungal aerospora by microscopy-based and culture-based methods in one outdoor and six indoor microenvironments in Kolkata, India, from May 2014 to April 2017. The association of environmental parameters with spore concentrations was explored by Spearman’s rank correlation analysis and multiple regression analysis. The impact of spore concentrations on the local population was assessed through a questionnaire survey, linear regression analysis, and Skin Prick Test (SPT). The maximum spore concentration was found in the outdoor environment. Ascospores, Cladosporium spp., Aspergillus/Penicillium spp., and basidiospores were found as major taxa recorded by microscopy-based method, whereas in culture-based method, Aspergillus spp. were abundant. In the outdoor, particles with aerodynamic diameter < 10 µm (PM₁₀) and in indoors, temperature, relative humidity, wind speed, average sun hour, PM₁₀, and ambient nitrogen dioxide concentration (NO₂) were identified as significant predictors. The linear regression analysis showed several positive associations of major taxa with respiratory diseases in the local inhabitant. SPT with several fungi was able to induce allergic inflammation in a selected atopic patient cohort. Analysis of spore concentrations and their relation with environmental parameters will give an insight into the air quality in Kolkata. The association with respiratory diseases will shed a light on the increasing burden of airway diseases in the urban megacity. Observations from this study will be useful for assessing the potential health impact on residents.