Characterization of bioaerosols in Northeast India in terms of culturable biological entities along with inhalable, thoracic and alveolar particles

Effort was made to analyse the biological components along with inhalable, thoracic and alveolic particles in aerosol samples collected from nine distinct locations of Northeast India during post-monsoon season (October–November) for the very first time. Microscopic analysis reveals the presence of 70–90% of non-biological particles followed respectively by pollens (9–18%), animal debris (1–12%) and fungal spores (1–6%). The concentration of bacteria in air sample ranges from 45.5 to 645.84 CFU/m3. All the bacterial isolates showed sensitivity against broad (Chloramphenicol and Ampicillin) and narrow (Vancomycin and Erythromycin) spectrum antibiotics which indicates lesser threat to human health. Moreover, the concentration of microbial content in the bioaerosol samples are less compared to some of the reported values in other parts of India. The predominant microbial genera in the collected bioaerosol samples were identified as Gram positive Diplobacilli sp. followed by Diplococci sp. Pollens of 10–20 µm diameter, which are mostly considered as potential allergens, contribute only up to 20% of total pollen content in the bioaerosol sample collected from various locations indicating healthier air.