Health Risk Assessment of Variable Airborne Bacterial Occurrences at Different Occupational Sites in Davangere City, India

Bioaerosols are associated with widespread health challenges. Many ubiquitous bacteria in the form of bioaerosols are known to be etiological factors in human diseases. This study evaluated the qualitative and quantitative prevalence of indoor and outdoor airborne microbial loads at four different occupational sites in Davanagere city, Karnataka, India, between 2021 and 2023. Various traditional isolation methods and media, including soybean casein digest agar and HiCrome agars, were used in this study. Seasonal variations significantly influenced bacterial loads, with Staphylococcus spp. emerging as the dominant species, particularly in school zones and garden areas. Hospital OTs exhibited fluctuating microbial loads, with Escherichia spp. decreasing significantly, whereas Staphylococcus spp. showed an overall increase. The market and garden sites followed similar trends, with Proteus spp. and Klebsiella spp. decreasing. Hierarchical clustering revealed distinct seasonal patterns, with bacterial proliferation peaking in March–May. Disinfectant efficacy tests revealed that both Savlon and Dettol effectively inhibited most pathogens, with E. coli and P. aeruginosa requiring longer exposure times. These findings highlight the impact of seasonal factors and disinfection strategies on bacterial distribution. In conclusion, seasonal and geographic factors influence microbial distributions, highlighting the importance of monitoring bioaerosols to mitigate bacterial diseases and other associated risks, especially in urban settings.