Indoor air pollution due to bacterial bioaerosols in beauty salons of Ardabil, Iran: characterization, influencing factors and health risk assessment

Beauty salons are establishments that provide hair, face, and body treatments for consumers. In this research, type of bacteriological pollution and the associated bacteriological human health risks were evaluated using Monte Carlo Simulation. A cross-sectional study design was carried out in 50 randomly selected beauty salons in Ardabil, during April-June, 2022. Pseudomonas (74 ± 42 CFU/m³) was found frequently in almost all (98%) of the salons. Staphylococcus (9 ± 25 CFU/m³) and Escherichia coli (5 ± 13 CFU/m³) were found in 20%, and Acinetobacter (2 ± 7 CFU/m³) was found in 10% of the salons. Salons with makeup and hair dressing had higher concentrations of Staphylococcus. The concentrations of bacteria fairly decreased with relative humidity and increased with the temperature. Furthermore, higher concentrations of the bioaerosols were observed in larger salons and more crowded salons. There was no significant correlation between the type of heating system, building material of the walls, type of ventilation system, as well as bride’s makeup in the salons with concentration of the bioaerosols. The average annual infection risk of Escherichia coli 7.27 (10^− 4) per person per year (pppy), which was higher than the acceptable limit (10^–4 pppy) suggested by WHO. The results of health risk were above the safe limit of EPA and WHO, indicating possible adverse effects to exposed individuals.