Emissions of Bioaerosols from Composting Facilities

Composting is a waste management procedure leading to the degradation of organic substances into stable end-products that can be used as fertilizer. However, one of the major public health concerns is the emissions of bioaerosols from the composting sites. Bioaerosol dispersion across composting facilities, due to operational activities, may have significant effects on human health due to the fact that they can penetrate into the human respiratory system leading to various toxic, allergenic and infectious diseases. Therefore, in this study emissions of bioaerosols from composting sites were characterized utilizing molecular techniques in order to investigate the microbial diversity and the extent of dispersal across facilities. Bioaerosols emissions were evaluated during different seasons at a UK composting site and for the warm season at two sites in Lahore (Pakistan) to assess the impact of seasonal meteorological factors on the composition and abundance of bioaerosols. Maximum abundance was found onsite with the minimum upwind. Maximum abundances of total bacteria (5.52 x 10¹º copies/m³) and Saccharopolyspora rectivirgula (8.7 x 10 8 copies/m³) obtained during summer suggested a positive influence of temperature on microbial abundances. Minimum abundance of bioaerosols was obtained during the winter season. Further, microbial community composition analysis indicated differences in the bacterial and fungal populations between the compost and bioaerosols obtained from different locations of the composting sites. Emissions of bioaerosols were also investigated in laboratory scale composting experiments at different temperatures and moisture levels to gain further insights into the impact of atmospheric factors on the fate of bioaerosols. Higher temperatures led to the increased abundances of total bacteria and Aspergillus fumigatus but had a negative effect on the abundance of Saccharopolyspora rectivirgula . The findings of the study have indicated that seasonal variations along with other parameters impact on the dispersion and diversity of bioaerosols which is an important consideration in the re-evaluation of the risk assessment policy regarding composting facilities.