An opinion review on sampling strategies, enumeration techniques, and critical environmental factors for bioaerosols: An emerging sustainability indicator for society and cities

Abstract

Increasing bio-terror attacks across the world have alarmed the environmentalist and epidemiologist about the impacts of bioaerosols, especially on human health, ecosystems, and live stocks. Further, its fate has also been linked with future sustainability of rural and urban societies. These concerns have led the researchers to have in depth understanding of their sampling approaches, enumeration techniques, and survival factors. In this view, the suitable methods, available for the bioaerosol sampling i.e. filtration, impaction, and impingement are analyzed within the scope of the specific studies. With regard to compositional analysis of bioaerosols, detailed assessment revealed that overall microbial taxonomy cannot be expressed alone by culture-dependent methods, as majority of the microbial species are not culturable. Further, the overall diversity of the bioaerosols may be significantly expressed by means of culture-independent methods, in which various advanced sequencing techniques have resulted into wide range of outcomes in branch of genomics and metagenomics. In particular, the community structure is greatly influenced by the combination of various factors such as the complex interrelations between bacteria and fungi in form of co-occurrence or co-exclusion patterns, air pollution levels, and seasonal variations etc. The important meteorological parameters, responsible for their survival, transport, and contribution to the suspended particulate, include relative humidity, air temperature, wind direction, wind speed, rainfall, solar radiation. The correlation between these factors and bioaerosol concentration was observed to be either positive, negative, or non-significant as it is strongly governed by local weather conditions and seasonal changes of the investigated regions. Moreover, the complex inter-relationships between bioaerosols and environmental pollutants such as sulfur dioxide, carbon monoxide, and ozone also reported to influence the bioaerosol concentration. Overall, this review offers insight into the current state of bioaerosol sampling approaches, devised detection techniques, survival and transport factors, and associated health effects. Authors also encourage that future research should be pursued from a sustainability perspective with a vision of development of reliable sampling methods and detection techniques. • Fate of bioaerosols is directly linked with sustainable development of societies. • Interaction of ambient bioaerosols and other co-pollutants is discussed. • Enumeration techniques of bioaerosols are critically analyzed. • Influence of meteorology on survival and dispersion of bioaerosols is investigated.