Pathogenicity, Characterisation and Impact of Ambient Bio-Aerosols on the Climatic Processes: With a Special Emphasis on the Indian Subcontinent

Airborne particulate matter contains biological entities from various anthropogenic/biogenic activities. Within 1 nm–100 μm size, these are carried to long distances through various external agents. Identified as potential pathogens, they bring forth substantial economic losses in many parts of the world. Despite these shortcomings, bio-aerosols play a vital role in cloud condensation, ice nucleation, precipitation and various atmospheric processes affecting the hydrological cycle in general. Furthermore, bio-aerosols play a decisive role in the dispersal of reproductive plant parts and fungal spores, which play important roles in the evolution and sustenance of ecosystems. However, there remains substantial knowledge on air micro-biome with respect to their occurrence, transformation, role in climate change, interaction and impact on living organisms, agriculture and ecosystem. The current COVID-19 pandemic is a wakeup call for retrospective analysis of airborne particles to reduce their emission, transmission and health risk hazards while understanding their impact on various atmospheric processes. This chapter identifies the various types of bio-aerosols and systematically includes their prime role in the climatic processes, pathogenicity to the exposed flora and fauna along with an exclusive interrogation into their types and characterisation over the Indian subcontinent with a hugely diverging population and pollution panorama.