Chapter 11 - Air quality and its impact on urban environment

Abstract

Air quality (AQ) is defined by particles and gaseous components present in the ambient atmosphere. The wide range of particles (with an aerodynamic diameter ranging from 0.1nm to 100μm) present in the atmosphere is considered as suspended particulate matter (SPM). Further, particles with aerodynamic diameter ≤2.5μm and ≤10μm are termed as PM2.5 and PM10, respectively. These particles are a major concern for human health, climate change, nutrient dynamics and atmospheric chemistry. In addition, the gaseous pollutants (O3, SOx, NOx, CO) and Pb also affect the human health, plants and animals predominantly in the urban environment. The air quality of the megacities across India as well as around the world is deteriorating day by day, which can be attributed to the increasing vehicular and industrial emission, resuspension of road dust along with biomass and coal burning. With the unplanned development of the buildings, industries in megacity restrict the dispersion and self-cleaning capacity of the atmosphere. The mass concentration and chemistry of air pollutant are influenced by sources, their strength, meteorological factors (wind speed, wind direction, humidity and mixing height) and geographical location of the urban environment. This chapter highlights the emission flux of multiple pollutants, their effect and sustainable growth of urban areas without compromising the air quality. In addition, the temporal evolution, interannual variability and seasonal spatial distribution of few natural and anthropogenic aerosols are also discussed with special reference to Delhi.