Indices used for assessment of air quality.

Abstract

Abstract Copious evidence suggests that rapid urbanization and widespread anthropogenic activities are the main factors resulting in high levels of ambient air pollutant over the Indo-Gangetic Plain (IGP) in India. Continuous monitoring of levels of air pollutants affecting air quality, human health and the ecosystem is essentially required on a day-to-day basis. The influence of pollutants on the air quality, human health and susceptibility of plants is studied widely with the help of various indices, e.g. air-quality index (AQI), air-quality health index (AQHI), air-pollution index (API), air-pollution tolerance index (APTI) and anticipated performance index. In this chapter, we discuss the important indices: AQI, AQHI, API and APTI. As a case study, we have discussed in detail the AQI. We report on the status of ambient air quality (for the year 2016) over the IGP, utilizing the CPCB (Central Pollution Control Board, India) database. Air quality index (AQI) values have been presented systematically in this chapter to better evaluate the air quality associated with various major and potential atmospheric pollutants (available in CPCB database). Ambient data of air pollutants (PM2.5 or PM10, SO2, NO, NO2 and CO) have been retrieved from three sites continuously monitored by CPCB: upwind (Panchkula; states of Haryana), central (Lucknow; states of Uttar Pradesh) and downwind locations (Kolkata; West Bengal) in the IGP. Monthly and seasonally averaged data sets have been discussed and compared for the aforementioned three sites. Results suggest that Lucknow (in central IGP) was more polluted than the Kolkata and Panchkula sites (upwind of major polluting sources in the IGP). Relative to Lucknow, low concentrations of air pollutants at Kolkata suggests the influence of sea- and land-breeze wind systems on ventilation coefficient and efficient dispersion of the pollutants. AQI values at Kolkata ranging between 27 and 137 indicate a good to moderately polluted atmospheric scenario. However, AQI at Lucknow ranging between 301 and 400 indicates very poor air quality, particularly during post-monsoon and wintertime, whereas at Panchkula during most of the time, air quality was found to be satisfactory (AQI: 51-100). The present synthesis documents the air quality scenario over the IGP in a versatile and simplified manner that can be also be utilized for public awareness.