Photochemical Smog in Delhi: Impact, Analysis and Future trends

Abstract

Smog is the haze that envelopes the ambient atmosphere of urban cities. It is generated due to chemical reaction between   Nitrogen Oxides (NO_X) and volatile organic compounds(VOC) catalyzed by solar UV radiation which leads to formation of ground level Ozone and PAN (Peroxyacyl Nitrate) as the main products of smog. In recent years Delhi has been facing very frequent episodes of this visible type of air pollution. This brought us to study the Smog formation in Delhi.

In this work, data is collected for the period of seven years, from 2016 to 2022 from Central Pollution Control Board (CPCB, GOI) website.  We have used correlation and linear regression analysis along with descriptive analysis to analyse and predict  the trend of smog generating pollutants i.e., volatile organic compound (VOC), Nitrogen Oxides (NO and NO₂), Ground level ozone(O₃), suspended particulate matter and respirable suspended particulate matter (PM10 and PM 2.5), and certain environmental factors like wind direction and speed, relative humidity and atmospheric temperature. The formation of smog shows seasonal variability and also the weather characteristics influence smog formation along with anthropogenic reasons. Smog formation has deleterious health effects. In pandemic times the spell of fog decreased appreciably indicating that smog is controllable by human interventions.   Smog not only causes severe health disorders but ozone is detrimental for vegetation too.