Characteristics of Surface Ozone Levels at Climatologically and Topographically Distinct Metropolitan Cities in India

• Published in: Asian journal of atmospheric environment (Online) Vol. 16; no. 2; pp. 1 - 20
• Main Authors: Kutal, Ganesh, Kolhe, Amol, Mahajan, Chandrashekhar, Varpe, Sandeep, Patil, Rupesh, Singh, Prayagraj, Aher, Gajanan R
• Format: Journal Article
• Language: English
• Published: Singapore Springer Nature Singapore 01.06.2022; Springer; 한국대기환경학회
• Subjects: Anthropogenic emissions; Atmospheric Sciences; Earth Sciences; Meteorology; Ozone precursor’s; Photochemical reactions; Research Article; Surface ozone; Temporal variation; 대기과학; Anthropogenic emissions; Temporal variation; Photochemical reactions; Ozone precursor’s; Surface ozone
• ISSN: 2287-1160; 1976-6912; 2287-1160
• DOI: 10.5572/ajae.2022.004

Surface ozone (O 3 ) data at Pune (1998–2014) and Delhi (1998–2013) are studied to examine their temporal characteristics. Study also examines role of meteorology and atmospheric boundary layer height (ABLH) in modulating surface O 3 at these sites. Using diurnal variability of surface O 3 , rate of change of surface O 3 , [d(O 3 )/dt] is estimated to infer the nature of surface O 3 formation/destruction mechanisms. Analysis of data reveals that at both locations, surface O 3 concentrations during daytime are significantly high as compared to those during nighttime. Seasonally, at Pune averaged daytime surface O 3 concentrations are high during pre-monsoon and low in monsoon while those during winter and post-monsoon are found to be significantly higher than those in monsoon but half as compared to those in pre-monsoon. At Delhi, averaged daytime surface O 3 concentration is minimum in winter and maximum in pre-monsoon with monsoon and post-monsoon values being about 0.79–0.82 times with respect to pre-monsoon O 3 concentrations. High natural/anthropogenic pollutant concentration, abundance of ozone precursor gases, high temperature and high rate of photo-oxidation of precursor gases due to solar flux are the causal factors for increased surface O 3 concentrations in pre-monsoon season. Reduced solar flux decreases photo-dissociation of ozone precursor gases resulting in low O 3 concentration during winter season. Occurrence of low surface O 3 during early morning hours in monsoon, post-monsoon and winter seasons is because of low ABLH and low stratosphere-troposphere exchange (STE). [d(O 3 )/dt] values during morning/evening at Pune and Delhi are indicative of asymmetric and symmetric nature of ozone formation/destruction mechanisms.