Seasonal variation of the surface ozone and its precursor gases during 2001–2003, measured at Anantapur (14.62°N), a semi-arid site in India

• Published in: Atmospheric research 2006-01, Vol.80 (2), p.151-164
• Main Authors: Ahammed, Y. Nazeer, Reddy, R.R., Gopal, K. Rama, Narasimhulu, K., Basha, D. Baba, Reddy, L. Siva Sankara, Rao, T.V.R.
• Format: Article
• Language: English
• Subjects: Anthropogenic emissions; Applied sciences; Atmospheric pollution; Chemical composition and interactions. Ionic interactions and processes; Earth, ocean, space; Exact sciences and technology; External geophysics; Meteorology; Ozone production rate; Pollutants physicochemistry study: properties, effects, reactions, transport and distribution; Pollution; Precursor gases; Regional photochemical pollution; Semi-arid zone; Surface ozone; Tropics
• ISSN: 0169-8095; 1873-2895
• DOI: 10.1016/j.atmosres.2005.07.002

A systematic analysis of surface ozone and its precursor gases observed in a semi-arid region centered at Anantapur is presented. The analysis is based on ozone and its precursor gas (NO x and CO) data for the rural station Anantapur, which is about 200 and 400 km from the two nearby major cities, Bangalore to the south and Hyderabad to the north, respectively. Ozone levels were highest during the winter and summer period and lowest during the monsoon. The rate of increase in O 3 is greatest (about 4.7 ppbv/h) around 0900 h local time, whereas the magnitude of the maximum rate of decrease during the evening is considerably smaller (about − 3.0 ppbv/h). This feature distinguishes the urban and rural sites since the magnitudes of the rates during morning and evening are more similar at urban sites. A high annual average ozone mixing ratio is observed at Anantapur (35.9 ppbv) in comparison with Gadanki (25 ppbv), Pune (16 ppbv), Ahmedabad (13 ppbv) and Delhi (11 ppbv). At Anantapur, annual averages of oxides of nitrogen (NO x ) and CO are observed as 3.9 ± 0.6 ppbv and 436 ± 64 ppbv, respectively.