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Analysis of Diurnal and Seasonal Behavior of Surface Ozone and Its Precursors (NOx) at a Semi-Arid Rural Site in Southern India

Category: Articles

Volume: 12 | Issue: 6 | Pages: 1081-1094
DOI: 10.4209/aaqr.2012.03.0055

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B. Suresh Kumar Reddy1,3, K. Raghavendra Kumar1,4, G. Balakrishnaiah2, K. Rama Gopal 1, R.R. Reddy1, V. Sivakumar4, A.P. Lingaswamy1, S.Md. Arafath1, K. Umadevi1, S. Pavan Kumari1, Y. Nazeer Ahammed5, Shyam Lal6

  • 1 Aerosol & Atmospheric Research Laboratory, Department of Physics, Sri Krishnadevaraya University, Anantapur 515 055, Andhra Pradesh, India
  • 2 Institute of Environmental Engineering, National Chiao Tung University, No. 1001 University Road, Hsinchu, 300, Taiwan
  • 3 Institute of Low Temperature Science, Hokkaido University, Sapporo 060 0819, Japan
  • 4 School of Chemistry and Physics, University of KwaZulu-Natal, Westville Campus, Durban 4000, South Africa
  • 5 Atmospheric Science Laboratory, Department of Physics, Yogi Vemana University, Kadapa 516 003, Andhra Pradesh, India
  • 6 Space and Atmospheric Sciences Division, Physical Research Laboratory, Ahmedabad 380 009, Gujarat, India


Surface measurements of O3, NO, NO2 and NOx have been made over a semi-arid rural site, Anantapur (14.62°N; 77.65°E; 331 m asl) in southern India, during January-December 2010. The highest monthly mean O3 concentration was observed in April (56.1 ± 9.9 ppbv) and the lowest in August (28.5 ± 7.4), with an annual mean of 40.7 ± 8.7 ppbv for the observation period. Seasonal variations in O3 concentrations were the highest during the summer (70.2 ± 6.9 ppbv), and lowest during the monsoon season (20.0 ± 4.7 ppbv), with an annual mean of 40.7 ± 8.7 ppbv. In contrast, higher NOx values appeared in the winter (12.8 ± 0.8 ppbv) followed by the summer season (10.9 ± 0.7 ppbv), while lower values appeared in the monsoon season (3.7 ± 0.5 ppbv). The results for O3, NO and NO2 indicate that the level of oxidant concentration ([OX] = NO2 + O3) at a given location is the sum of NOx-independent “regional contribution” (background level of O3) and linearly NOx-dependent “local contribution”. The O3 concentration shows a significant positive correlation with temperature, and a negative correlation with both wind speed and relative humidity. In contrast, NOx have a significant positive correlation with humidity and wind speed, and negative correlation with temperature. The slope between [BC] and [O3] suggests that every 1 μg/m3 increase in black carbon aerosol mass concentration causes a reduction of 4.7 μg/m3 in the surface ozone concentration. A comparative study using satellite data shows that annual mean values of tropospheric ozone contributes 12% of total ozone, while near surface ozone contributes 82% of tropospheric ozone. The monthly mean variation of tropospheric ozone is similar to that tropospheric NO2, with a correlation coefficient of +0.80.


Surface ozone Nitrogen dioxide NOx Oxidant Tropospheric ozone

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