ORIGINAL PAPER Surface ozone concentrations in Agra: links with the prevailing meteorological parameters Vyoma Singla & Tripti Pachauri & Aparna Satsangi & K. Maharaj Kumari & Anita Lakhani Received: 26 April 2011 / Accepted: 8 March 2012 / Published online: 30 March 2012 # Springer-Verlag 2012 Abstract Measurements of surface ozone (O 3 ), nitric oxide (NO), nitrogen dioxide (NO 2 ), oxides of nitrogen (NO x =NO+NO 2 ) and meteorological parameters have been made at Agra (North Central India, 27°10’ N, 78°05’E) in post monsoon and winter season. The diur- nal variation in O 3 concentration shows daytime in situ pho- tochemical production with diurnal maximum in noon hours ranging from 51 to 54 ppb in post monsoon and from 76 to 82 ppb in winter, while minimum (16–24 ppb) during nighttime and early morning hours. Average 8-h O 3 concentration varied from 12.4 to 83.9 ppb. The relationship between meteorolog- ical parameters (solar radiation intensity, temperature, relative humidity, wind speed and wind direction) and surface O 3 variability was studied using principal component analysis (PCA), multiple linear regression (MLR) and correlation anal- ysis (CA). PCA and MLR of daily mean O 3 concentrations on meteorological parameters explain up to 80 % of day to day ozone variability. Correlation with meteorology is strongly emphasized on days having strong solar radiation intensity and longer sunshine time. 1 Introduction Ozone is one of the important trace gases in the troposphere. Tropospheric ozone is a secondary pollutant formed by a series of photochemical reactions from NO x (oxides of nitrogen) and volatile organic compounds (VOCs) in the presence of solar radiation. It constitutes only 10 % of the total ozone in the atmosphere but is the main photochemical precursor of the hydroxyl radical (OH) which is the most active daytime oxi- dant in the troposphere (Bai 2010). Hence, absorption of light in the near-ultraviolet (UV) region (i.e., λ 0 290–310 nm) by ozone molecules initiates free radical chain reactions which oxidize many trace gases such as CO, CH 4 , VOCs, which otherwise would act as efficient greenhouse gases. Moreover, O 3 is a greenhouse gas by absorbing infrared, thus contributing to climate change (Wilson et al. 2007; Judith et al. 2008; Son et al. 2008). Surface ozone levels and its changes are of great interest since harmful effects of O 3 and positive trends of its concentration were established at a number of northern hemi- spheric locations (Scheel et al. 1997; Roemer and Tarasova 2002). The relation between reactants and products can be analyzed by systematically monitoring O 3 and NO x . The changes in local meteorological conditions, such as wind direction, wind speed, relative humidity, and temper- ature, can greatly affect chemical ozone generation, disper- sion and deposition on the surface causing variations in ozone concentrations (Duenas et al. 2002; Elminir 2005; Khiem et al. 2010). Therefore, analysis of the influences of the changes in meteorological conditions on variations in ozone is very helpful for better understanding variations in ozone concentrations. In recent years, meteorological effects on variations in surface ozone concentrations have been extensively studied (Tarasova and Karpetchko 2003; Tu et al. 2007; Cheng et al. 2007). These studies have shown that meteorological conditions can have significant impacts upon V. Singla : T. Pachauri : A. Satsangi : K. M. Kumari : A. Lakhani (*) Department of Chemistry, Faculty of Science, Dayalbagh Educational Institute, Dayalbagh, Agra 282110, India e-mail: anita.lakhani01@gmail.com V. Singla e-mail: s.vyoma@gmail.com T. Pachauri e-mail: triptiipachauri09@gmail.com A. Satsangi e-mail: srivastava_aparna@yahoo.com K. M. Kumari e-mail: maharajkumari.k@rediffmail.com Theor Appl Climatol (2012) 110:409–421 DOI 10.1007/s00704-012-0632-z