Predicting photochemical pollution in an industrial area Spyridon Lykoudis & Nikolaos Psounis & Anastasios Mavrakis & Anastasios Christides Received: 26 February 2007 / Accepted: 28 August 2007 / Published online: 11 October 2007 # Springer Science + Business Media B.V. 2007 Abstract In order to confront pollution events concerning the city of Elefsis, in the environmentally aggravated area of Thriassion Plain, an effort is undertaken to create a model forecasting maximal daily concentrations of NO x (NO 2 +NO), NO 2 and O 3 . The data analyzed were obtained from the Bureau of Pollution Control and Environments Quality based in Elefsis. The model in question uses hourly values of the pollutants as well as meteorological data recorded at the center of the city of Elefsis from 1993 to 1999. Three fitting methods are utilized, namely ordinary least squares, piecewise, and quantile regression. The verification and reliability of the forecasting models are based on the measurements of the year 2000. The results are considered to be satisfactory, with the forecasted values following the general tendencies. Keywords Photochemical pollution . Industrial pollution . Statistical models . Air quality prediction . Monitoring Introduction During the last decades, the dominating source of air pollution, in many cities, has changed from combus- tion of high sulphur-content coal and oil (causing elevated SO 2 and smoke concentrations) to a split between combustion of gaseous fuels in industrial processes and combustion related to motor vehicles. Ambient concentrations of air pollutants are quite variable both in time, following the temporal profile of pollutant emitting human activities, and in space. Such pollutants are nitrogen oxides, NO 2 and NO, emitted by various combustion processes and ground- level ozone (O 3 ), produced secondarily via chemical reactions between nitrogen oxides and non-methane volatile organic compounds in the presence of sunlight. Pollution levels at a certain urban location depend on the distance from dominating sources, and the Environ Monit Assess (2008) 142:279–288 DOI 10.1007/s10661-007-9925-6 S. Lykoudis (*) Institute for Environmental Research and Sustainable Development, National Observatory of Athens, I. Metaxa and V. Pavlou, 152 36 Palaia Pendeli, Athens, Greece e-mail: slykoud@meteo.noa.gr N. Psounis Systems of Energy and Environmental Management Co., Maiandrou 22, 192 00 Elefsis, Greece A. Mavrakis Department of Economic and Regional Development, Panteion University, 136 Syngrou Av., 176 71 Athens, Greece A. Christides Bureau of Pollution Control and Environmental Quality of the Development Association of Thriassion Plain, 50 Nikolaidou str., 192 00 Elefsis, Greece