A special issue of selected papers from the 7th International Conference on Air Quality - Science and Application : Istanbul, 24-27 March 2009

The study of urban and regional air quality remains as important as ever. In 2007, the number of people living in urban areas exceeded the number living in rural areas for the first time in history. Further continuation of this trend, together with the aging of populations especially in the developed countries, will expose more people to potentially more serious effects of air pollution than ever before. Increased awareness of the issues surrounding both urban and regional air quality has led to the rise of so-called “chemical weather forecasting” systems, in which forecasts of air quality are disseminated as routinely as standard operational weather forecasting products. These chemical weather forecasts often perform several roles, such as, for example serving to inform the public of potential risks, helping the local authorities in case of serious air pollution episodes and in numerous research applications, e.g., as an aid in the planning of observational field campaigns.