There were nineteen automatic monitoring stations operating at sometime across the Tel-Aviv region during 1999–2006. These monitors measured half-hourly levels ofO3, NO2, SO2, CO, PM10 and PM2.5. Raw measurement data were obtained from the Air Quality Monitoring Network operated by Israeli Ministry of Environ- mental Protection and the Israel Electric Corporation. The number of pollutants measured by the stations varied. Table1 lists the number and type of station (i.e. ambient versus roadside) according to pollutant, missing values, differences between stations (represented by the standard deviation from the regional average), and distribution of the regional average concentrations.