Determination of air quality from mobile sources in the city of Izmir

The scope of this study is to determine the air pollution levels from on-road mobile sources inthe city center of Izmir which is the third greatest metropolis of Turkey. Within the scope ofthe study, 19 main streets were selected to count and classify the vehicles due to theirlocations and high traffic densities. The vehicles were estimated in other main streets (n=46)by using some additional methods such as high resolution satellite images and video camerarecords at crossroads. Vehicle counting was done at the selected points in 19 streets withportable vehicle classifier systems. The traffic activity was determined separately on eachstreet but simultaneously for both directions (departure and arrival) during a week.Furthermore, the ambient air quality levels were also measured in the selected streets by amobile air quality monitoring station. Major pollutants and several meteorological parameterswere observed for approximately 10 days in each street during the measurement campaigns inboth summer and winter in order to obtain hourly, daily, weekly and seasonal variations of airquality. These results were also used to validate the dispersion model used in the study.The emissions for 5 pollutants (nitrogen oxides, carbon monoxide, sulfur dioxide, nonmethanetotal volatile organic compounds and particulate matter were calculated by using thetraffic activity data on the streets and the selected emission factors from literature. It was alsofound that these emissions cause serious air quality levels for human health in the atmosphereof the city.The CALMET/CALPUFF modeling system was used to calculate the dispersion of pollutantsfrom mobile sources in the city. Model runs were done only for the peak hours of severalepisodes in the year 2006 in order to find the contribution of traffic sector to urban air qualityin these periods. The maximum hourly concentrations predicted by the model in summermornings.