Urban air pollution: Input from car parking places

In the urban environment the car parking places are built in components. From the standpoint of air pollution view they can be treated as square pollution sources up to a point, because pollution is formed by mobile sources - vehicles. Pollution is emitted from cars coming into and leaving parking places, as well as during warming which is especially important in winter. Cold starts are the main constitution of all emissions emitted from parking places. Nevertheless, parked cars with hot engines also emit oil evaporations, especially if the cars are older then 10-12 years (84-88% of all vehicles in Riga belong to this group). In typical emission inventories the parking place and a collective garage are both included among the small sources of pollutants. A collective garage with the airconditioning is really a small source. Pollutants are emitted over the roof into the free atmosphere with good dispersion conditions. The impact of such a pollutant source on the quality of the surface layer of the atmosphere is small. Nevertheless, the parking places on the sides of streets and in close vicinity to the street give high pollution. It is therefore important to determine the pollutant emission of the parking place. The emission of pollutants is calculated as an average of the emission during the idle and slow speed regime of a car engine running. Emissions from car parking in a city make up a noticeable part from all the pollution caused by vehicles, especially when cold starts are taken into account. Our calculations show that all people living beside the street where cars are parked during day/night time suffer from higher concentrations of carbon oxides and volatile organic compounds (benzene).