Assessment of impact of vehicle traffic conditions: urban, rural and highway, on the results of pollutant emissions inventory

The use of motor vehicles varies considerably under distinct traffic conditions: in cities, outside cities as well as on motorways and expressways. The impact of road traffic on the natural environment has been studied for many years, including in terms of the nature of the operation of motor vehicles. This problem is particularly important in highly urbanized areas, where traffic congestion is the source of increased emissions of harmful compounds contained in exhaust gases. For this reason, many cities have traffic restrictions, especially for those cars that do not meet the most stringent emission standards. Environmental protection is the driving force behind the development of modern combustion engine supply systems, which allow for proper control of the combustion of petroleum-derived fuels. The exhaust gas cleaning systems in the form of catalytic converters or particulate matter filters are also playing a very important role. Considerable differences in internal combustion engine operating states, both static and dynamic, result in important differences in pollutant emissions. Likewise, the national annual pollutant emission is affected by the share of distances travelled by vehicles under various traffic conditions. At the same time, it is very difficult to estimate exhaust emissions from road transport sources. Very interesting method of emission estimation is the application of the data included in the emission inventory which are a valuable source of information on exhaust emissions under various operating conditions. In the present study, the annual pollutant emissions were analyzed: at a national level (total pollutant emission) and in distinct traffic conditions. There were found large differences between individual pollutants’ shares in the emissions from vehicles under the tested traffic conditions. This is particularly evident for nitrogen oxides with the highest emission share outside cities, as opposed to other substances with the highest emission shares in cities, where traffic congestion is taking place.