Estimating Summer Emissions from Land Transportation Vehicles Moving Along the Urban Roads

The industrial and transport effect on the environment is distinguished most significantly by the formation of technogeneous geochemical anomalies in the urban landscape. This study was conducted within the boundaries of urban agglomeration (Penza city) for two years (2014 and 2015) during the summer (June to August). To determine the effect that the distance from road and the amount of heavy metal emissions have, samples were extracted at a distance of 10, 20, 30, 40, 50 and 60 metres from the roadway. There were three sampling points at each sampling line, with a 3 to 4-metre space between them. The year-long measurements make up a number over 20.000. In Penza, the flow of traffic typically varies between 3 and 3943 cars per hour. When produced in significant amounts, heavy metal emissions from vehicles—exhaust emissions (Pb, Cu, Ni), particulate matter emissions (Cu, Ni, Zn), emissions from plastics and paint (Zn, Cd), and tirewear emissions (Zn)—accumulate in the roadside area, transform and further migrate along the food chains. All road categories show a significant elevation in the background and emission limit values for all heavy metals studied. The most dramatic rise was recorded for Cu and it was 5.09- to 19.11-fold. The concentration of Ni, Zn and Pb exceeds the acceptable rate 1.17- 8.79-fold. The concentration of carbon monoxide decreases with distance from the road. Street ranking by car hazard shows that all main urban streets with regulated traffic are category 1 hazard sources of emission, mainly due to lead compounds (%). Between spring and summer, the traffic flow increases 1.3- to 2-fold and the hazard category of roads rises (under 1.5-fold). Significant changes in the traffic infrastructure and vehicle replacement compensate for the negative impact of vehicles on air quality in Penza, which was initially caused by the increase in the number of vehicles on the road and by the subsequent overload of the transport network. The increase in the queue length and time did not entail the emission growth. On the contrary, since 2014, Penza has been showing a decreasing trend and since 2015, the total amount of emissions from motor vehicles has been remaining at a stabilized point.