Abstract
Vehicle emissions create corridors of increased carbon and nitrogen concentrations near highways that influence surrounding ecosystems. This study used the leaves of a variety of wild plant species and soil samples to examine the extent of total carbon (C) and total nitrogen (N) near highway M-2 and FSR in Punjab, Pakistan, in all four seasons of the year. Results showed significantly higher concentrations of C and N near roads in both plants and soils, indicating that a high proportion of vehicle derived C and N is deposited near roads. Compared to control samples, average soil C and N concentrations were increased by 174% and 519%, respectively, on the M-2 road. Similarly, 237% and 628% more C and N were measured in soil on FSR, respectively. The difference in mean concentrations of C and N among different seasons varied significantly. We inferred from these results that the level of C and N along roads depends upon the distance from the road, traffic volume, and seasonal variations. The raised level of C and N compounds could cause perilous impacts on the environment, especially to farmlands around major highways. Hence, farming activities like growing fruits and crops should be avoided near roads.