An inverted-U relationship between GDP per capita and three urban transport-related emissions is tested (using data from 84 cities). Per capita urban transport-related emissions of CO, VHC, and NOx increase and then decline at observed income levels — a result driven by a similar inverted-U...

Automobile exhaust emission are an important feature of urban environment contamination due to movement of high traffic density and are widely believed to have detrimental effects on plant growth. The effects of automobile exhaust emission on the germination and early seedling growth performance...