Local-acting Air Pollutant Emissions from Road Vehicles

This chapter reviews the local impacts of air pollution emissions from roadways on air quality, human health, and the natural and built environments. These impacts are a global issue affecting urban areas around the world, including developed and developing nations, emphasizing the need to reduce emissions from roadway transport sectors around the world. Air pollutants emitted from vehicles, including particulate matter, nitrogen oxides, carbon monoxide, and hydrocarbons, are reactive (i.e. they have larger impacts on human health per unit of emissions compared to many other air pollution sources due to the proximity of the emissions and the chemical and physical natures of the emissions). These impacts affect public health, visibility, material damage, the surrounding ecosystems, and the quality of life for populations living near roadways. Although roadway emissions vary from region to region depending on the state of local fuel quality, vehicle technology, and emissions standards, general trends of roadway emissions and roadway impacts are summarized in this chapter. This summary includes the chemical composition of emissions from roadways, the contribution of mobile sources to local and regional air quality, the impacts on cultural heritage, and the health impacts of mobile sources. Existing regulations and projected trends in national standards for vehicle emissions are discussed and the implications of roadways for local environments are considered.