Air pollution is defined as those substances in the air at greater than ambient concentrations which have adverse effects on people, animals, plants or inanimate objects.
Sources of Outdoor Air Pollution:
The predominant source of air pollution in the US is the exhaust from the fuel combustion process used to power motor vehicles for transportation.
In the US, essentially all transportation is powered by gasoline or diesel fuels. Because the burning of diesel fuel results in high levels of particulate matter emission, which is associated with asthma development, the study and reduction of diesel exhaust provides opportunity to impact pediatric asthma.
Diesel fuel is commonly burned in engines powering heavy vehicles such as trucks and buses due to its lower price. However, it also is less efficient in its combustion and results in the production of many irritants and carcinogens. Diesel engine exhaust includes:
- nitrogen compounds
- carbon dioxide
- carbon monoxide
- sulfur compounds
- low-molecular-weight hydrocarbons
- water vapor
- 1,3 butadiene
- polycyclic aromatic hydrocarbons (PAHs)
- elemental carbon
Diesel exhaust emissions contribute to the development and exacerbation of asthma because of both the numerous chemical irritants and the large volume of small particulate matter.
Cleveland Clinic Health System 2002
Robbins, Pathogenesis of Human Disease
Adam Ratner, M.D., Children's Hospital of Philadelphia, Philadelphia, PA