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The construction industry currently relies heavily on diesel engines to power their machines. These diesel-powered engines are a significant source of air pollutants such as particulate matter (PM) and nitrogen oxides (NOx).

Air Pollutants

PM is an irritant that results from the incomplete combustion of diesel fuel. It contributes to respiratory and cardiovascular illnesses that may adversely affect children, the elderly and those with pre-existing respiratory conditions. Exposure to PM is known to cause asthma, heart attacks, strokes, lung cancer, and premature death.

NOx contributes to the formation of ground level ozone, which is a respiratory irritant that poses a health hazard for both healthy adults and individuals with pre-existing respiratory conditions.

According to the South Coast Air Quality Management District (SCAQMD), heavy duty diesel trucks and off-road construction equipment operating in Southern California are major sources of PM and NOx emissions and are also among the sources identified for the greatest emission reduction potential.

Green Construction

In an effort to help mitigate diesel emissions in the South Coast Air Basin, local agencies such as the Port of Long Beach, Port of Los Angeles and Los Angeles Airports have developed green construction policies and guidelines.

On August 4, 2011 Metro adopted the Green Construction Policy (GCP) and committed to using greener, less polluting construction equipment and vehicles; and implementing best practices to reduce harmful diesel emissions on all Metro construction projects performed on Metro properties and rights of way.