Diesel engines are used in wide range of applications, which include on-road and nonroad Vehicles, such as trucks, buses and construction equipment. Diesel exhaust emits harmful tiny particles known as fine particulate matter. Diesel engines are one of the largest sources of fine particulate matter as well as ozone-forming nitrogen oxides and toxic air pollutants. Fine particles and ozone pose public health problems.


The use of ultra-low sulfur diesel fuel in combination with pollution control equipment such as particulate matter filters can reduce particulate matter emissions by more than 90 percent.

Air Quality Onroad and Nonroad Vehicle Emission Standards
Westchester County is taking important steps to cleaner air by requiring on-road and nonroad diesel vehicles owned, leased and operated by or on behalf of the County, when used to perform County work to utilize Ultra Low Sulfur Diesel Fuel (sulfur content not to exceed 15 ppm) and Best Available Control Technology. The Westchester County Onroad and Nonroad Vehicle Emission Standards, Chapter 873, Article XIII, Section 873.1329 (the Law) was duly adopted on February 6, 2006 and became effective February 10, 2006.

While the Federal Government has set standards for new diesel engines (2007 and newer); existing diesel engines require retrofits of air pollution controls under this Law.

Information and Forms

For more information regarding diesel fuel and nonroad diesel vehicle and equipment, go to Environmental Protection Agency Diesel Fuel and Nonroad Equipment.