The following acronyms are commonly referred to in the Philadelphia Diesel Difference website and materials.

AMS: Air Management Service is Philadelphia's regulating agency on air quality issues and part of the city's Health Department


B20: Most common biodiesel blend, comprised of 20% biodiesel and 80% petrodiesel

B100: Pure biodiesel that is nontoxic and biodegradable


CARB: The California Air Resource Board


CMAQ: Congestion Mitigation and Air Quality is a federal program to reduce transportation emissions in regions that are not in attainment of the Clean Air Act.


CO: Carbon Monoxide


CNG: Compressed Natural Gas


DOC: Diesel Oxidation Catalyst


DPF: Diesel Particulate Filter


DVRPC: Delaware Valley Regional Planning Commission is the area's metropolitan planning organization


EPA: U.S. Environmental Protection Agency


HAP: Hazardous Air Pollutant


HC: Hydrocarbons are a precursor to ozone and a serious air pollutant. Emissions result from incomplete fuel combustion and fuelevaporation.


IRT: Idle Reduction Technologies


LNG: Liquified Natural Gas (commonly called propane)


MDC: Mid-Atlantic Diesel Collaborative


MERCs: Mobile source Emission Reduction Credits


NMHC: Non-Methane Hydrocarbons


NOx: Nitrogen Oxides


PADEP: Pennsylvania Department of Environmental Protection


PDD: Philadelphia Diesel Difference


PM: Particulate Matter


PM10: Particulate matter with a mass median aerodynamic diameter of less than 10 micrometers. They are among the smaller particles, suspended in the air and easily inhaled into the deep lungs. Also known as "course" particulates.


PM2.5: Particulate matter with a mass median aerodynamic diameter of less than 2.5 micrometers. Also known as "fine" particulates.


RFP: Request For Proposals (when an entity with funds asks that applications be submitted for consideration)


SCR: Selective Catalytic Reduction


PPM: parts per million


ULSD: Ultra -Low Sulfur Diesel


VOC: Volatile Organic Compounds