AERCO — Area Emission Reduction Credit Organizations

ALVW — Adjusted Loaded Vehicle Weight

AQI — Air Quality Index

AQM — Air Quality Model


BA — Baseline Activity

BACT — Best Available Control Technology

BAP — Bureau of Air Policy

BAQC — Bureau of Air Quality Control

BART — Best Available Retrofit Technology

BCCA — Business Coalition for Clean Air

BER — Baseline Emission Rate

BPA — Beaumont/Port Arthur ozone nonattainment area


CAA — Clean Air Act of 1990

CAAA — Clean Air Act Amendments of 1990

CARE — Clean Air Responsibility Enterprise

CEM — Continuous Emission Monitor

CMAQ — Congestion Mitigation/Air Quality funds under FAST Act

CMSA — Consolidated Metropolitan Statistical Area (the Houston-Galveston-Brazoria CMSA consists of the Houston PMSA [Chambers, Fort Bend, Harris, Liberty, Montgomery and Waller Counties], the Galveston-Texas City PMSA [Galveston County], and the Brazoria PMSA [Brazoria County].

CNG — Compressed Natural Gas

CO — Carbon Monoxide

CO2 — Carbon Dioxide

COAST — Coastal Oxidant Assessment for Southeast Texas

COG — Council of Governments

COPD — Chronic Obstructive Pulmonary Disease


DERC — Discrete Emission Reduction Credit

DFW — Dallas/Fort Worth ozone nonattainment area


EBTA — Emissions Banking and Trading of Allowances (SB7)

EBTP — Emissions Banking and Trading Program

EGF — Electric Generating Facility

EPA — Environmental Protection Agency

EPN — Emission Point Number

ERC — Emission Reduction Credit

ERP — Emission Reduction Plan

ESAD — Emission Specifications for Attainment Demonstration

ESL — Effects Screening Level

ETR — Employer Trip Reduction


FAST — Fixing America's Surface Transportation

FCAA — Federal Clean Air Act

FCFF — Federal Clean Fuel Fleet

FHWA — Federal Highway Administration

FIN — Facility Identification Number

FTA — Federal Transit Administration


GHP — Greater Houston Partnership

GIS — Geographic Information Systems

GVWR — Gross Vehicle Weight Rating


HAP — Hazardous Air Pollutant

HC — Hydrocarbons

HCOEM — Harris County Office of Emergency Management

HDDV2b — Heavy-Duty Diesel Vehicles Class 2b (8,501-10,000 lbs. GVWR)

HDDV3 — Heavy-Duty Diesel Vehicles Class 3 (10,001-14,000 lbs. GVWR)

HDDV4 — Heavy-Duty Diesel Vehicles Class 4 (14,001-16,000 lbs. GVWR)

HDDV5 — Heavy-Duty Diesel Vehicles Class 5 (16,001-19,500 lbs. GVWR)

HDDV6 — Heavy-Duty Diesel Vehicles Class 6 (19,501-26,000 lbs. GVWR)

HDDV7 — Heavy-Duty Diesel Vehicles Class 7 (26,001-33,000 lbs. GVWR)

HDDV8a — Heavy-Duty Diesel Vehicles Class 8a (33,001-60,000 lbs. GVWR)

HDDV8b — Heavy-Duty Diesel Vehicles Class 8b (>60,000 lbs. GVWR)

HDDBS — Heavy Duty Diesel School Buses

HDDBT — Heavy Duty Diesel Transit and Urban Buses

HDGB — Heavy Duty Gasoline Buses

HDGV2b — Heavy-Duty Gasoline Vehicles Class 2b (8,501-10,000 lbs. GVWR)

HDGV3 — Heavy-Duty Gasoline Vehicles Class 3 (10,001-14,000 lbs. GVWR)

HDGV4 — Heavy-Duty Gasoline Vehicles Class 4 (14,001-16,000 lbs. GVWR)

HDGV5 — Heavy-Duty Gasoline Vehicles Class 5 (16,001-19,500 lbs. GVWR)

HDGV6 — Heavy-Duty Gasoline Vehicles Class 6 (19,501-26,000 lbs. GVWR)

HDGV7 — Heavy-Duty Gasoline Vehicles Class 7 (26,001-33,000 lbs. GVWR)

HDGV8a — Heavy-Duty Gasoline Vehicles Class 8a (33,001-60,000 lbs. GVWR)

HDGV8b — Heavy-Duty Gasoline Vehicles Class 8b (>60,000 lbs. GVWR)

HGA — Houston-Galveston-Brazoria non-attainment area

H-GAC — Houston-Galveston Area Council

HGCCC — Houston Galveston Clean Cities Coalition

HIRI — Heat Island Reduction Initiative

HOV — High-Occupancy Vehicle

HRM — Houston Regional Monitoring Corporation


ILEV — Inherently Low Emission Vehicle

I/M — Inspection/Maintenance program (vehicle emissions control)

ISTEA — Intermodal Surface Transportation Efficiency Act of 1991


LAER — Lowest Achievable Emission Rate

LDDV — Light-Duty Diesel Vehicles (passenger cars)

LDDT12 — Light-Duty Diesel Trucks 1 and 2 (0-6,000 lbs. GVWR)

LDDT34 — Light-Duty Diesel Trucks 3 and 4 (6,001-8,500 lbs. GVWR)

LDGV — Light-Duty Gasoline Vehicles (passenger cars)

LDGT1 — Light-Duty Gasoline Trucks 1 (0-6,000 lbs. GVWR, 0-3,750 lbs. LVW)

LDGT2 — Light-Duty Gasoline Trucks 2 (0-6,000 lbs. GVWR, 3,751-5,750 lbs. LVW)

LDGT3 — Light-Duty Gasoline Trucks 3 (6,001-8,500 lbs. GVWR, 0-5,750 lbs. ALVW)

LDGT4 — Light-Duty Gasoline Trucks 4 (6,001-8,500 lbs. GVWR, 5,751 lbs. and greater ALVW)

LEV — Low Emission Vehicle

LNG — Liquefied Natural Gas

LOA — Level of Activity

LPG — Liquefied Propane Gas

LVW — Loaded Vehicle Weight


MACT — Maximum Achievable Control Technology

MAERT — Maximum Allowable Emission Rate Table

MC — Motorcycles (gasoline)

MDERC — Mobile Discrete Emission Reduction Credit

MECT — Mass Emission Cap and Trade

MERC — Mobile Emission Reduction Credit

METRO — Metropolitan Transit Authority of Harris County

MOA — Memorandum of Agreement

MPO — Metropolitan Planning Organization

MTBE — Methyl Tertiary Butyl Ether

MTP — Metropolitan Transportation Plan


NAAQS — National Ambient Air Quality Standards

NAMS — National Air Monitoring Stations

NESHAPs — National Emission Standards for Hazardous Air Pollutants

NLEV — National Low Emission Vehicle

NO2 — Nitrogen Dioxide

NOx — Nitrogen Oxides

NSPS — New Source Performance Standards

NSR — New Source Review

NWS — National Weather Service


O2 — Oxygen

O3 — Ozone

OTAG — Ozone Transport Assessment Group


Pb — Lead

PCC — Program Compliance Credit

PM2.5 — Particulate Matter less than 2.5 microns in size

PM10 — Particulate Matter less than 10 microns in size

PMT — Personal Miles Traveled

PPB — Parts per Billion

PPM — Parts per Million

PSD — Prevention of Significant Deterioration


RACT — Reasonably Available Control Technology

RAQPC — Regional Air Quality Planning Committee

RCAP — Regional Commute Alternatives Program

RFG — Reformulated Gasoline

RTP — Regional Transportation Plan


SA — Strategic Activity

SER — Strategic Emission Rate

SIP — State Implementation Plan

SLAMS — State or Local Air Monitoring Station

SO2 — Sulfur Dioxide

SOCMI — Synthetic Organic Chemistry Manufacturing Industry

SOV — Single Occupant Vehicle

SOx — Oxides of Sulfur

SULEV — Super Ultra Low Emission Vehicle

SUV — Sport Utility Vehicle


TAC — Technical Advisory Committee

TAFF — Texas Alternative Fuel Fleet Program

TCAA — Texas Clean Air Act

TCEQ — Texas Commission on Environmental Quality (Former TNRCC)

TCMs — Transportation Control Measures

TCP — Transportation Control Plan

TDM — Transportation Demand Management

TEA21 — Transportation Equity Act for the 21st Century (replaces ISTEA)

TERP — Texas Emission Reduction Plan

TIP — Transportation Improvement Program

TMA — Transportation Management Area

TMO — Transportation Management Organization

TNRCC — Texas Natural Resource Conservation Commission (now TCEQ)

TOG — Total Organic Gases

TPC — Transportation Policy Council

TPD — Tons per Day

TPY — Tons per Year

TxAQS 2000 — Texas 2000 Air Quality Study

TxDOT — Texas Department of Transportation (formerly Texas Highway Department)


UAM — Urban Airshed Model

ug — Micrograms or 10-6 grams

ULEV — Ultra Low Emission Vehicle

USDOT — United States Department of Transportation


VMEP — Voluntary Mobile Emission Program

VMT — Vehicle Miles Traveled

VOC — Volatile Organic Compound



ZEV — Zero Emission Vehicle