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Natural Resources / Air Quality

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Natural Resources / Air Quality

AACOG's Natural Resources Department addresses air quality issues in the region by bringing together stakeholders from all interests - government, industry, business, and residents - to better understand ozone and other air pollutants, and encourage regional collaboration in support of air quality improvement.

The air quality technical projects of AACOG include air pollution monitoring, data analysis, emission inventory development, modeling, and reporting. The air quality outreach and education programs of AACOG address a wide range of topics, including fuels and vehicles, energy efficiency, ride sharing, vehicle operation and maintenance, and the Ozone Action Day Alert program.


AACOG’s Natural Resources Department addresses air quality issues in the region by bringing together stakeholders from all interests - government, industry, business, and residents - to develop air pollution reduction plans that benefit our quality of life.

Guided by the Air Quality Committee, which represents different sectors of the community, staff members conduct technical projects that provide the data analysis necessary for air quality planning.

Projects & Programs

AACOG’s air quality and outreach programs complement its technical work by increasing knowledge of and encouraging participation in pollution reduction measures.

Coming Soon: We will be launching a smoking vehicle reporting program that is designed to inform vehicle owners their vehicle may be creating excessive smoke and emitting pollutants, which are harmful to our health and environment.

Ambient Air Quality Monitoring

AACOG has been monitoring ozone in the region since 2002 and currently owns and operates seven ozone monitors, two nitrogen oxide (NOx) monitors, and a volatile organic compound (VOC) monitor. NOx and VOCs are precursors to ozone, meaning they react chemically to form ozone, as ozone is not emitted directly.

Monitoring air quality allows us to develop a better understanding of the behavior of air pollutants - how they form, where they go, where they come from - and how to best reduce their presence in our airshed.

Alamo Area Clean Cities

The Alamo Area Clean Cities Coalition works with vehicle fleets, fuel providers, community leaders, and other stakeholders to save energy and promote the use of domestic fuels and advanced vehicle technologies in the transportation sector. Learn more.

Regional Energy Management

AACOG is partnering with the State Energy Conservation Office (SECO) to provide resources to assist in the implementation of energy efficiency and energy management programs. This will include trainings, workshops, and assistance with other energy related issues. Learn More.

Emission Inventories

Emissions Inventories By Year



Atmospheric Studies and Other Resources

NOAA Weather


NOAA GOES East Satellite Imagery: Visible, IR and Water Vapor

NASA GMAO Experimental Forecast Suite: High resolution visualizations of aerosol and gases passing across Texas. The Asian contribution is clearly shown

NASA GMAO Experimental Forecast Suite

Naval Research Lab Monterey Aerosol Page: Low resolution aerosol and SO@ forecasts visualizations

NOAA Upper Air Soundings

USDA UV-B Network (Also Total Ozone, PAR and Optical Depth): One of 34 instrument arrays is at Texas Lutheran University in Seguin

Total Column Water Vapor (Precipitable Water): 4 Texas sites, including San Antonio (TXAN) and Seguin (TXSE) 

Air Quality Outreach & Education Programs

Ground Level Ozone and Air Quality

In the 13-county Alamo region surrounding San Antonio, our major air pollutant is ground-level ozone. Unlike ozone which is high up in the earth’s atmosphere and protects us from the more harmful rays of sunlight, ozone that forms in the air we breathe is harmful to humans and other living things.

Ground-level ozone forms when nitrogen oxides, which are found in vehicle exhaust, mix with volatile organic compounds, which are found in gasoline fumes. Nitrogen oxide and volatile organic compounds mix together in intense sunlight to form ground-level ozone. Ground-level ozone typically forms in this region between March and November, when sunlight tends to be the strongest. Thus, the period of time from March through November is referred to as the Ozone Season.

Update on Planning Activities for the Bexar County Ozone Nonattainment Area

Anti-Idling Ordinance Resources

Click here for the Anti-Idling Ordinance Overview

Click here for the Idling Fact sheet

If you have any questions or feedback on the proposed ordinance, please contact Nicholas Jones via email or (210) 918-1299.

Funding Mechanisms for Idle Reduction

Funding opportunities exist to reduce the amount of idling necessary during normal operation, and several of these programs are listed below.

1) Railroad Commission - Alternative Fuels Clean School Bus Replacement Program

2) Texas Emissions Reduction Plan (TERP) -
 TERP is administered by the TCEQ and includes a number of voluntary financial incentive programs to help improve the air quality in Texas. In particular, the Emissions Reduction Incentive Grants (ERIG) Program provides funding for eligible projects in affected counties to offset the incremental costs associated with the activities to reduce NOx emissions from high-emitting mobile sources. For information, visit, call 800-919-TERP (8377), or email.

3) EPA SmartWay Transport Partnership - Innovative Financing SmartWay provides information on several lenders that offer loans to owner-operators and small trucking companies to help pay for technologies that will save fuel while reducing pollution. These loans offer affordable monthly payment plans. The Small Business Administration-approved Lenders offer affordable monthly principal and interest monthly payments with no collateral required for loans ranging from $5,000 to $25,000. For information, visit

4) National Idling Reduction Network News -
 The National Idling Reduction Network brings together trucking and transit companies, railroads, equipment manufacturers, local, State, and federal government agencies (including regulators), and national research laboratories to identify consistent, workable solutions to heavy vehicle idling for the entire United States. In addition, regular newsletters provide information on current local and national funding opportunities that may support idle-reduction technologies. For information visit:

Electrified Truck Stops
The closest electrified truck stop for large heavy-duty vehicles is at:

Flying J Travel Plaza - San Antonio
1815 N Foster Rd
San Antonio, TX 78244

Phone: (210) 666-2266
Directions: I-10, Exit 583
Brand: Shorepower
Number of Bays: 24
Access: Public - see hours
Hours: 24 hours daily
Payment: Gift Card, Discover, VISA, MasterCard

Technology Options

EPA estimates that one heavy-duty truck could save as much as 1,830 gallons of fuel each year simply by eliminating unnecessary idling. With diesel fuel hitting an all time high of $4.80 per gallon in June 2008, and with trends fluctuating around $4.10 per gallon with no significant decrease projected, total savings could add up significantly by simply reducing idling. Fortunately, this sector benefits from a wide variety of technological solutions to aid in accomplishing just that. By utilizing the technologies described below, a driver can enjoy the same amenities with the added benefit of reducing pollution and fuel consumption. These idling alternatives are divided into two categories: on-board and on-site.

On-Board Options On-board options enable a driver to be comfortable in the cab without operating the main engine of the vehicle. These devices are advantageous because they can be used nearly anywhere and do not require new infrastructure. Several types of on-board technology are available:

Automatic Shut-Down Device: Enables programming of the engine to turn on and off automatically after a predetermined time limit or at a certain temperature setting.

Auxiliary Power Unit or Generator: A second, smaller engine that provides a power supply for a wide range of driver needs, including climate control and electrical power for computers or other equipment, while allowing the main engine to remain off. Also known as APU.

Battery-Powered or Alternative-Power Device: Provides stored energy for heating and cooling. It does not produce any emissions and lasts for the duration of the battery charge.

Fuel-Operated Heater: Commonly known as a bunk heater, it circulates heated coolant to the vehicle’s regular heater system, which allows the sleeper cab to be heated without idling the main engine.

Thermal Storage System: Also known as an evaporative cooler, it holds energy in cold storage as the truck is driven. When the engine is turned off, it provides air conditioning.

If you have any questions or feedback on the proposed ordinance, please contact Nicholas Jones via email or (210) 918-1299.

Atmospheric Studies and Other Resources

NOAA Weather


NOAA GOES East Satellite Imagery: Visible, IR and Water Vapor

NASA GMAO Experimental Forecast Suite: High resolution visualizations of aerosol and gases passing across Texas. The Asian contribution is clearly shown

NASA GMAO Experimental Forecast Suite

Naval Research Lab Monterey Aerosol Page: Low resolution aerosol and SO@ forecasts visualizations

NOAA Upper Air Soundings

USDA UV-B Network (Also Total Ozone, PAR and Optical Depth): One of 34 instrument arrays is at Texas Lutheran University in Seguin

Total Column Water Vapor (Precipitable Water): 4 Texas sites, including San Antonio (TXAN) and Seguin (TXSE) 

Alternative Fuels and Vehicles

Alternative fuels and vehicles form the cornerstone of the Clean Cities program. They are a valuable tool for reducing air pollution and greenhouse gases, protecting public health, and contributing to economic development. The Clean Cities Program is fuel neutral and works with fleets to provide them with the most accurate resources and information available on alternative fuels. Visit the Department of Energy's Alternative Fuels Data Center to find an alternative fueling station in your area.

Alternative Fuels

Today more than a dozen alternative fuels are in production and use or under development. Although government fleets and private fleets are the primary users of these fuels, consumers have an increasing interest in them. Using these fuels in place of conventional fuels is critical to reducing U.S. dependence on foreign oil and emissions that harm air quality.

Some alternative fuels, as defined by the Energy Policy Act of 1992 (EPAct), that are commonly used and commercially available for vehicles include:

Follow the links for more information from the Alternative Fuels Data Center

Alternative Fuel Vehicles

An alternative fuel vehicle (AFV) is a dedicated, flexible fuel, or dual-fuel vehicle designed to operate on at least one alternative fuel. An advanced vehicle combines new engine, power, or drivetrain systems to significantly improve fuel economy.

Advanced Technology Vehicles

Alternative Fueling Station Locator

Locate Alternative Fuel

Ozone 101

Ozone 101

Ozone is a molecule comprised of three oxygen atoms instead of the two atoms that gaseous oxygen usually contains. When it is present in the air at ground level, ozone is the main component of the type of air pollution referred to as smog. According to the Texas Commission on Environmental Quality (TCEQ), ground-level ozone is the most common air pollutant in Texas and the nation.

Ozone is not emitted directly into the air by any one pollution source, but is formed through chemical reactions between natural and man-made emissions of volatile organic compounds (VOCs) and nitrogen oxides (NOx) in the presence of sunlight. These gaseous compounds mix in the air, and when they interact with sunlight, ozone is formed. Sources of VOC and NOx pollutants include automobiles, gas-powered engines, refineries, chemical manufacturing plants, solvents used in dry cleaning and paint, and wherever natural gas, gasoline, diesel fuel, kerosene, and oil are used as fuel.

Ozone pollution is mainly a daytime problem during the summer months because warm temperatures and sunlight play a role in the formation of high ground-level ozone. For the San Antonio region, the ozone season is from March through November, when temperatures are at their highest and the days are longest. During high temperatures, when the sunshine is strong and winds are weak, ozone can build up to harmful levels.

Isn’t Ozone Good for Us?

The word ozone creates confusion because it can be either helpful or harmful, depending on where it is located. Ozone occurs in two layers of the atmosphere. Up high in the earth’s atmosphere, ozone protects us from the sun’s harmful ultraviolet rays. Down low, in the air we breathe, ozone can negatively impact human and animal health and damage vegetation.

Ozone can irritate breathing passages and cause shortness of breath, wheezing, and coughing. It can cause or make respiratory illnesses such as asthma worse. Individuals most susceptible to ground-level ozone are children (whose lungs are still developing), those who already have respiratory ailments such as asthma or emphysema, and those who work or exercise strenuously outside for extended periods of time.

What Can We Do About It?

The Texas Commission on Environmental Quality (TCEQ) forecasts days when conditions are likely to produce high levels of ozone. TCEQ encourages people to take voluntary action on those days to both reduce pollution and protect their health.

Since automobiles are a major culprit in ozone formation in our region of Texas, it is helpful to limit our driving on Ozone Action Days, when ozone pollution is predicted to be high. Actions like carpooling, riding the bus, riding a bicycle, combining errands, avoiding rush hour traffic, and packing a lunch to eat in rather than going out can all help reduce air pollution. Waiting to refuel our vehicles or mow our lawns until after 6:00 p.m. can also be helpful.

While such actions are particularly important on Ozone Action Days, our daily choices are also important in improving air quality. Below are some actions that not only improve the air but also save gas money:

  • Share a ride to work or school instead of driving alone
  • Walk or bike—especially for trips of a mile or less
  • Avoid lunch-time trips–take your lunch to work or school
  • Combine errands into one trip
  • Drive the speed limit or less
  • Avoid waiting drive-through lanes—go inside instead
  • Keep your vehicle properly tuned and your tires properly inflated for improved gas mileage

Businesses Can Help Improve Air Quality By:

  • Shifting work schedules to help employees avoid rush-hour traffic
  • Allowing employees to telecommute (work from home)
  • Offering reimbursement for bus passes
  • Encouraging employees to carpool to lunch and meetings;
  • Scheduling meetings that don't require driving (for example, teleconferencing)
  • Offering incentives, such as premium parking spaces, for employees who carpool
Ozone Action Day Alerts

What is it?

An Ozone Action Day Alert is issued by the State when weather conditions are expected to favor high ozone the following day. An email or text notification is sent out when ozone pollution is predicted to reach unhealthy levels for sensitive groups, including those with respiratory ailments, young children, older people, and those who spend prolonged periods outdoors. Parents, teachers, school administrators, nurses, and anyone else can sign up to receive email alerts from the Alamo Area Council of Governments for Ozone Action Days. 

Why should I do it?

When alerted of an Ozone Action Day, parents can take steps to reduce their child’s exposure to harmful air pollutants, such as reducing their child’s time spent outdoors, taking frequent breaks and monitoring their breathing, or changing their outdoor time to the morning, before much ozone has had a chance to form. Residents can also take steps to reduce pollution by altering certain behaviors, including avoiding refueling vehicles or mowing lawns until after 6 p.m., or limiting the time idling in your vehicle.

How do I sign up?

Click here to receive Ozone Action Day Alerts. You will only receive emails when an Ozone Action Day Alert is issued by the State. These alerts will include steps that you can take to reduce emissions that contribute to ozone.

Funding Programs

Laws and Incentives Search

Find federal and state laws and incentives for natural gas vehicle fuels and vehicles, air quality, fuel efficiency, and other transportation-related topics: DOE Laws and Incentives Search

How to Claim Federal Tax Credits for Natural Gas Fuels and Fueling Infrastructure:

The Railroad Commission of Texas has provided us the forms and instructions to claim the tax credits for natural gas fuels (CNG & LNG) and refueling infrastructure. Please click on the below fact sheets for general information about how to claim the credits. For more details and questions, contact the IRS number at the bottom of the sheets.

Texas Commission on Environmental Quality Funding Programs

The Texas Emissions Reduction Plan (TERP) provides financial incentives to eligible individuals, businesses or local governments to reduce emissions from polluting vehicles and equipment. To view available incentives please visit the TCEQ TERP Information Page.

Go Electric Day

San Antonio Drive Electric Day provides information on electric vehicles (EVs) in a friendly and engaging setting. Hear from local EV owners and meet other EV enthusiasts while checking out booths from our partners at CPS Energy, the City of San Antonio's Office of Sustainability, Bexar County, and more. This annual free public event is at the historic Pearl Brewery’s Farmers Market located at 312 Pearl Parkway, San Antonio, TX 78215.

San Antonio Drive Electric is one of more than 300 National Drive Electric Week (NDEW) events held coast-to-coast. NDEW is organized nationally by Plug In America, the Sierra Club, and the Electric Auto Association. Alongside its public and private sector stakeholders, the Alamo Area Clean Cities Coalition supports the promotion and adoption of hybrid and plug-in electric vehicles as an alternative to gasoline-powered vehicles. Since its federal designation in 1999, Clean Cities’ efforts and promotion of alternative fuels have resulted in the displacement of an estimated 3.5 million gallons of gasoline per year.

Reasons to Go Electric 


Some electric vehicles are more expensive to purchase than conventional gasoline-powered cars, however their initial costs can be offset by federal tax credits and fuel cost and maintenance savings. Electric vehicles are cheaper to maintain than gasoline-powered vehicles. Electric Vehicles (EVs) require no oil changes and have ten fewer moving parts than a gasoline-powered car (engine, transmission, spark plugs, valves, tailpipe, distributor, starter, clutch, muffler, or catalytic converter). Additionally, driving on electricity is about five times cheaper than fueling with gasoline, especially given the volatility of gas prices. Use the Department of Energy's Vehicle Cost Calculator to compare lifetime ownership costs of individual models of Hybrid Electric Vehicles (HEVs), Plug-in Hybrid Electric Vehicles (PHEVs), EVs, and conventional vehicles.


The average gasoline-powered passenger vehicle emits about 4.7 metric tons of carbon dioxide (CO2) every year, contributing to poor air quality. In addition to CO2, gasoline-powered vehicles also emit methane, hydrofluorocarbons, and nitrogen oxides - which contribute to the production of harmful ground-level ozone, the most common form of air pollution in Greater San Antonio. By contrast, all-electric vehicles (EVs) produce zero tailpipe emissions, thus preserving the quality of our air by reducing smog, haze, and health problems. Even when considering the cost of and emissions produced by electricity usage, on average, electric vehicles still produce fewer lifetime emissions. In Texas, electric vehicles as a whole reduce annual emissions, compared to gasoline-powered vehicles, by more than 6,500 pounds.

Power and performance

Contrary to the common myth, electric vehicles are built for more than fuel efficiency, but power and performance as well. Electric vehicles are smooth and quiet, and their high torque – even at low speeds – provides instant accelerator response, and also better performance in snow. Whereas gasoline-powered vehicles operate at about 30% efficiency (with approximately 70% of their energy eaten by heat, sound, friction, and pollutants), electric vehicles operate at 90% efficiency because of instantaneous power through torque.

Batteries and infrastructure availability

Since the rollout of the modern electric car, battery design and life has improved immensely. Several manufacturers of plug-in electric vehicles offer 8-year/100,000 miles battery warranties, but studies from the Department of Energy’s National Renewable Energy Laboratory (NREL) indicate that today’s batteries may last 12 – 15 years in moderate climates.

In addition to at-home charging facilities and extended-range models, there are almost 100 public EV charging stations in San Antonio and surrounding communities. The Department of Energy’s Alternative Fuels Data Center helps users locate EV charging stations, public and private, and helps plan routes.

Air Quality and Health

The term “air pollution” refers to chemicals or particles in the air that can cause harm to humans or other living organisms and damage the natural environment. In the San Antonio region, ground-level ozone is our primary kind of air pollution.

Ozone is a gas that occurs both in the Earth's upper atmosphere and at ground level. Ozone can be "good" or "bad" depending on its location. In an upper layer of the atmosphere called the stratosphere, the “ozone layer” is good because it blocks harmful ultraviolet rays. Near the ground, in the air we breathe, ozone is bad because it hurts our lungs and harms other living things.

Ground-level ozone pollution is formed when Nitrogen Oxides (which are found in emissions from vehicles, refineries, and manufacturing or power plants) and Volatile Organic Compounds (which found in gasoline, paint, and cleaning fluids), combine together on hot, sunny days. Because ozone forms during sunny and hot conditions, it is most likely to be a problem during San Antonio’s long, hot summers. Our “ozone season” lasts from March 1 through November 30.

People who are young, who already have breathing problems, or who exercise or work outdoors are harmed the most by ground-level ozone pollution. Symptoms of ozone exposure include coughing, wheezing, pain when taking a deep breath, and breathing difficulties during exercise or outdoor activities. In addition to the respiratory symptoms mentioned above, ozone can inflame airways, aggravate asthma or other respiratory diseases, and increase one’s susceptibility to respiratory infection. Long-term exposure can also accelerate aging of the lungs, diminish lung capacity, and decrease lung function.

When scientists think there will be an unhealthy level of ozone the next day, the government sends out an alert for an Ozone Action Day. On an Ozone Action Day, it is not a good idea to be outside for long periods of time, especially if you are in a more susceptible category. If you would like to receive an email warning of an Ozone Action Day, please contact Lyle Hufstetler at AACOG. 

For more information, visit the U.S. Environmental Protection Agency's Air Now Website.

Reducing Ozone

A large proportion of the ground-level ozone generated in the San Antonio area comes from the exhaust and fumes from vehicles. If we reduce the amount of exhaust and fumes from vehicles, we can reduce the amount of the harmful ozone we have in the air. There are a number of ways we can do this:

Drive less

  • Combine errands into as few trips as possible
  • Consider carpooling (you may find a carpool partner at Alamo Commutes)
  • Use public transportation (check VIA for San Antonio or ART for greater regional areas)
  • Walk or take a bike

Conserve fuel

  • Avoid aggressive driving: start and stop gradually
  • Drive the posted speed limit or less
  • Avoid drive-thru lanes: go inside instead
  • Shut off the engine while waiting outside of schools, businesses, and so on
  • Keep excess weight out of your vehicle
  • Don’t continue to fill your gas tank after the pump has automatically shut off
  • Seal the gas cap tightly: Turn the cap until it clicks three times

Avoid traffic delays

  • Anticipate construction and other congested areas and take alternative routes
  • Leave earlier or later than rush hours to avoid traffic

Also. . . .

  • Keep car engines maintained
  • Keep tires properly inflated
  • Consider buying a “cleaner” or more fuel-efficient vehicle

For more information, contact Lyle Hufstetler at (210) 362-5225 or e-mail.

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