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Clean Air Program

Who We AreBlue Sky with Clouds

The Pima County Department of Environmental Quality's Voluntary No-Drive Day Program (also known as the Clean Air Program) was established in 1989 and is mandated by the omnibus air quality legislation enacted in 1988 (A.R.S. § 49-506) and Pima County Code 17.44.020. In the past, Pima County experienced violations of national air quality standards. To prevent further deterioration, several initiatives were developed to reduce air quality emissions in Pima County. The Clean Air Program/Voluntary No-Drive-Day is one of those initiatives.

The PDEQ Voluntary No-Drive Day/Clean Air Program is also a permanent and enforceable control measure approved into the most recent Carbon Monoxide Limited Maintenance Plan by EPA effective January 20, 2010 [74 FR 67819; 12/21/09]. The principal goals of the Program are to reduce vehicle emissions that contribute to air pollution by increasing public awareness of air quality issues and encouraging alternative modes of transportation and other pollution-reducing activities.

How We Are Funded

The Pima County Clean Air Program is funded by a grant from the Arizona Department of Environmental Quality. In addition, grants from other agencies may help fund the program. No local tax revenue is used to support the Voluntary No-Drive Day/Clean Air Program.

What We Do

As part of our clean air strategy we:

  • Provide information to the public  and the media regarding current air quality conditions, sources of air pollution, and associated health effects.
  • Sponsor community awareness events encouraging citizens to reduce vehicle miles traveled and to use alternate modes of transportation.
  • Provide teacher resources to facilitate student air quality education.
  • Conduct air quality presentations to community groups and students of all ages.
  • Work with other organizations and transportation planners to coordinate efforts towards reduced traffic congestion and improved air quality.

What's In Our Air?

Up-to-the-hour air pollution levels can be obtained from many of Pima County Department of Environmental Quality's (PDEQ) 17 air quality monitoring stations. Check out PDEQ's Air Info Now for current air pollution information.  PDEQ monitors for six air pollutants as required by the Environmental Protection Agency (EPA). These pollutants are:

  • ozone
  • particulate matter
  • nitrogen dioxide
  • sulfur dioxide
  • carbon monoxide
  • and lead.

The levels of air pollutants are categorized using the Air Quality Index as good, moderate, and unhealthful.Particulate Air Pollution Monitor

Nitrogen dioxide, lead, and sulfur dioxide levels consistently fall within the good range. The remaining pollutants often are measured in the moderate range.

The three other pollutants for which Pima County monitors are: carbon monoxide, ozone, and particulate matter. Carbon monoxide is an odorless, colorless, poisonous gas emitted in motor vehicle exhaust. Carbon monoxide levels tend to be higher in the winter because of stagnant air conditions, but are consistently in the "good" range.

Ground-level ozone is formed by the reaction of intense sunlight with motor vehicle exhaust and other pollutants. Ozone levels tend to be higher in the summer when we have more hours of sunlight. We are very close to exceeding the EPA health standard for ozone and could be classified as non-attainment of that standard in the near future if we are not able to reduce emissions that contribute to ground-level ozone.

Particulate matter consists of small particles, such as soot and dust, that come from motor vehicle emissions, tire and brake wear, earth-moving activities, fireplaces, and dust from unpaved surfaces. Particulate matter (PM) levels tend to be high during dry times of the year, especially on windy days. PDEQ monitors for two different sizes of particulates; PM2.5 (particles with an aerodynamic diameter of 2.5 micrometers or less) and PM10 (particles with an aerodynamic diameter of 10 micrometers or less).  In 1999, Pima County exceeded the federal health standard for particulate matter on four days. These four exceedances constitute a violation of the EPA health standard. As a result of these exceedances, PDEQ developed a Natural Events Action Plan to reduce future PM10 exceedances and protect public health.


Facts About Our Air

  • Air pollution affects the health of all of us and causes a loss of lung function.
  • Air pollution contributes to the development of diseases including bronchitis, emphysema and, possibly, cancer.
  • People most at risk from air pollution include those with lung and heart disease, older adults, children, and adults who are active while outside.
  • Up-to-the-hour air pollution levels can be obtained from many of Pima County Department of Environmental Quality's air quality monitors. Check out Air Info Now for current air pollution information.
  • About 50 percent of our air pollution in Pima County is caused by motor vehicle use.
  • Tucsonans drive over 23,000,000 miles every day! (That's over 80 trips to the moon.)
  • Every 31 miles we drive puts one pound of pollution into the air.
  • Checking your tires once a month and keeping them properly inflated will help you save money, reduce your trips to the gas station and keep your tires lasting longer.  
  • You're the solution to air pollution.

By driving less and reducing energy use, you can help keep Pima County a healthy community. Clean air is up to you.

What's at Risk?

Our Health is at Risk When Air Quality is Poor

Air pollution is a serious threat to human health. Those especially at risk include children, older adults, pregnant women, outdoor workers and exercisers, and individuals with lung and heart ailments. The long-term exposure to moderate levels of air pollution can damage even healthy people's lungs. In Pima County, we are fortunate that our air quality is good on the majority of days, however, there are times when air pollution levels can cause health problems for those at risk.Outdoor Exerciser with Dog

Our Economy is also at Risk

Air pollution is also bad for our economy. The costs of air pollution include health care expenses, lost work due to illness, and damage to agricultural crops, buildings, paint, and rubber. Air pollution can also affect tourism and the ability of businesses and institutions to recruit quality employees. By following the suggestions on the "What Can You Do?" tab, we can keep our community physically and economically healthy for future generations.

What Can You Do?

There are many actions we can take to keep our air healthy to breathe.  Motor vehicles are Pima County's largest source of air pollution, and most vehicles are driven by motorists traveling alone. If enough people chose not to drive alone once or twice a week, our air pollution levels would decrease considerably.

  • Join a carpool. Plan one day a week to meet a carpool at the corner, the day care center, or at a nearby Park and Ride lot. Call (520) 884-RIDE  or visit Sun Rideshare for free Bicycle with basket and flowersinformation on how to start a carpool.
  • Bicycle or walk to nearby destinations whenever possible. Check out local bike paths and The Loop for routes you can try.
  • You can save $1,000 a year by riding Sun Tran! Catch it at the corner, or drive to a Park & Ride lot. Contact Sun Tran at (520) 792-9222 or Sun Tran's website for the bus schedule, trip planning or other information.
  • Combine your errands into one trip to "skip a trip" whenever possible. A cold engine decreases efficiency by as much as 80 percent.
  • Some people have to travel alone. If you do, here are some things you can do to minimize your vehicle's polluting emissions:
    • Keep your air filter clean and get regular tune-ups. A neglected car can reduce gas mileage by 20 percent.
    • Make sure your tires are properly inflated. You can save $400 a year in gasoline costs!
    • Trade your car in for a newer model. Newer cars are more efficient and pollute less.
    • Don't "top off" your gas tank. By stopping at the click, you will reduce fumes that contribute to ozone creation.
    • Avoid idling. In general, turning off and starting an engine uses less gasoline than letting it idle for 30 seconds.

Other actions you can take to reduce air pollution:
  • Talk to your employer about the possibilities of telecommuting or working compressed work weeks.
  • Paint with water-based paints and use brushes or rollers instead of a paint sprayer.
  • If you are barbecuing, use an electric or chimney-type fire starter instead of lighter fluid.
  • Avoid using your fireplace unless it is your sole source for heat. If you like the flicker of flames, consider using multiple candles of varying heights in your firebox, instead of burning wood.
  • Support local clean air initiatives by letting your elected officials know how you feel about air pollution.
  • Conserve electricity. Electrical generation is a source of air pollution.
  • Conserve water. It takes a lot of energy to transport water, and to heat it.
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Department of Environmental Quality

33 N. Stone Ave., Suite 700
Tucson, AZ 85701

Phone: (520) 724-7400
Fax: (520) 838-7432


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