Air Quality

For today’s air quality forecast click here:

Why is our air so bad?
The San Joaquin Valley Air Basin is approximately 250 miles long and is shaped like a narrow bowl. The sides and southern boundary of the “bowl” are bordered by mountain ranges. The Valley’s weather conditions include frequent temperature inversions, long, hot summers, and stagnant, foggy winters, all of which are conducive to the formation and retention of air pollutants.

The bowl-shaped Valley collects and holds emissions caused by the activities of the Valley’s three million residents and their two million vehicles, as well as vehicles from other areas traveling on Highway 99 and Interstate 5. In addition, pollutants are also transported into the Valley from the Bay Area and the Sacramento Valley. These characteristics cause the San Joaquin Valley to be unusually susceptible to significant air pollution problems.

How much comes from other areas?
Air pollution transported from the San Francisco Bay and Sacramento areas account for approximately 27% of the total emissions in the Northern portion of the District (San Joaquin, Stanislaus, and Merced Counties). In the Central region (Fresno, Madera and Kings Counties), the percentage drops to 11%, and in the south valley (the Valley portion of Kern and Tulare Counties), transported air pollution accounts for only 7% of the total problem.

While some of our pollution is blown in from other areas, most of our air pollution is home grown and it is our responsibility to clean it up.

What causes air pollution?
“Mobile sources” include light, medium and heavy-duty vehicles and motorcycles. Non-road mobile sources include construction equipment, farm tractors, trains, ships, aircraft, mobile equipment, and utility equipment such as lawn mowers and chain saws.  “Stationary sources” include industrial facilities, stores such as gas stations and dry cleaners.  “Area sources” include consumer products (for example, deodorants, and nail polish), house paints, pesticides, agricultural burning, and small commercial sources such as gas stations and dry cleaners.  “PM10 sources” generally fall into two categories: human (anthropogenic) activity and natural sources (nonanthropogenic). Anthropogenic sources include agricultural operations, industrial processes, combustion of wood or fossil fuels, earthmoving activities, and entrainment of road dust into the air. Nonanthropogenic sources include windblown dust and wildfires.

What health problems does air pollution cause? 
Often invisible, but harmful, air pollution threatens the health and well being of all living creatures. Some health effects of smog and other types of air pollution include:

  • Irritation of mucous membranes
  • Coughing and wheezing
  • Chest pain and tightness
  • Dry throat
  • Headache
  • Nausea
  • Fatigue

Air pollutants such as ground-level ozone and particulate matter can aggravate chronic respiratory diseases such as asthma and bronchitis. When exposed to high levels, people may experience shortness of breath, pain during deep breaths, and impaired lung function.

What does TCAG do about air quality?  
TCAG educates the public regarding air quality issues via public outreach campaigns.  TCAG also alleviates air quality issues by preventing and alleviating congestion on our roadways, expanding public transit by improving and expanding existing infrastructure and optimizing routes, and promoting active transit such as walking or biking by improving upon and creating new bicycle paths.

Congestion Mitigation & Air Quality (CMAQ)

Program Funding
The purpose of the Congestion Mitigation and Air Quality (CMAQ) program is to fund transportation projects or programs that will contribute to meeting national ambient air quality standards by relieving congestion and improving air quality. Tulare County receives approximately $4.5 million a year in CMAQ funds.

Call for Projects
About every two years, TCAG announces a call for projects for CMAQ funds. During this time, member agencies are given the opportunity to submit projects that they would like to receive CMAQ funding. The last two calls for projects were released in September 2009 and January 2011.

TCAG has approved CMAQ policies regarding how projects are selected and how those funds will be allocated. Cost effective projects shown to be the most successful at improving air quality are typically given funding priority.
Contact Information
For additional information on the CMAQ program, please contact TCAG by calling (559) 623-0450.

Posts and Documents