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8th-Background Information for Teachers: Attainment and Thermal Inversions

Eighth graders should explore the conflicts between those who produce pollutants and the organisms that are exposed to them.

The following information is from

Texas has had a tenuous relationship with the Environmental Protection Agency (EPA). Texas legislators and business owners have refused EPA monitoring of greenhouse gas emissions and air permit requirements in the state. Reasons for this vary and include claims of states' rights and rejection of EPA rulings on the dangers of six greenhouse gases. In May 2011, the Texas House passed a measure asking federal legislators to prevent the EPA from regulating emissions in the state under the Clean Air Act. The state lost similar legal battles in 2010 and 2011.

EPA detractors note that the agency's standards could threaten Texas jobs if stricter measures put older coal plants out of business. The Electric Reliability Council of Texas (ERCOT) says the regulations could be too costly for older plants to accommodate, adding that it would take time to retrofit or replace plants that do not meet the standards. The gap could threaten the state's ability to produce sufficient electricity to maintain power in the state during emergencies such as the 2011 rolling blackouts that left millions of Texas temporarily without power.

EPA standards are in flux, and changes could push Central Texas into the "non-attainment" zone, meaning it doesn't meet regulations. That could hurt Texans by way of lost federal funding for environmental programs. The EPA faces budget challenges after federal cuts that may limit its ability to regulate carbon emissions throughout the country, Texas included.

The following information on Temperature Inversions is from Both Sides of the Border: Transboundary Environmental Management Issues Facing Mexico and the United States by Linda Fernandez, Richard T. Carson. Sage Publications, 2003, p. 259.

Normally air temperature decreases with altitude. The inversion of this process is called thermal inversion. Most thermal inversions occur in the winter months. Information gathered in the El Paso area indicates the thermal inversions in the Paso del Norte region occur in the fall and winter, starting in September when the nights become longer. However, they are more frequent in November, December, and January when nights are longer and days are shorter. In December, for example, the nights are approximately 14 hours, while the days are 10 yours (Texas Air Control Board, 1991).

Additionally, during this time of the year, the desert presents a bit of humidity, favoring strong cooling when there are clear skies. The air close to the ground is cooled more quickly than the air in high atmospheric layers, which causes a nocturnal thermal inversion that traps the pollutants emitted in the basin. These inversions tend to be shallow, thus reducing the volume available for the vertical mixing and dispersion. This causes high concentrations of pollutants near the surface. During the morning, strong local heating begins to break the inversion and by the afternoon, the usually unstable atmosphere makes it favorable for the pollutants to dissolve in the high atmosphere.

Characterization of Traffic Related Air Pollution in Elementary Schools and its Impact on Asthmatic Children in El Paso, Texas

Authors: Li, When-Whai, Sarnat, J.A., Rayson, A.U., Sarnat, S.E., Stock, T.H., Holguin, F., Greenwald, R., Olvera, H.A., Johnson, B.A. National Urban Air Toxin Research Center Research Report, No. 20, 2011.

According to the U.S. Department of Transportation, 15 – 16 million passenger cars and 750,000 commercial vehicles cross the four ports of entry between El Paso and Ciudad Juárez each year. Traffic-related pollutants concentrate within 100 meters of busy roads. Many schools are in these traffic zones.

This study investigated the air quality and children's health in four schools in the El Paso Independent School District. Three schools were located near Ascarate Park and close to Interstate 10, the Border Highway, and the international bridges. One school is particularly close to an oil refinery. In 2009, a different study found that two of these schools were among the most polluted schools in the nation. The fourth school was located near the mountain in an area where there is healthier air flow and fewer sources of pollution.

The purpose of the study was to identify pollutants that were in the air at the four schools and to find information from indicators of the students' health that might be related to air pollution. The results show that the air pollution levels at the three schools near the pollution sources were higher than pollution levels at the school in the clean air zone and often higher than recommended by the national air quality standards. Children at these schools exhaled higher levels of nitric oxide than children at the school in the clean air zone. Higher levels of nitric oxide is an indicator of inflammation in the lungs which is a characteristic of asthma. All of the air quality monitors at the schools reported high levels of course particulate matter (PM10-2.5).

Earlier studies have found that air pollution is related to respiratory problems for children who are exposed to the pollution. Here is what those studies found.

  • Increases in hourly ozone levels of 20 ppb were associated with an increase (5.1%) in respiratory-related emergency department visits for children in in Ciudad Juárez.
  • Increases in particulate matter concentrations in the air was related to a 20% increase in asthma-related emergency department visits for children in El Paso.
  • Children in Ciudad Juárez had more lung inflammation (using the test of exhaled nitric oxide) when there was a higher concentration of traffic-related nitrogen dioxide (NO2) in the air.
  • Children who live along the Texas-Mexico border are hospitalized for asthma at a 36% higher rate than children who do not live in this border area (Grineski, 2007).

This 2011 study found that the three schools in the high pollution zones:

  • Had higher levels of volatile organic compounds – chemicals that result from burning gasoline in cars, trucks, airplanes, etc.
  • During the times when the studied measured higher levels of air pollutants, they found higher airway inflammation and problems with lung function for children with asthma. The higher levels of volatile organic compounds caused the strongest observed effects.
  • Pollutants levels for indoor and outdoor air quality were often similar. Activities such as painting, cooking with natural gas, art projects with glue, etc. increased the pollution levels indoors.

8th Introduction

8th Background Information

8th Inquiry Activities