Invenio 2009

Creating a model for cleaner air

Air Quality lab

Reducing air pollution is one of the most pressing public policy challenges facing Texas. Failure to meet federal air quality mandates will result in significant public health consequences and hundreds of billions of dollars in lost economic development. Identifying the most effective and efficient approaches to improving air quality requires a sound understanding of the emissions and atmospheric processes that lead to air pollution.

Lamar University's Aldredge Air Quality Modeling Laboratory (AAQML) provides science-based tools for understanding atmospheric chemistry and is able to simulate air pollution scenarios for evaluating control implementation to assist federal, state and local governments in managing air quality problems.

Decades of air quality research, in Texas and elsewhere, have dramatically improved understanding of the local factors that control air quality in urban areas. Increasingly, however, air quality is influenced by more than just local emissions. Regional, continental and even global factors are now known to have a significant influence on air quality in Texas. Identifying the most effective and efficient balance between local, regional and national air quality improvement actions requires a new body of scientific knowledge. In response to this challenge, researchers from universities, state and federal agencies, private industry, and local governments have joined forces to address air quality issues in Texas.

The Aldredge Laboratory has expertise in the two most comprehensive air quality models, the EPA Community Multi-scale Air Quality (CMAQ) and Environ Comprehensive Air Quality Model with Extensions (CAMx). Both modeling systems perform 3-D gridded air quality simulations involving meteorology, emission inventory and atmospheric dynamic processes. By developing expertise in CMAQ/CAMx air quality modeling, the center is able to assimilate field measurements for improving model accuracy.

Under the leadership of Regents’ Professor Thomas "T.C." Ho, the center has become a nationally recognized participant in air quality modeling.

Ho, who joined the Lamar faculty in 1982, has done research in many areas, including waste management, waste incineration, air toxin emission control and coal combustion. He is director of the Gulf Coast Hazardous Substance Research Center at Lamar and holds the Michael E. and Patricia P. Aldredge Endowed Chair in Engineering. A registered professional engineer, Ho holds both a Ph.D. and master's degree in chemical engineering from Kansas State University. His bachelor's degree is from the University of Taiwan.

It is perhaps his cutting-edge work in air quality modeling that will most directly affect Texans. That research is not only addressing the air quality challenges in Texas, but also has taken Ho and colleagues around the globe to address China's growing air quality problems as well. Lamar researchers have made several trips to China to conduct workshops and studies to help the country address its complex air quality problems.

Lamar’s growing expertise in using CMAQ was evidenced when the software, developed in 1997, was updated in 2006 and included an adjustment variable for mercury based on LU research. Because of its toxic and bioaccumulative properties, mercury has been a pollutant of concern for decades. Emission from coal-fired power plants is a primary source of mercury pollution that may enter aquatic systems, become magnified up the aquatic food chain and ultimately harm animals and humans.

Lamar’s state-of-the-art computer models simulate the meteorological conditions and chemical reactions that contribute to the formation of air pollutants such as ground-level ozone, the most prevalent air pollution in Texas and the nation. The computer models help the TCEQ estimate future air quality in Texas communities that have ozone problems and assist agency staff in designing appropriate air-pollution controls.

Caused primarily by emissions from internal combustion engines, chemical plants and power plants, ozone is an unstable and highly reactive molecule of three oxygen atoms bound together. Ozone irritates the respiratory system, reduces lung function and aggravates asthma and other chronic lung diseases.

Computer models predict how air quality in a region will be affected by economic and population growth and by emissions reductions resulting from federal, state and local programs. Like all models of complex physical systems, the models used by the TCEQ have some uncertainties, but EPA recognizes these models as the best tools available for developing plans to achieve clean air goals.

The models examine emissions, meteorological and photochemical processes, and their interactions. The Federal Clean Air Act (FCAA) requires each state to maintain a state implementation plan (SIP) which "provides for implementation, maintenance, and enforcement" of the National Ambient Air Quality Standards (NAAQS), for specified air contaminants, including ozone, particulate matter and regional haze. Because some areas in Texas do not comply with the NAAQS for ozone, the state has amended the Texas SIP to include plans for attaining the standards in each of these areas. The FCAA requires most areas that fail to comply with the standards to use photochemical grid models to demonstrate that the standards will be attained by dates specified in the Act. The EPA may also require states to include plans for addressing regional air quality issues (such as regional haze caused by particulate matter) in their SIPs.

Texas ozone nonattainment areas are Beaumont-Port Arthur (attainment date 2008), Dallas-Fort Worth (attainment 2010), Houston-Galveston-Brazoria (attainment 2018) and San Antonio (deferred). To address the requirements of the Clean Air Act, TCEQ has made substantial investment in the air quality modeling program at Lamar University, including funds to create a "clean" room to house expanded computer labs and to purchase additional computers to run the highly complex simulations.

The Aldredge Laboratory in the College of Engineering at Lamar University is a newly established workspace designated for intensive air quality simulations. Housed in the Cherry Engineering Building, the laboratory has a number of high-performance computing platforms and network-attached storage for the proposed modeling work and data storage/archiving for data sharing. The primary AQML hardware facilities include two DELL PowerEdge Linux clusters with 120 CPUs for parallel computing, one Dell PowerVault rack-mount NAS server for storage management, one Sun L-9 tape autoloader for data backup and archiving, 4 PCs for document preparation and data analysis, and two high-speed, network-attached color LaserJet printers.

The AQML software capabilities include dynamic meteorological simulations (MM5), emission inventory processing (SMOKE and EPS-2) and a number of first-principle chemical transport models, including the USEPA Community Multi-Scale Air Quality Modeling (CMAQ) system, Comprehensive Air-quality Models with Extension (CAMx) and the Sulfur Transport Eulerian Model (STEM). There are also a number of utility programs to support the data I/O and conversion, as well as the software to conduct statistical treatment and data visualization.

Directing the center are five Lamar faculty members, supported by two research associates and as many as eight students working in the laboratory.