By Land, Air, Sea and Satellite, NOAA Seeks Improved Air Quality and It Links to Climate

During the 2000 Texas air quality field study (TexAQS2000), NOAA scientists discovered a major factor that causes the Houston area to experience the highest ozone levels in the United States. Revisions made to the state's air quality management plan based on the 2000 results are expected to save Texas $10B and 65,000 jobs by the year 2010.

NOAA returns to Texas this year to extend this research and improve our understanding of the links between air quality and climate.

Pollution haze obscures the downtown Houston skyline.

Photo: University of Texas.

Pollution haze obscures the downtown Houston skyline.

This summer in Texas, researchers in two NOAA-led field studies in East Texas and the northwestern Gulf of Mexico are investigating important scientific questions that are common to both air quality and climate. Through the Texas Air Quality Study and Gulf of Mexico Atmospheric Composition and Climate Study (TexAQS and GoMACCs), the scientists expect to improve understanding of the chemical and meteorological processes that control atmospheric levels of air pollutants, greenhouse gases, and airborne particles, called aerosols.

Led by NOAA's Earth System Research Laboratory (ESRL), the Texas Commission on Environmental Quality (TCEQ), and the University of Texas, the two summer field missions are bringing together researchers from federal agencies, universities, and private industry. Three other NOAA research laboratories, the Pacific Marine Environmental Laboratory, Atlantic Oceanographic and Meteorological Laboratory, and Air Resources Laboratory are also participating. Staff in ESRL's Chemical Sciences Division are taking a lead role in the two experiments and are providing important instrumentation. and severe weather forecasting.

Through a large array of research instruments on the ground, at sea (on R/V Ronald H. Brown), in the air (including two NOAA aircraft), and on satellites, researchers are gathering observations that will lead to a better understanding of the sources and atmospheric processes responsible for the formation and distribution of ozone and aerosols in the atmosphere. The data will shed light on how these species influence the radiative properties of climate regionally and globally and how they impact human health and regional haze.

The Climate Change Focus

GoMACCS, the NOAA climate change component of this field program, will characterize marine and continental chemical and meteorological processes over Texas and the Gulf of Mexico to improve computer models of the radiative forcing of climate change by lower-atmosphere ozone and aerosols. GoMACCS will investigate clear-sky radiative effects, the influence of aerosols on cloud properties, and the role that clouds play in chemical transformation.

The Air Quality Focus

TexAQS, the NOAA air quality component of the field experiment, will investigate the sources and processes responsible for photochemical pollution and regional haze during the Texas summer. Several Texas counties are experiencing severe to moderate air quality problems associated with this ozone. Other counties in the state soon may be facing similar issues. The 2006 mission will provide information on the sources of the ozone and aerosol precursors, as well as the processes responsible for the formation and distribution of ozone and aerosols in the state.

A major air quality focus of the mission is the transport of ozone and ozone precursors within the state and the impact of the long-range transport of ozone or its precursors into, and perhaps out of, the state. Researchers are paying special attention to nighttime chemistry and transport. The study is also investigating how the various urban, industrial, and natural sources of aerosols and aerosol precursors within the state and the transport of aerosols from outside the state contribute to the regional haze.

The NOAA Research Platforms

NOAA R/V Ronald H. Brown is an ideal platform for studying the meteorological and chemical processes occurring off the coast of Texas and along the Houston Ship Channel and Galveston Bay. Instruments onboard, including those on the scaffolding tower, will sample polluted air masses as they move on- or offshore. The data will help scientists understand chemical transformations in the polluted marine boundary layer. Shipboard sampling provides a unique opportunity to characterize the complex interactions that influence pollution distributions along the coast.

NOAA R/V Ronald H. Brown departs from Portsmouth, New Hampshire, July of 2004, during the New England Air Quality Study.

Photo: Steven Brown, NOAA

NOAA R/V Ronald H. Brown departs from Portsmouth, New Hampshire, July of 2004, during the New England Air Quality Study.

The NOAA WP-3D Lockheed Orion aircraft has been outfitted as a flying chemical/meteorological laboratory. The plane will sample both daytime and nighttime chemistry and meteorology. The measurements are important for addressing the processes of ozone and secondary aerosol formation and the roles played by emissions, chemistry, and transport in shaping Texas air quality.

NOAA WP-3D Lockheed Orion aircraft.

Photo: NOAA Aircraft Operations Center

NOAA WP-3D Lockheed Orion aircraft.

In addition, the WP-3D will systematically study the formation and evolution of the chemical and optical properties of aerosols from urban and industrial sources. These measurements will address primary GoMACCS climate questions: How do various types of emissions and their subsequent atmospheric chemistry determine the optical properties of aerosols? Ultimately, how do aerosols affect radiative forcing in the atmosphere?

NOAA's Twin Otter aircraft with an airborne ozone/aerosol differential absorption LIDAR (DIAL) instrument onboard.

Photo: Scott Sandberg, NOAA

NOAA's Twin Otter aircraft with an airborne ozone/aerosol differential absorption LIDAR (DIAL) instrument onboard. A LIDAR is a laser radar.

The field mission will greatly benefit from the deployment of an ozone/aerosol lidar, or laser radar, onboard NOAA's Twin Otter aircraft. The lidar will measure regional ozone and aerosol distribution so that scientists can characterize the three-dimensional structure of pollution plumes and measure variability in mixing-layer height.

The lidar's remote sensing from the Twin Otter will complement the in-situ observations made on the WP-3D aircraft. By planning several aircraft flight tracks to sample the same region at the same time, researchers will be able to build a three-dimensional representation of the data.

Extending Past Successes

During the 2000 Texas air quality field study (TexAQS2000), NOAA scientists discovered a major and previously unexpected factor that causes the Houston area to experience the highest ozone levels in the United States. Based on NOAA's discovery that leaks of reactive gases from the many petrochemical refineries in the area are a much larger factor in Houston's poor air quality than was previously expected, revisions were made to the state's air quality management plan. The revised strategy, based on the 2000 results, is expected to save Texas $10B and 65,000 jobs by the year 2010, compared to other alternatives.

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