Exposure Research
EPA scientists collaborate with NASA to improve view of air pollution from space
Posted: January 30, 2013
EPA exposure scientists are collaborating with NASA on a multiyear study to help scientists better understand how to measure and forecast air quality globally from space. The NASA-led mission — known as “DISCOVER-AQ” — stands for Deriving Information on Surface conditions from COlumn and VERtically resolved observations relevant to Air Quality.
This second of four DISCOVER-AQ field missions began in January 2013 and will continue through February 2013. Two NASA aircraft equipped with scientific instruments are making daily flights over California’s San Joaquin Valley between Bakersfield and Fresno to measure air pollution.
During the DISCOVER-AQ study, researchers are working to improve the ability of satellites to consistently observe air quality in the lowest part of the atmosphere. This could lead to better air quality forecasts and more accurate determinations of where pollution is coming from and why emissions vary. Because many countries, including the United States, have large gaps in ground-based networks of air pollution monitors, experts look to satellites to provide a more complete geographic perspective on the distribution of pollutants.
Gathering pollutant data via satellite, plane, and ground-based instruments
A challenge for space-based instruments monitoring air quality is to distinguish between pollution high in the atmosphere and pollution near the surface where people live. To address this issue, DISCOVER-AQ is employing NASA aircraft to make a series of flights equipped with air monitoring devices to simulate existing satellite instruments. The data collected will be compared to data being gathered at ground-based monitoring sites, as well as data from a fleet of NASA-operated satellites that will pass daily over the DISCOVER-AQ study area.
During the five-year study, airplane flights will occur in four locations — Baltimore, Md.; San Joaquin Valley, Calif.; Houston, Texas; and Denver, Colo. During the missions, different air pollutants, unique to each city’s location, will be monitored. EPA scientists will provide equipment and expertise for measuring pollutants at ground-based monitoring sites.
Multiple daily flights are underway at the current location in the San Joaquin Valley. During each flight, one plane is flying at approximately 26,000-feet using remote sensing technology to sample a column of air beneath it. A second plane is flying at approximately 1,000 feet sampling the surrounding air. This plane is also making spiral flights over six surface air quality monitoring sites operated by the San Joaquin Valley Pollution Control District and the California Air Resources Board. EPA scientists are stationed at three of these sites where they have installed and are operating equipment to measure nitrogen dioxide.
Evaluating state-of-the science methods for measuring air pollution
The ground-based instruments operated by EPA will complement ground data being gathered by other DISCOVER-AQ collaborators. Throughout this mission, EPA scientists are evaluating new, state-of-the-science methods for measuring nitrogen dioxide. One of the three sites operated by EPA is located next to a highway, allowing scientists to gather traffic-related air quality data. The near road site will also allow EPA scientists to test new Federal Reference Methods and Federal Equivalent Methods for measuring nitrogen dioxide and other pollutants.
The San Joaquin Valley mission follows the first of the DISCOVER-AQ missions which took place in Baltimore during July 2011. During the Baltimore study, EPA provided key ground-based measurements at multiple sites for both ozone and nitrogen dioxide. Upon completion of the Baltimore fieldwork, EPA scientists have been helping develop and evaluate new ground-based methods to measure ozone and nitrogen dioxide. Among these are sensor-based technologies for measuring ozone and nitrogen dioxide.
The EPA-NASA collaboration will continue in 2013 with a third field mission in Houston during late summer or early fall. During this field research, EPA scientists will be testing new compact sensor technologies for measuring ozone and nitrogen dioxide at the earth’s surface. The Houston mission will allow EPA scientists to compare compact sensor-based methods to more traditional methods currently used to monitor air quality. The fourth and final mission is scheduled for summer 2014 in Denver.
More EPA-NASA collaboration
EPA exposure scientists expect to use the DISCOVER-AQ data they collect in the four field studies to help plan for their participation in a newly selected NASA satellite mission called TEMPO, or Troposheric Emissions: Monitoring of Pollution, expected to launch in 2017.
The TEMPO project involves building the first space-based instrument to monitor major air pollutants across the North American continent hourly during daytime. The instrument, to be completed by September 2017, will share a ride on a commercial satellite that will orbit about 22,000 miles above Earth’s equator. Current methods utilize satellites orbiting much closer to the earth’s surface, allowing for observations of atmospheric pollutants to be made only once a day.
Led by the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., TEMPO will make the first measurements of tropospheric pollution over North America. The space-based instrument will be able to measure trace concentrations of ozone, nitrogen dioxide, sulfur dioxide, formaldehyde, and aerosols with high frequency and resolution.
In addition to EPA, the TEMPO team will include partnerships with Ball Aerospace and Technologies Corp. in Boulder, Colo.; NASA’s Langley Research Center in Hampton, Va.; NASA’s Goddard Space Flight Center in Greenbelt, Md.; and several U.S. universities and research organizations.
More on DISCOVER-AQ:
- Major NASA air pollution study to fly over California
- DISCOVER-AQ mission highlights
- Listen to NPR story on 2011 Discover-AQ field study in Baltimore-Washington area
More on TEMPO: