DISCOVER-AQ Mission Improves Air Quality Monitoring

EarthzineArticles, Climate, Original, Sections, Themed Articles, Urban Monitoring Theme

Photo showing a bunch of hands holding up the earth. Photo: Gandee Vasan/Getty Images

Picture of pilots Mike Singer and Shane Dover standing in front of the P-3B NASA aircraft at BWI. Image Source: NASA

Pilots Mike Singer and Shane Dover standing in front of the P-3B NASA aircraft at BWI. Image Source: NASA

The Earth-observing community came together to organize a project called DISCOVER-AQ. The project took place in July 2011, collecting air quality and pollution samples over Maryland using three NASA-built aircraft. DISCOVER-AQ is a four-year campaign, with a mission to improve satellites to monitor air quality for public health and environmental benefits.

DISCOVER-AQ uses aircraft in order to differentiate between air quality at ground level and higher levels. The mission focuses on ozone and particulate pollutants, but also monitors nitrogen dioxide and formaldehyde.

The first aircraft used in DISCOVER-AQ was a 117-foot-long, four-engine turboprop called P-3B Orion, which mainly surveyed low-altitude pollution levels on major highways. It flew 15,000-1,000 feet above the ground in a corkscrew motion to pick up air samples from various altitudes. The P-3B Orion also monitored nitrogen dioxide released by combustion engines on highways. A smaller, two-engine UC-12 flew about 26,000 feet above ground to attain higher altitude air samples. A Cessna operated by the University of Maryland also participated in the project.

These aircraft flew 12-14 times in July. The mission was especially important because there are large discrepancies between the satellite- and ground-based measurements of air pollution.

For example, although there may be a ‰ÛÏcode red‰Û in effect for a particular area, describing extremely high levels of ozone and poor air quality near the ground, conditions could be different at higher altitudes. For instance, data gathered from the NASA’s Aura satellite in 2004 on air pollution was 30%-50% different than the data gathered by ground-based instruments.

‰ÛÏAchieving better measurements of the column at a variety of altitudes is critical to connecting what’s happening at the surface to what we’re seeing from above with satellites,‰Û Scott Janz, a scientist based at Goddard Space Flight Center in Greenbelt, Maryland, said in a NASA article.

The information gathered from the DISCOVER-AQ aircrafts will be used to improve satellite measurements and establish criteria for satellites that monitor air

A map of the P-3B flight path. Image Source: NASA

A map of the P-3B flight path. Image Source: NASA

University of Maryland, Baltimore County and Howard University researchers were among those who used lasers through a technique called Light Detection and Ranging (LIDAR) to make vertical profiles of pollutants in the atmosphere. By using LIDAR measurements on the ground at the same time as aircraft and satellites make their measurements, NASA can more accurately collect air sample data and avoid discrepancies.

‰ÛÏWe’re trying fill the knowledge gap that severely limits our ability to monitor air pollution with satellites,‰Û James Crawford, the campaign’s principal investigator and a scientist based at NASA’s Langley Research Center in Hampton, Virginia, tells NASA.

Dr. Belay Demoz, an associate professor at Howard University, stresses the importance of the project’s education factor. By collaborating with NASA on DISCOVER-AQ, students and interns have the opportunity to learn about quantifying air pollution.

Dr. Demoz tells Earthzine: ‰ÛÏBy getting a better look at pollution samples and the measurement quality, the design of future satellites can be improved. My interest is in how we use all the networking with all the scientists involved in the project and then give students exposure to interpreting data and building satellites.‰Û