DISCOVER-AQ: Advancing Strategies for Air Quality Observations in the Next Decade

From the Archive—In case you missed's a look back at the September 2014 issue of EM, which included an overview of the NASA DISCOVER-AQ mission.
by James H. Crawford and Kenneth E. Pickering

This month's issue provides an overview of the NASA DISCOVER-AQ mission. As part of this mission, scientists collect pollutant measurements using aircraft, sondes, satellites, and ground-based instruments. These measurements are then used to better understand the processes governing near-surface pollution levels in various urban airsheds with the goal of improving our ability to accurately forecast and mitigate pollutant levels.

Air quality is an environmental condition under constant evolution. Its definition is tied to federal exposure guidelines, but understanding its controlling factors requires detailed knowledge of emissions, chemistry, and meteorology. These factors interact throughout the day to create what can be described as the “chemical weather,” which operates on the same scale as synoptic weather events, but is also infl uenced by the finer spatial and temporal scales associated with patterns of emissions and diurnal meteorological and chemical processes.

Continual and timely characterization of air pollutants in the atmosphere, along with their associated precursors, is critical for successful implementation of the National Ambient Air Quality Standards (NAAQS) and related programs mandated under the U.S. Clean Air Act. This demands an observing system that integrates measurements with computer models to assess exposure for populations and ecosystems to poor air quality,
as well as predict responses to mitigation strategies for consideration by policy-makers.

Over the decades, air quality agencies have largely relied on a combination of in-situ measurements, engineering calculations, and air quality models to provide the quality and quantity of data to characterize air quality in support of air quality management and policy decision-making activities. While satellites can now measure key pollutants (or surrogates) in the atmosphere, such as nitrogen dioxide, sulfur dioxide, ammonia, ozone, formaldehyde, and a variety of aerosol optical properties, such as aerosol optical depth and extinction related to particulate matter, methods are needed to characterize the satellite data so it can be used to derive a relevant air quality metric. ...

Read the full September 2014 issue of EM.