New Insights in Air Quality Monitoring Using Satellite Data

• By: AWMA
• On: 09/09/2021 13:59:58
• In: EM Articles
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by James Cascione

The field of remote sensing began with the advent of aerial photography where early pioneers recognized the potential to collect information about the Earth's surface and society's impact on the landscape from the unique perspective afforded at high altitudes. Today, scientists deploy increasingly sophisticated sensor technology on orbital platforms that gather data on ever-finer spatial and temporal resolutions, while covering large geographic swaths of the planet. These instruments include both passive spectrometers that detect reflected or re-transmitted solar radiation, as well as active laser-based systems that emit electromagnetic radiation and detect the reflected energy.

In either system, the orbiting sensors are collecting the response signal, a unique spectral signature of electromagnetic energy interacting with the object or phenomena understudy. Combined with varying methods to process the collected signal response, satellite instruments can provide measurements of several air pollutants at ground level and throughout the layers of the Earth's atmosphere. To this end, the field of remote sensing has provided air quality managers and policy-makers an ever-expanding set of data to chronicle the source, transport, and fate of air pollutants on regional and global scales.

In this issue, we present five articles wherein authors describe the insights that recent and future satellite missions will contribute to our understanding of atmospheric pollutants and how that information can be accessed and used to support future decisions on air quality management.

The first article, by Drs. Tracey Holloway and Jennifer Bratburd, provides a background of how satellite technology is employed to measure air pollutants and provides examples of the types of data available from these instrument systems.
 
Next, Dr. Ana Prados and colleagues discuss an overview of current satellite instruments measuring several U.S. criteria air pollutants—carbon monoxide (CO), nitrogen dioxide (NO₂), ozone (O₃), particulate matter (PM_2.5 and PM₁₀), and sulfur dioxide (SO₂)—providing examples of their use in characterizing the impacts from the 2020 wildfires that affected the western United States.
 
Then, Dr. Daniel Goldberg and colleagues present recent analysis of NO₂ emission data from the 2017 launch of the passive spectrometer Tropospheric Monitoring Instrument (TROPOMI) aboard the European Union's Copernicus Sentinel 5 Precursor (S5p) satellite.
 
The fourth article, by Dr. Aaron Naeger and colleagues, discusses the planned launch of NASA's Tropospheric Emissions: Monitoring of Pollution (TEMPO) instrument, which will provide measurements of several organic and U.S. criteria air pollutants at and near ground level (i.e., within the 0–2-kilometer layer of air) within North America.
 
Finally, Dr. Susan Anenberg and colleagues discuss how satellite data is being utilized in the investigation of neighborhood-scale air pollution inequalities that form the basis of environmental justice (EJ) policies enacted at state and federal levels.

Continue reading the full September 2021 issue of EM.