Ten-Year Endeavor: NASA’s Aura Satellite Tracks Pollutants

Ten-Year Endeavor: NASA’s Aura Satellite Tracks Pollutants NASA’s Aura satellite, celebrating its 10th anniversary this year on July 15, has provided vital data about the cause, concentrations and impact of major air pollutants. With its four instruments measuring various gas concentrations, Aura gives a comprehensive view of one of the most important parts of Earth — the atmosphere.

When astronaut William Anders flew on the first manned mission to orbit the moon in 1968, he photographed the surreal view of Earth rising above the lunar horizon. “We came all this way to explore the moon, and the most important thing is that we discovered the Earth,” Anders famously said. Back on the planet though, problems were brewing in the atmosphere.

Exhaust from cars and pollutants like sulfur from power plants masked the sky. In large cities, air pollution caused some people to experience burning in their lungs and eyes. Acid rain contaminated fresh water sources and damaged plant life. Earth’s atmosphere was experiencing chemical chaos, but scientists didn’t necessarily know the extent or have a detailed explanation. Nevertheless, the U.S. government introduced the 1970 Clean Air Act to reduce some of the pollutants and chemical chaos.

Since then, decades of satellite-based observations have helped researchers understand the chemical processes in the atmosphere that affect human lives in the short-term and long-term.

The atmosphere begins at the ground level where people live and breathe. Air pollution can be seen as a smoky haze lingering in the sky and blocking the sun’s light. As early as the 1940s, Los Angeles would shut down for days as large masses of toxic smog filled the sky and burned people’s throats and eyes. At the time, the cause and long-term effects of the noxious clouds were not well understood.

Today, scientists know that this Los Angeles pollution was different from the sulfur-laden smog of coal towns. This modern smog contained ozone – a pollutant that is not emitted from tailpipes or smoke stacks but is formed through chemical reactions in the sunlit atmosphere. While ground-level ozone is not presently measured by any space-based instrument, the Aura satellite can measure nitrogen dioxide, which is a key ingredient to the formation of ozone.