NASA’s Aura satellite, celebrating its 10th anniversary on July 15, has provided vital data about the cause, concentrations and impact of major air pollutants.
Aura has improved our understanding of ozone, a gas. Near the ground, ozone is a pollutant that damages plants and can decrease lung function in humans. Most ozone, about 90 percent, is high in the stratosphere, where it shields the Earth from the sun’s ultraviolet light and makes life possible.
Over the Antarctic, cold temperatures and human-produced chlorine gases destroy ozone each spring. Aura revealed two of the largest and deepest ozone holes in the past decade (above), and helped scientists understand the different causes of the two large holes.
Aura also monitors levels of another major pollutant: nitrogen dioxide. This brownish gas can lead to respiratory problems and is an ingredient in ground-level ozone pollution. Aura saw that nitrogen dioxide levels in the United States decreased 4 percent per year from 2005 to 2010, a time when stricter policies on power plant and vehicle emissions came into effect. During the same period, global nitrogen dioxide levels increased a little over half a percent per year. China’s level increased about 6 percent per year.
The European Space Agency will be launching the follow-up TROPOspheric Monitoring Instrument, which will continue Aura’s measurements with better ground resolution and precision. NASA plans to launch the Tropospheric Emissions: Monitoring of Pollution (TEMPO) instrument, which will observe ozone, nitrogen dioxide, sulfur dioxide, formaldehyde and aerosols over the United States, Canada and Mexico.