TEMPO, which stands for Tropospheric Emissions: Monitoring Pollution, is the first-ever space-based instrument to monitor air pollutants hourly across the North American continent during daytime.

Recognized by TIME magazine as one of the best inventions of 2023, this National Aeronautics and Space Administration (NASA) instrument tracks pollutants such as nitrogen dioxide, ozone, aerosols, sulfur dioxide, and formaldehyde from sources such as cars, oil refineries, and wildfires in the daytime. At night, it measures light pollution.

It can pinpoint pollution sources in geographic areas as small as 4 square miles. Once the hourly data is processed, it’s made available to the public and scientists.

“TEMPO’s high-resolution data will be archived at and distributed by NASA’s Atmospheric Science Data Center (ASDC). ASDC plans to have validated and processed data available in Spring 2024,” reports EarthData.

The TEMPO mission officially began in 2013 and “cost $210 million, with just over $90 million of that total going to instrument development,” reports The Gazette.

Dozens of researchers created the instrument, which launched into space in April 2023 and projected its first data in August 2023. Full operations commenced in October, The Gazette added.

“TEMPO’s hourly dumps of continental air quality measurements result in mounds of data to verify.”
According to the Fact Sheet, TEMPO will provide data:

• To inform U.S. air quality standards as they continue to become more stringent to better protect human health;
• To monitor and quantify new and transient pollution sources (e.g., vehicular traffic, oil and gas development, trans-boundary pollution), which are growing in importance yet are very difficult to monitor from ground networks; and
• To monitor many areas that aren’t currently monitored but are expected to violate proposed ozone standards.
• In addition, TEMPO will address the following scientific questions:
• How does air pollution drive climate forcing, and how does climate change affect air quality on a continental scale?
• How can observations from space improve air quality forecasts and assessments?
• How does intercontinental transport affect air quality?
• How do episodic events, such as wildfires, dust outbreaks, and volcanic eruptions, affect atmospheric composition and air quality?

Pollution monitoring implications

The EPA “Good Neighbor” plan is designed to reduce ozone pollution from upwind states. The plan has been subjected to may legal assaults and is currently scheduled to be reviewed by the U.S. Supreme Court, notes Courthouse News.

“Under the Clean Air Act (CAA), states are responsible for developing state implementation plans to ensure they meet National Ambient Air Quality Standards (NAAQS). The federal government can only implement a federal implementation plan, such as the good neighbor plan, if it finds that the state implementation plan is deficient,” says Roll Call.

Many states have questioned the EPA modelling used to establish the pollution reductions called for by the Good Neighbor plan.

As an example, Chris Wells, executive director of the Mississippi Department of Environmental Quality, has said that “the rule will require reductions that are disproportionate to his state’s emissions,” Roll Call adds.

"'We simply are not convinced that we have any actual impacts to Texas air quality,’ said Wells. ‘And the process that EPA followed here did not afford us the opportunity that we should have been given to really evaluate that modeling.’”

The data from TEMPO could be a game-changer.

“The [EPA] will use the measurements [from TEMPO] to provide public data, pollution forecasts and inventories,” continues The Gazette.

Once this data becomes readily available, the technology is expected to pinpoint pollution sources, including accounting for pollution from other sources such as wildfires in other countries, which will provide the EPA with better data to combat challenges to its ground-level monitoring system data.