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Expand chart
Descartes Labs via ESA; Map: Harry Stevens/Axios

This map shows a 2-month average of the abundance of nitrogen dioxide (NO2) in the air, as sensed from space by the new Sentinel-5P satellite from the European Space Agency.

Why it matters: The image, generated by scientists and data specialists at the space data analysis firm Descartes Labs, shows us the human footprint on the planet. "I find it fascinating that this image would be mostly blank if people weren't here burning stuff," says Tim Wallace, creative lead at Descartes Labs.

Nitrogen dioxide is part of a group of gases referred to as nitrogen oxides, or NOx. NOx is a key contributor to smog and a major health hazard, so monitoring it will help track its major sources.

"Whenever we're burning for either power production or transportation, anything that we’re burning is going to emit NOx," Laura Mazzaro, an atmospheric scientist and environmental engineer at Descartes Labs, tells Axios.

The big picture: NOx has a short atmospheric lifetime, on the scale of hours, so satellite sensors can give a near-real-time picture of combustion worldwide, from the cars leading to Los Angeles smog to biomass burning in the vast forests of Indonesia and South America.

"It affects people's quality of life directly," Mazzaro says.

A lot of point sources visible in the image are to be expected, such as major cities and oil production hubs. However, the hazy bands of NOx over the Amazon and sub-Saharan Africa may be clues to different sources of the compound, and interestingly, the satellite is even able to show typically used shipping routes.

Why you'll hear about this again: Mazzaro says the Sentinel satellite's capabilities could be used for monitoring compliance with environmental agreements, including air pollution reduction commitments on NOx, acid rain and any future regulations on methane pollution, given that it is a potent greenhouse gas that is on the increase.

Go deeper: What We Burn Creates an Eerily Navigable Map of Earth (Medium)

Go deeper

DOJ watchdog to probe whether officials sought to alter election results

Former President Donald Trump and former First Lady Melania Trump exit Air Force One in West Palm Beach, Florida, on Jan. 20. Photo: Alex Edelman/AFP via Getty Images

The Justice Department's inspector general will investigate whether any current or former DOJ officials "engaged in an improper attempt to have DOJ seek to alter the outcome" of the 2020 election, the agency announced Monday.

Driving the news: The investigation comes in the wake of a New York Times report that alleged that Jeffrey Clark, the head of DOJ's civil division, had plotted with President Trump to oust acting Attorney General Jeffery Rosen in a scheme to overturn the election results in Georgia.

2 hours ago - Podcasts

Google's chief health officer Karen DeSalvo on vaccinating America

Google on Monday became the latest Big Tech company to get involved with COVID-19 vaccinations. Not just by doing things like incorporating vaccination sites into its maps, but by helping to turn some of its offices and parking lots into vaccination sites.

Axios Re:Cap goes deeper into what Google is doing, and why now, with Dr. Karen DeSalvo, Google's chief health officer who previously worked at HHS and as health commissioner for New Orleans.

Biden signs order overturning Trump's transgender military ban

Photo: Tom Brenner/Getty Images

President Biden signed an executive order on Monday overturning the Trump administration's ban on transgender Americans serving in the military.

Why it matters: The ban, which allowed the military to bar openly transgender recruits and discharge people for not living as their sex assigned at birth, affected up to 15,000 service members, according to tallies from the National Center for Transgender Equality and Transgender American Veterans Association.