Dozens of temporary gas turbines in Mississippi powering a huge SpaceXAI data centre in neighbouring Tennessee have caused a major spike in nitrogen oxide air pollution, satellite data suggests. SpaceXAI and local authorities dispute the claim.
SpaceXAIās Colossus 2 data centre in Tennessee came online in 2025 and is now the largest operational data centre in the US, servicing the firmās rapidly growing artificial intelligence technology.
However, the site has been embroiled in controversy over its use of temporary gas turbines. Campaigners say these turbines are contributing to hazardous levels of air pollution in the surrounding area, and there are over their use, pursued by campaigners and local residents against SpaceXAI and its subsidiary MZX Tech.
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Normally, emissions of NOx and other air pollutants from gas power plants are controlled using catalytic converters, but most of the temporary turbines powering the Colossus 2 plant donāt have them fitted.
NOx gases can inflame the airways and exacerbate the symptoms of people already suffering from lung or heart conditions. They also react with other air pollutants to form ozone and particulate matter, both key components of urban smog.
at the Massachusetts Institute of Technology and his colleagues used observations from NASAās TEMPO satellite ā to monitor air pollution over North America ā to assess the impact of the Colossus 2 plant on local air quality.
The satellite observations show a āstrong increaseā in local NOx concentrations from late 2025 onwards, according to the study by Gauldās team, which is when SpaceXAI began deploying the temporary turbines to Colossus 2.
The researchers then used the TEMPO satellite to calculate two-week-average NOx source rates from August 2025 to mid-August 2026. They first detected NOx emissions in December 2025, and emissions increased throughout the study period. The number of turbines on the site , from to .
The satellite analysis suggests that emissions averaged about 730 kilograms per hour between February and August 2026, peaking at 1180 kg per hour in August 2026. By comparison, the monthly emissions from a nearby gas power plant in Mississippi averaged just 21 kilograms per hour of NOx emissions, the paper reports.
at the University of Leeds in the UK, who wasnāt involved in the study, says the pollution levels observed by the satellite are significant. āThe values they report in the vicinity of the [temporary turbines] are values that we have seen over central London,ā he says.
at the University of California, Berkeley, says the paper is āsolidā science. āItās very clear that thereās a huge number of uncontrolled generators on this site, generators without emissions controls on them,ā he says. āThereās a lot of electricity being created, and they are putting a lot of NO2 [the most commonly regulated NOx gas] into the atmosphere.ā
at Minerva University, California, who worked on the development of the TEMPO satellite, says the NOx emissions, as calculated in the paper, would mean each turbine was producing roughly the same level of emissions each year as 50,000 cars. He called for further work to quantify the health impacts of the emissions, including measuring any change in the local levels of ozone pollution since the opening of the site.
In July 2026, SpaceXAI to remove all 69 temporary turbines by July 2027 and replace them with 41 permanent gas turbines. The company was to construct the permanent gas turbines in March 2026 by the Mississippi Department of Environmental Quality (MDEQ). SpaceXAI also promised that all of the mobile turbines it uses ā which it is starting to manufacture in-house ā will be fitted with pollution-control technology.
āMaking sure these converters are fitted to these power generation systems is very important,ā says Zoogman. āIt does make a very large difference.ā
However, the satellite study concludes that the current average emissions rate from the temporary turbines is about 16 times higher than it is expected to be once the permanent turbines are installed.
Responding to queries from Ā鶹“«Ć½, SpaceXAI sent a from a third-party air-quality expert, which claims local air-quality monitoring stations havenāt observed notable increases in pollution concentrations since the mobile generators began operating. It said the emissions from the site fall within the relevant regulatory requirements.
A statement from MDEQ in response to questions from New Scientist said: āMDEQ does not comment on third-party reports or matters involved in pending litigation. MDEQ recognizes the public interest in this facility and remains committed to carrying out its responsibility to protect public health and the environment through implementation and enforcement of applicable state and federal environmental laws and regulations.ā
The satellite analysis comes as concern grows over the rapid rollout of new gas power to run the massive new data centres that underpin the booming AI sector. US gas-fired power under development , according to Global Energy Monitor, an independent non-profit.
Meanwhile, almost half of the proposals for powering data centres with gas involve using gas turbines and engines. These are less efficient and more polluting than ā which reuse waste heat from one turbine to power another ā but are quicker to deploy. Experts warn this new gas build-out will lock in decades of additional carbon emissions and worsen air quality. Many data centres also rely on diesel generators for back-up power, which emit high levels of NOx and other pollutants.
Data centres may also need close monitoring to check that the new dedicated power plants supporting the facilities are meeting regulatory requirements. āThatās why having this public attention on it is really valuable,ā says Zoogman. āI think itās important to have this technology to do the monitoring and the assessment and figure out where the pollution is coming from.ā
Rapid advances in satellite technology mean they are increasingly being used to spot unreported emissions across a whole range of sectors, including oil and gas infrastructure, landfills and manufacturing facilities.
arXiv
