Texas Data Centers Could Erase Two Decades of Air Quality Gains, HARC Modeling Warns

The Houston Advanced Research Center (HARC) has published a report modeling how planned Texas data center projects could affect the state's air quality. In one scenario, fine particle pollution (microscopic soot particles small enough to reach deep into the lungs) from Texas's power sector would more than triple, reaching its highest level since 2006, according to The Verge.

That scenario assumes every planned project connects to the grid and is powered by the anticipated grid mix. Under those conditions, HARC finds that soot and smog-forming pollutants would rise sharply, erasing decades of air quality gains within about five years. Power-sector nitrogen oxide (NOx) emissions, a key smog precursor produced when fuel burns at high temperatures, would increase 136 percent, approaching 2004 levels. Carbon dioxide would climb 90 percent above 2025 levels. HARC ran three projections for data center energy demand, and the pollution figures carry real uncertainty, since many proposed projects are speculative.

The power supply choice drives much of the spread. According to the report, NOx emissions could be up to 10 times lower if facilities pair grid power with onsite renewable electricity, such as solar generation at the site. Onsite gas engines would produce the highest possible pollution levels. Developers are also turning to less efficient gas turbines, which burn more fuel per unit of power, to accelerate construction. That shift makes the buildout more polluting.

Texas is the largest data center market by power capacity, with 26 gigawatts existing and under construction, according to JLL. A Wood Mackenzie report published in March 2026 found Texas has four times more proposed data center capacity running on onsite-generated power than any other state.

The modeling sits against a long decline. HARC's Texas Data Centers and Air Quality assessment finds the state cut its major air pollutants sharply between 2002 and 2024, with the largest reductions coming from transportation, industry and power generation. The Texas Tribune reported on October 20, 2026 that the new work warns those gains could be reversed by the end of the decade, especially if data centers rely on natural gas. Truthout reports that a net zero scenario, in which data centers draw on cleaner sources, still projects a 35 percent rise in statewide NOx by 2031. KWTX, citing the report, counts at least 288 planned projects across Texas and describes modeled emissions ranging from a marginal increase to a reversal of two decades of progress. CBS Austin reports that NOx could be two to 10 times higher on the modeled path.

HARC CEO John Hall said there is a good chance children and grandchildren will breathe dirtier air than previous generations, and that decades of emissions progress are now at risk.

An Amazon-owned site in Pecos County received a permit to release up to 33 million tons of CO2 to power its AI data center, according to The Verge. The Trump administration's EPA has proposed scrapping a federal air pollution rule that would let data centers hide their air pollution, per The Verge.

The Environmental Defense Fund reported that turbines and generators planned for Texas data centers are permitted to emit more than 1,000 tons of harmful air pollutants and 1.6 million tons of greenhouse gases. It also counted 32 polluting gas-fired plants planned in Texas to supply data center power, more than in any other state. Microsoft's carbon pollution rose 25 percent in 2025, according to its latest sustainability report. A University of Texas study projects that data center growth could raise the state's water use by as much as 9 percent by 2040. An MIT study on the air quality and health impacts of data center electricity demand found that the generation attributable to that demand is largely supplied by fossil fuel units.

In my view, the most useful reading of the HARC work is that the outcome is a matter of procurement and design rather than a fixed trajectory. The spread between the scenarios is wide, and much of it rests on whether projects are built around grid power, onsite renewables or onsite gas, along with how many of the proposed facilities are ever built. That uncertainty cuts both ways. Texas has already shown it can cut emissions across two decades while its economy grew. Cleaner onsite generation, combined with the kind of emissions transparency the EDF has called for, is the lever that would keep that trend intact.