Nov 6, 2025

Data centers could produce “digital smog” by increasing power plant emissions and relying on backup generators during blackouts.

Above, an aerial view of a new I-70 highway development through Denver’s Elyria-Swansea neighborhood in 2022. The highway, heavy industry, and soon a data center are sources of air pollution for the neighborhood.

Matthew Staver/For the Washington Post

It’s been almost four years since Julie Mote moved into Viña Apartments, an affordable housing complex in north Denver’s Elyria-Swansea neighborhood. Since then, she learned bad air is a fact of life in the largely Latino area packed with highways and heavy industry.

“I can’t leave my windows open,” Mote said. “When it’s a nice, cool day or whatever, the air is horrible. It stinks. You can smell the gas.”

Mote blames the odors on a nearby oil refinery and dog food factory.

Now, Denver-based data center company Core Site is building its latest facility across the street from her apartment. Once the company completes the first portion of the project, she worries the neighborhood will have yet another source of toxic air pollution.

“I just wanna move, you know? But unfortunately, I’m low-income,” Mote said.

Data centers are popping up nationwide to power the AI boom. Those facilities gobble up electricity and water, but their massive appetite for resources isn’t the only environmental concern. Residents in north Denver worry the CoreSite data center could also bathe their neighborhood in dangerous light, noise, and air pollution.

It might seem odd to worry about bad air from a data center. The facilities, after all, are plain, hulking buildings packed with computers, not factories with smokestacks and machines that grind raw materials into dust.

The pollution, however, comes from two less visible sources, according to Shaolei Ren, an associate professor of computer engineering at the University of California.

Connecting data centers to the grid requires additional generation at fossil fuel power plants, increasing climate-warming emissions and other pollutants, like particulate matter. The facilities also house massive backup diesel generators to maintain 24/7 operations. Once the company flips the system on, the resulting exhaust could release nitrogen dioxide, particulate matter, and other pollutants into the surrounding neighborhood.

An analysis Ren co-published last year estimated the potential air quality impact. By 2028, he expects AI air pollution — what he calls “digital smog” — will lead to new asthma and cancer cases, costing the U.S. up to an extra $20 billion in annual public health costs.

Luckily, Ren thinks there’s a straightforward solution: Put AI data centers far away from dense urban areas.

“If you choose the location in a better way, you can significantly reduce the health impact,” Ren said.

The future CoreSite data center, however, won’t sit far from vulnerable populations. Besides the affordable housing complex, a low-income health clinic, and future senior living facility are less than a block from the construction site. A small park with a city rec center is only slightly further away.

Megan Ruszkowski, a CoreSite spokesperson, said the company chose the location because the property was already zoned for industrial use. It also sits a few miles from the company’s two existing data centers in Denver, which Ruszkowski said will cut lag times and ensure rapid responses for future AI customers.

But that doesn’t sit well with Ana Varela, a community activist and resident living in Elyria-Swansea. She said the company failed to properly inform residents and gather feedback before it began construction. The first portion of the data center is now set to begin operations in mid-2026.

“This community deserves so much more,” Varela said. “We deserve to be treated like any other gorgeous, historic neighborhood in Denver.”

CoreSite insists its data center won’t have a significant impact on local air quality; that’s because its state air pollution permit only allows the company to run its 5,000-horsepower backup generators during blackouts or for short, daytime testing runs.

But Varela said the company can go one step further. If it thinks air pollution won’t be an issue, she said it should install air monitors and let residents see exactly what types of toxins and emissions are coming from the facility.

That way, other communities could also learn what it means to have a data center next door.

Read more* about this story and see pictures of CoreSite’s future data center at Colorado Public Radio.*