Larimer County proclaims May 2025 National Clean Air Month after air-quality update and new monitoring plans

Larimer County health officials on Tuesday updated the Board of County Commissioners on local efforts to cut ground-level ozone and other air pollutants and the board joined the county Board of Health in proclaiming May 2025 National Clean Air Month.

The update focused on the causes of ground-level ozone, monitoring upgrades, grant-funded monitoring and outreach programs, and a commercial landscaping electrification voucher program intended to reduce emissions from gas-powered lawn equipment.

Tom Gonzales, Larimer County public health director, said the primary air-quality challenge is ground-level ozone, formed when nitrogen oxides and volatile organic compounds react in heat and sunlight. "The problem is ground level ozone," Gonzales said, noting that vehicle emissions make up "over 70%" of precursor emissions in the county and that hot days — typically 90 degrees or higher — are strongly correlated with exceedances of the federal ozone standard.

Noelle Udell, environmental health specialist lead, described the county's relaunch of an electrification grant for commercial landscapers. "Recipients will be awarded up to $6,000 per voucher," she said, adding that vouchers will pay for certified commercial battery-powered landscaping equipment from participating retailers and that the county will provide free safety kits to recipients. Udell said about "10 to 12" applicants from the prior application cycle will be selected, with priority for historically underrepresented and minority-owned businesses.

Leah Snyder, environmental health planner and air-quality supervisor, told commissioners the county is expanding its regulatory monitoring network. Snyder said three new regulatory-grade monitors have been added or upgraded in Timnath, at Fossil Creek Reservoir and at Mahaffey Park in Loveland, and that an expanded particulate monitor now operates at the Timnath site. She also described a multi-year research project led by Colorado State University, the Regional Air Quality Council and the Air Pollution Control Division that received roughly $1.3 million to monitor NOx and VOCs over the next three years.

Officials said the county received a $500,000 EPA air toxics grant to monitor air toxics in more burdened communities and to expand outreach; projects under that grant include stationary monitoring near schools, mobile monitoring along busy corridors and community-focused education displays. Udell noted past ozone modeling showing gas-powered lawn and garden equipment can account for about 6% of ozone on high-ozone days in Larimer County, and she compared one hour of gas-powered mowing to roughly "driving 300 miles" in emissions.

Gonzales and staff stressed the region's geographic background ozone — often about 45–50 parts per billion on warm days — makes achieving the 2015 EPA ozone standard of 70 parts per billion more difficult. Gonzales said the Colorado Department of Public Health and Environment's request to reclassify the Northern Front Range nonattainment area from "serious" to "severe" is intended to open additional federal tools and potentially extend compliance timelines, though it could carry costs such as changes to summer fuel blends.

After discussion, Commissioner John Kefalas read a joint proclamation recognizing May 2025 as National Clean Air Month in Larimer County. Kefalas moved to approve the proclamation; the board voted 2 to 0 in favor.

The county plans to continue outreach, expand monitoring, promote electrification incentives and coordinate regionally with the Regional Air Quality Council, Colorado State University and state agencies as part of its strategy to reduce ozone precursors and improve local air quality.