Wildfire haze from Canada has been lying heavy over the mountains this week and more could be on the way from California.

State public health department data shows Colorado Springs air quality reached unhealthy levels Tuesday and Wednesday with ground ozone levels above the federal limit. Later in the week the air quality was not as bad, but still unhealthy for sensitive people, such as those with asthma.

High ozone levels can inflame and damage human lungs, increase asthma attacks and lead to premature death. It can also cause plants to brown and lower crop yield, according to the Environmental Protection Agency.

The week of haze was expected to clear out Friday night with help from westerly winds, but more wildfire smoke could move in from fires in California, said Kathleen Torgerson, meteorologist with the National Weather Service.

It is tough to forecast ozone levels for the rest of the summer, but long-range models suggest the coming months will be hotter and drier than usual, which contributes to ground-level ozone, according to a statement from the Colorado Department of Public Health and Environment.

Sunlight along with pollution emitted from power plants, cars, wildfires and other sources form the ozone that can stick around in the atmosphere for a month or more. It can flow into the other areas that do not have many local sources of pollution, such as Rocky Mountain National Park, where ozone has damaged plants, said University of Colorado Boulder Professor Daven Henze, who has done research on air quality.

Nationally more stringent emission standards on cars and power plants have helped lower ozone levels, Henze said, but the Denver metro area has been an exception. In 2022, the area was reclassified as severe under the national ambient air quality ozone standards.

In recent years, the Pikes Peak region has also seen high ozone days, putting it at risk for falling into federal nonattainment of air quality standards, which could trigger new regulations. For example, many Denver metro residents must have their cars tested for emissions.

At the same time, the state has set aggressive targets to cut pollution. As part of those goals all of the state’s coal-fired power plants are set to close by 2031.

In Colorado Springs, the Martin Drake Power Plant stopped burning coal in 2021, massively dropping its production of nitrogen oxides also known as NOx, which contribute to ozone.

Colorado Springs Utilities said in a statement the coal production from Drake was producing 4,944.27 tons of NOx in 2005. In 2023 the new natural gas generators produced 65.50 tons of NOx, a reduction of 4,878.77 tons per year.

The single largest producer of NOx in the region currently is the Colorado Springs Utilities’ coal-powered Ray Nixon Power Plant. State public health data shows it is responsible for about 1,142 tons of NOx annually. The plant is set to close by 2030.

Closing coal plants also has the immediate health benefit of cutting down on particulates in the air that contribute to lung cancer and heart disease, Henze explained.

Collectively, vehicles are the largest contributors to emissions in the region — and moving away from gas and diesel power can also help cut that pollution.

Data from the Colorado Energy Office shows there are 11,435 battery-powered or hybrid vehicles on the road in El Paso County — up from 2,199 in July 2020. Statewide there are about 134,000 electric cars on the road, state data shows.

Still, wildfire smoke and other forms of out-of-state pollution are making it tough to meet federal standards. Gov. Jared Polis and the governors of Arizona, Utah and Wyoming signed a letter earlier this year, pointing out these challenges.

The letter states that local man-made emissions account for 20% of total ozone in some Western states, while remaining 80% comes from outside the area.

“Multiple Western U.S. states are now finding it difficult or even impossible to implement plans that meet the requirements of the (Clean Air Act),” the letter states. The governors raised the concern because failure to meet the standards could result in sanctions and hurt access to federal highway funds.

The EPA sent a response saying it was committed to working with states to achieve air quality goals and avoiding sanctions. Transportation projects that can show they are reducing emissions are also exempt from sanctions, the letter said.

Earlier this week, the EPA also announced that it was granting the Denver Regional Council of Governments about $200 million to lower emissions from the building sector. It also granted the Colorado Energy Office $129 million to reduce methane emissions from landfills, coal mines and natural seepage, among other projects. Methane stays in the atmosphere for a long time and can contribute to rising ozone levels globally, said Henze.

While large wildfires are likely to continue, cutting pollution is still a worthy goal because it lowers the overall rise in pollution, Henze said.

“We still get the benefit of the impact that we can make,” he said.

Residents can protect themselves from ozone pollution by limiting their exposure. Residents can spend time outside in the mornings or late evenings when ozone pollution is generally lower, according to the state health department.

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