New Analysis Finds Climate Change Worsens Harmful Ozone Levels in Colorado’s Front Range

Frontline Communities Disproportionately Bear the Burden

Published Sep 10, 2021

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CAMBRIDGE, Mass. (September 10, 2021)—Higher temperatures brought on by climate change since the 1950s have driven formation of ground-level ozone, a respiratory irritant that poses disproportionately high health risks in Colorado’s Front Range, according to a paper just published in the Journal of Exposure Science and Environmental Epidemiology, published by Springer Nature, by scientists at National Jewish Health in Denver and the Union of Concerned Scientists (UCS).

The team quantified the historical “ozone climate penalty”—the impact that recent climate change has had on ozone concentrations—in the Denver Metro North Front Range (DMNFR), a region that has historically struggled with high levels of air pollution. The study concluded that the additional ozone attributed to recent climate warming has delayed the DMNFR’s ability to meet national ozone standards by two years.

“For people living in Colorado’s Front Range, the impacts of climate change aren’t an abstraction of the future,” said Dr. James L. Crooks, a researcher at National Jewish Health based in Denver. “Ground-level ozone is a major public health concern and it’s already affecting Colorado communities in a big way.”

Ozone can cause acute physical symptoms, such as eye and ear irritation, while also exacerbating chronic respiratory diseases and interfering with lung function. While several studies have linked high ozone levels in the DMNFR region to various local and regional factors, this paper is the first to attribute climate change’s role in ground-level ozone pollution in the region. As a result, the study provides a framework for uncovering climate change’s role in ground-level ozone pollution in other impacted areas.

The analysis also found that neighborhoods with a larger proportion of Hispanic residents, residents with asthma or diabetes, and residents without health insurance are already experiencing the greatest climate penalty.

“We know that the rising temperatures have sped up ozone production,” said Dr. Crooks. “Our data show that the consequences are already falling hard on historically disenfranchised and frontline communities. Additionally, these communities have the most to gain from widespread emissions reductions.”

Researchers analyzed the climate penalty to help affected communities prepare for future impacts and access public health services that may help with the harm that has already occurred.

“To make a real difference in tackling climate change and ozone pollution, we need to center the frontline communities that feel these burdens the hardest,” said Dr. Rachel Licker, a senior climate scientist at UCS. “As climate change progresses, the climate penalty grows, making it increasingly difficult to achieve national ozone standards. In other words, the longer we wait, the bigger the challenge gets. To safeguard people’s health, we need to take swift and aggressive action to reduce heat-trapping emissions. We also hope others will do more local analyses like this to inform policymakers who can deploy the necessary public health resources.”

Other report authors include Dr. Adrienne Hollis, Principal at Hollis Environmental Consulting, and Dr. Brenda Ekwurzel, the director of climate science and a senior climate scientist at UCS.