Ozone pollution will harm tens of millions of people at current pace

A recent investigation reveals a concerning forecast for ozone pollution levels across the United States by 2050, indicating potential non-compliance with air quality standards and increased public health risks.

This study paints a detailed picture of how climate-induced changes could intensify ground-level ozone, a molecule composed of three oxygen atoms.

What is ozone pollution?

Ozone pollution, also known as ground-level ozone, refers to the presence of ozone gas (O₃) in the Earth’s lower atmosphere. Unlike the protective ozone layer in the stratosphere, ground-level ozone is a harmful pollutant.

It forms when nitrogen oxides (NOx) and volatile organic compounds (VOCs) react in the presence of sunlight. Common sources of these pollutants include vehicle emissions, industrial facilities, and chemical solvents.

Ozone pollution poses significant health risks. It can cause respiratory problems, aggravate asthma, reduce lung function, and increase susceptibility to respiratory infections.

Long-term exposure can lead to chronic respiratory diseases and even premature death. Additionally, ground-level ozone can harm ecosystems, damaging crops, forests, and wildlife.

Climate change exacerbates ozone pollution by increasing temperatures, which accelerates the chemical reactions that produce ozone. Efforts to control ozone levels focus on reducing NOx and VOC emissions through regulatory measures and technological advancements.

Ozone pollution on the rise

Ground-level ozone isn’t just a minor irritant; it’s a major health hazard, linked to reduced lung function and airway inflammation, contributing to hundreds of thousands of deaths annually.

Study lead author James East, a former PhD student at North Carolina State University, is now a researcher at Harvard University.

“Climate change influences ozone formation through a myriad of factors. Predominantly, warmer temperatures correlate with ozone increases in already polluted areas. Furthermore, expected rises in naturally occurring VOC emissions, particularly in regions like the Southeast U.S., could worsen the situation,” explained East.

The study, “Projecting Changes in the Frequency and Magnitude of Ozone Pollution Events Under Uncertain Climate Sensitivity,” navigates through these complexities.

The research extends beyond mere predictions, incorporating various models and statistical tools to gauge future ozone pollution landscapes. In particular, the study explores how often (and by how much) ozone levels might exceed public health standards by mid-century.

Air quality thresholds

The results of the study are presented as a range, acknowledging the ongoing debates among climate scientists about how drastically the climate reacts to greenhouse gas concentrations.

“The best-case scenario, with low climate sensitivity to carbon dioxide, suggests an average increase in peak ozone levels by less than 0.3 parts per billion (ppb),” noted East. “This increase might still keep many areas within safe air quality thresholds.”

However, East warns of a less optimistic outcome where the climate shows high sensitivity to carbon dioxide.

Here, peak ozone levels could rise by more than 2.3 ppb on average, leading to a significant increase in days where ozone levels surpass air quality norms.

Implications for public health and policy

The practical implications of these findings are stark. “Our study estimates that between 5 million and 13 million additional people could be exposed to dangerously high ozone levels by 2050,” said East.

This projection is crucial for policymakers, especially those involved in the Environmental Protection Agency’s ongoing review of the ozone air quality standards.

Fernando Garcia Menendez, the study’s corresponding author and an associate professor of environmental engineering at NC State, emphasized the broader significance of these insights.

“While state and federal governments strive to control ozone levels through emissions reductions, our findings suggest these efforts might be less effective in the future, particularly in areas already struggling to meet air quality standards,” said Menendez.

“This research not only deepens our understanding of climate change’s impact on air quality but also aids in refining the cost-benefit analyses of climate regulations and related technological advances.”

Strategic responses to ozone challenges

This work underscores the need for a proactive approach in reviewing and possibly revising air quality standards to better protect public health in the face of evolving climate conditions.

By offering a clearer picture of the potential scenarios, the research arms policymakers with vital data to make informed decisions, potentially leading to more robust strategies to mitigate the adverse effects of ozone pollution.

As climate patterns continue to shift, such studies will be pivotal in guiding effective responses to safeguard environmental and public health.

The study is published in the journal Earth’s Future.

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