In addition to reducing greenhouse gas pollution and combating climate change, Initiative 1631 would clear dangerous pollution out of Washington’s air, saving lives and slashing health care costs by billions of dollars in the Evergreen State.

Any time fossil fuels are burned, both air pollution and climate pollution enter the air. The aim of I-1631 is to reduce climate pollution but it will simultaneously cut the air pollution that makes people sick, including a reduction in minuscule particles called PM 2.5, nitrogen oxide (NOx), and volatile organic compounds that create ground-level ozone.  

I-1631 would raise close to a billion dollars a year through a carbon fee on large polluters, including the distributors of transportation fuels in Washington. The state would invest 70 percent of revenue from the fee in “clean air and clean energy” projects, likely including electric vehicles and alternative fuels. The fee also would presumably encourage businesses to find cleaner alternatives to dirty fuels, in turn growing Washington’s clean energy businesses.

The aim of I-1631 is to reduce climate pollution but it will simultaneously cut the air pollution that makes people sick.
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PM 2.5 and smog are dangerous pollutants

PM 2.5 stands for particulate matter of 2.5 microns in width or less—that’s significantly smaller than the width of a human hair. Despite its size, it’s a concerning type of pollutant because these tiny particles get lodged in the lungs and are associated with heart attacks, asthma aggravation, decreased lung function, and cancer. PM 2.5 is especially concerning for babies, children, elderly people, and adults with heart and lung disease and other chronic illnesses. The Washington Department of Health has identified PM 2.5 levels as a key indicator for public health. An increase in wildfires, more frequent and more powerful because of climate change, means Washingtonians will breathe more PM 2.5 via fire smoke. This summer, people in Seattle were choking on haze due to wildfires and the area experienced some of the worst air quality in the world—Seattle is one of only four cities in the United States that experienced more spikes in PM 2.5 from 2014 to 2016 compared to the prior two years.

PM 2.5 isn’t the only pollutant that can have harmful effects on health. Ground-level ozone, also known as smog, worsens lung diseases such as asthma, bronchitis, and emphysema. When cars and trucks burn fuel, they spew NOx and volatile organic compounds, which then combine with oxygen and sunlight to form smog. On hotter and sunnier days, more smog forms. PM 2.5 has a greater negative impact on human health than NOx on a per-ton basis, and NOx and volatile organic compounds mostly affect human health by producing PM 2.5 under certain seasonal and atmospheric conditions.

A warming climate with more frequent and extreme heat waves (added to the heat island effect in cities) leads to higher concentrations of ground-level ozone. Polluted, smoggy air can cause lung irritation, chest pain, coughing, and congestion, as well as breathing difficulties during outdoor exercise or activities.  

I-1631 will slash air pollution

I-1631 has two mechanisms for cutting pollution. First, the fee itself will discourage polluters and drive investment to more efficient use of energy and adoption of cleaner energy sources.

Second, the state will invest most of the revenue from the fee into clean air and clean energy projects that will reduce pollution even more.

Puget Sound Clean Air Agency, overseeing the four-county region where more than half of the people in Washington live, recently analyzed some of the likely air pollution benefits of I-1631. The study concluded that the effect of the price signal alone (excluding the anticipated investments in clean energy projects using fee revenues) would reduce 350 to 450 tons of PM 2.5 from cars and trucks in the Puget Sound region from 2020 through 2035. That would be the equivalent of taking about 200,000 cars off the road. I-1631’s clean air investments would filter even more pollution out of the air. The agency estimated if 35 percent of the I-1631 revenue is invested into programs to reduce diesel pollution, those programs would cut nearly 1,000 tons of PM 2.5 pollution during the first 15 years after implementation. That’s a pollution reduction equivalent to removing half of all vehicles from the roads in the region. We extrapolate that if I-1631 invested in similar projects across the state, not just in the Puget Sound Region, Washington could cut around 1,500 tons of PM 2.5 by 2035.

Cutting air pollution saves lives and helps public health

In 2017, the Center for Health and the Global Environment at Harvard University analyzed some of the potential health benefits of a carbon price proposed in Massachusetts, where the proposed fee was similar to I-1631. Though the proposals varied there are lessons to draw from the study’s findings. For reference, the pollution price for the Massachusetts proposal rose faster and had a lower maximum than Washington’s—it started at $10 per ton of CO2 equivalents and plateaued at $40 per ton after seven years. I-1631 would start at $15 per ton of CO2 pollution and, assuming 2 percent inflation, reach $55 per ton after 15 years. The Harvard study only analyzed the benefits from the fee itself, not form any potential investments of the fee revenue.

Massachusetts’ fee would have cut NOx, PM 2.5, sulfur dioxide, and volatile organic compound pollution from four key sectors in the state. The greatest reductions were found in motor gasoline use, followed by natural gas for heating, diesel fuel use for transportation, and oil for heating. Washington probably does not use as much heating fuel as Massachusetts, so the findings might be a little different in the Evergreen state.

We project that Washington could avoid putting between 1,413 and 1,579 tons of PM 2.5 into the air by 2035, which would save 68 to 76 lives.
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The study also found that, over a 24-year period, the carbon fee in Massachusetts could save 340 lives, avoid 54 hospitalizations for respiratory and cardiovascular illnesses, and avoid 20 heart attacks. Though the study did not quantify them, the authors noted that reduced pollution would have other health benefits, including reduced asthma attacks, fewer lost days of work and school, and reductions in autism, Alzheimer’s disease, premature birth, and low birth weight.

One of the most important levers in realizing the public health benefits of I-1631 is reducing PM 2.5 levels. Using the data from the Puget Sound Clean Air Agency study, we project that Washington could avoid putting between 1,413 and 1,579 tons of PM 2.5 into the air by 2035, which would save 68 to 76 lives, avoid 34 to 38 avoided hospitalizations for respiratory and cardiovascular illnesses, and avoid 8 heart attacks.

Helping public health saves money

The Harvard study’s aim was to quantify the health and climate benefits of the carbon fee. In addition to preventing some deaths, heart attacks, and hospitalizations, researchers concluded the fee would result in $2.9 billion ($2017 USD) of cumulative health benefits between 2017 and 2040.

Washington uses about 47 percent more transportation fuel than Massachusetts and I-1631’s price will go higher than the proposed Massachusetts policy. The Washington fee could save even more lives, avoid even more heart attacks, and outpace the $2.9 billion in cumulative health benefits in 2040 estimated by the Harvard study.

  • It also invests revenue from the fee into projects aimed at growing clean energy and reducing pollution even further than what the Harvard study quantified. The exact investments under I-1631 remain to be determined but could include rebates or grants to purchase or lease zero-emission cars and grants to assist public and private sector fleets to transition to lower emission or zero-emission buses and trucks. This kind of funding would both reduce Washington’s reliance on gasoline and diesel, and reduce the associated air pollution as Puget Sound Clean Air Agency suggested.

    There’s also I-1631 money earmarked to help the communities in Washington that experience the highest levels of air pollution and consequent health impacts. I-1631 tasks the Washington State Department of Health, along with University of Washington researchers, to identify “pollution and health action areas” in order to prioritize investments and projects that would directly benefit communities with significant air pollution. Neighborhoods with the highest concentrations of PM 2.5 and NOx—those along the I-5 corridor in South Seattle, for example—experience higher rates of cancer, premature death, and asthma. Plans for these areas will be developed through meaningful consultation with community members already facing these disproportionate health burdens.

    If I-1631 passes, it will reduce the human and economic costs of fewer heart attacks, asthma attacks, premature births and low birth weights, and the host of other illnesses worsened by air pollution.
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    The Puget Sound Clean Air Agency estimated the effect of the fee alone (irrespective of investments in clean energy projects) would yield around $35 million per year in public health benefits in the Puget Sound region. Based on the agency’s numbers, we estimate the investments could generate roughly another $2.2 billion by 2035 (in-line with the Harvard study’s findings).

    Health benefits will come quickly

    Cleaning the air will immediately improve health. As PM 2.5 levels drop and smoggy days become less frequent, fewer Washingtonians will get sick or die from pollution exposure.

    As they cast their ballots this fall, many voters will be weighing the disastrous medium- and long-term consequences of climate change against short-term pains like some of the fee being passed along in fuel costs. But voters can add an important short-term benefit to the scales—if I-1631 passes, it will reduce the human and economic costs of fewer heart attacks, asthma attacks, premature births, and low birth weights, and the host of other illnesses worsened by air pollution. Health professionals recognize these benefits and support I-1631 because of it. Washington medical societies, including the state academies of family physicians, pediatricians and internists, nursing organizations and unions, the American Lung Association, and Virginia Mason have all endorsed the initiative.

    Laura Skelton is the Executive Director of Washington Physicians for Social Responsibility. She is a primary author on over 20 sustainability curriculum publications, including a full-length high school textbook on sustainability challenges and solutions. Laura spent several years as a science and global issues educator, teaching undergraduate labs, high school and middle school courses. She holds a master’s degree in ecology from the University of Georgia’s Odum School of Ecology and a bachelor’s in ecology and society from Hendrix College. 

    Sarah Cornett is the Climate Programs Organizer for Washington Physicians for Social Responsibility. Sarah organizes WPSR’s Climate Program, representing members in Washington coalitions to advocate for clean energy and environmental justice. Her organizing background includes a progressive political campaign in rural Missouri and food access movements. Sarah comes to WPSR from St. Louis, where she received public policy and organizing training through a Coro Fellowship in Public Affairs. 

    Thanks to Trygve Madsen for his help researching this article.


    To estimate between 1,413 and 1,579 tons of PM 2.5 into the air by 2035

    • The target region of the Puget Sound study (Kitsap, Pierce, King, and Snohomish Counties) represents 60 percent of the population in Washington (based on the 2017 ACS estimate available at and the remaining counties make up the remaining 40 percent.
    • The Puget Sound study authors estimate that over the 16-year period, the increasing price will reduce PM 2.5 emissions by 350-450 tons in the Puget Sound area. They also estimate that from 2020-2022, there will be an additional 500 tons of PM 2.5 reductions from revenue-funded projects targeting emissions reduction.
    • We assume that Puget Sound and the rest of Washington will respond the same to emissions reduction projects and fee increases, and calculate project-driven and fee-driven reductions in WA:
      • 350 low / 450 high / 500 project-based (tons Puget sound estimate) * 40% (rest of Washington population %) / 60% (Puget Sound population %). That yields low and high bounds of 232 and 298 for the fee-driven reductions and 331 for project-based reductions. Summing the totals from Puget Sound and the rest of the state yields the projected range of PM 2.5 reductions over this period.

    To estimate $2.2 billion in savings by 2035

    • The Puget Sound Report estimated that removing 18-24 tons of PM in 2025 (table 1) would yield up to $35M in annual total health benefits (table 2). That’s an average of $1.5M per ton. If investments would remove about 1,500 tons of PM by 2035 (see above) and each ton yields similar health benefits, then $1.5M * 1,500 = $2.2B.