What health and economic benefits might be possible if the Northwest achieves net-zero emissions by 2050?

In addition to the climate benefits of reducing emissions, achieving net-zero by 2050 also reduces pollutant emissions, which come from point sources, such as coal-fired power plants, as well as non-point sources, such as vehicle tailpipe emissions and agriculture, and have a direct health impact on Northwest residents.

If the region were to achieve net-zero emissions based on the least-cost pathway set out in the NZNW Energy Pathways Core Case, Northwesterners could see the following benefits attributed to annual pollutant reductions:

• Health benefits in the Northwest range from 15 to 33 avoided deaths per million people in 2030 and 18 to 40 avoided deaths per million people in 2050.

• Economy-wide savings range from $2.8 billion to $6.2 billion per year in 2030 and $4 billion to $8.9 billion per year in 2050.

The NZNW Health Impacts analysis uses the U.S. Environmental Protection Agency (EPA)’s Co-Benefits Risk Assessment model (COBRA) to assess health and economic benefits attributed to reductions in fine particulate matter (PM_2.5) concentrations, as well as secondary particulate matter. The COBRA model also translates these health metrics into economic benefits using assumptions about economic costs of each type of health impact.

Please see NZNW Health Pollutant Emissions Results for a full discussion of the assumptions, modeling, and impact on health outcomes ‍

Most health benefits occur by 2030, with some additional benefits between 2030 and 2050.

Coal-fired power plants, which retire by 2030 in the Core Case, contribute to high levels of particulate matter. Removing coal from the economy therefore significantly decreases particulate matter and improves health outcomes in 2030. There are also health benefits from reducing vehicle tailpipe emissions through vehicle electrification, especially for heavy trucks that use diesel, which is a large contributor to harmful air pollutants.

Compared to if pollutant emissions were to remain at 2021 levels, the avoided deaths per million people due to reduced pollutant emissions range from 15 to 33 in Idaho, 16 to 37 in Montana, 16 to 36 in Oregon, and 19 to 44 in Washington by 2050, as depicted in the figure below. The higher health benefits in Washington are due to greater population density, as well as higher pollutant emissions from large transportation and industrial sectors.

Deaths are avoided due to improved air quality and attributed to emissions reductions experienced by the population in 2030 and 2050, compared to the emissions levels in 2021. The figure reports low and high estimates to reflect the range of findings in the epidemiological studies of health outcomes from PM_2.5 used in the modeling.

Improved health attributed to annual pollutant reductions yields economic benefits for the Northwest.

Total Northwest economic benefits attributed to annual pollutant reductions range from $2.8 billion to $6.2 billion per year in 2030 and $4 billion to $8.9 billion per year in 2050, with per capita benefits shown below for each of the four Northwest states.

Some hard-to-remove pollutants will remain in 2050 despite achieving net-zero emissions.

There are remaining pollutants in 2050 from non-energy sources that are difficult to address, the majority of which include:

• Ammonia (NH₃) from livestock and fertilizer

• Nitrous dioxide (NO₂) from background biogenic sources (vegetation and soils, volcanic emissions, lightning, and sea salt)

• PM_2.5 from wildfires, road dust, and agriculture

• Volatile organic compounds (VOCs) from background biogenic sources (mainly vegetation)

NH₃ and NO₂ emissions reductions would likely be difficult to achieve without changing agricultural production or practices. Moreover, biogenic and wildfire sources of pollutants will remain, and wildfire frequency may increase with climate change. Road dust PM_2.5 also exists with both internal combustion engine and electric vehicles. Reducing pollutant emissions in the sectors listed above might yield further health benefits beyond those represented in this analysis.

Racial-ethnic minorities are disproportionately exposed to fine particulate matter in the United States.

While the NZNW Health Impacts analysis does not model health outcomes for specific demographics, understanding unequal exposure to air pollution and PM_2.5 is critically important. Exposure to particulate matter varies based on proximity to emission sources, such as industrial facilities, construction sites, and highways with high concentrations of gasoline and heavy-duty diesel vehicles.

Due to the legacy of unequal and unjust housing policies, as well as other factors, exposure disparities exist for people of color in the United States. Despite an overall trend toward cleaner air quality, nationally people of color are exposed to 14% higher levels of PM_2.5 than the population average and 25% higher than white people.

Nationwide patterns in air pollution inequity largely hold true for the Northwest as well. Across the region, air pollution exposure is lower than the national average, but exposure disparities persist. In Washington, Oregon, and Idaho, most major sources of air pollution disproportionately impact people of color. Montana is an exception, where air pollution exposure tends to be much lower overall than in other states.

Conclusion

The health benefits and related cost savings that result from reducing smokestack and tailpipe emissions provide support to the climate benefits for achieving net-zero emissions by 2050. If optimizing for air quality rather than meeting greenhouse gas emissions targets, a state could employ different strategies to further reduce pollutant emissions. Furthermore, greenhouse gas reductions beyond net-zero could be cost-effective if health outcomes and their economic benefits are included.