Article by Molly Codding, MPH, Community Environmental Justice Coordinator | DNR – Urban and Community Forestry Program
While air quality in the United States has steadily improved since the Clean Air Act of 1990, air pollution is still a significant public health concern for environmental justice communities in Minnesota. In 2019, air pollution contributed to 4,000 deaths, 500 hospitalizations, and 800 emergency room visits annually (MDH, MPCA, 2020). Poor air quality results in an increased risk of lung cancer, asthma, ischemic heart disease, adverse pregnancy outcomes, and exacerbates circulatory and respiratory symptoms.
Our urban forest canopy removes many air pollutants, reducing some health risks related to poor air quality. U.S. urban park trees remove 75,000 tons of air pollution per year (worth $500 million). Studies have shown a lower prevalence of lung cancer, asthma rates for children, and reduced asthma hospitalizations during high pollution periods when the amount of air pollution removed or intercepted by trees is high compared to established air quality or health standards.
While overall air quality has improved, there are significant environmental justice concerns related to the relative disparities of many pollutant exposures by race-ethnicity. These concerns exist because of systemic land use and planning decisions surrounding transportation, the location of polluting facilities, the density of housing, and neighborhood segregation. For example, redlining policies (the discriminatory practice of denying home loans to persons of Color in geographic areas) resulted in highly segregated communities across the U.S. These segregated communities were often near industrial pollution permit sites, highway expansion projects, and historic disinvestment in public and private dollars.
In Minnesota, residents of the Twin Cities experience the lowest number of good air quality days, but recent smoke events have exposed northern Minnesota to increased numbers of unhealthy air quality days (MPCA, 2022). Air permits in the Twin Cities are concentrated in the eastern, central, and northern neighborhoods in Minneapolis and eastern St. Paul, which are historically segregated and low-income neighborhoods. The impact of inequitable pollution exposure has caused negative multigenerational impacts for Black, and Indigenous Persons of Color (BIPOC).
In cities across the country, previously redlined neighborhoods have fewer trees. Low-income communities and BIPOC communities have less access to canopy benefits, including improved air quality.
BIPOC and low-income communities experience greater rates of air pollution, including NO 2 . Between 2000 and 2010, BIPOC were more likely than white people to live in block groups with NO2 concentrations above World Health Organization health-based guidelines.
BIPOC communities experience higher rates of asthma, and Black men have a much higher prevalence of lung cancer than white populations. This is due to complex and interacting causes, including the proximity of historically segregated neighborhoods to pollution from industrial facilities and high traffic patterns. Reducing air pollution will both reduce harmful exposures to environmental justice communities and prevent environmental conditions that trigger asthma attacks, or increased breathing difficulty.
There are many ambitious tree planting initiatives, but the equitable distribution of tree canopy continues to be a challenge. Limited urban space to plant trees, barriers to planting on private property, lack of sustainable funding sources, and increased threats to existing canopy challenge the ability of cities to deliver equitable planting outcomes. Meanwhile, environmental justice communities are fighting for healthier neighborhoods, and their input on canopy priorities needs to be valued. More work needs to be done to support and elevate their efforts. The Department of Natural Resources is working with the U.S. Forest Service to coordinate Urban and Community Forestry resources with community groups, coalitions, and non-profits that are more closely connected to community-centered canopy priorities. Through stronger engagement with EJ communities, we can rewrite some of the harms caused by decades of systemic injustice so that they can realize the full health benefits of community forests, including cleaner air to breathe.
Image 1: Inequities in Canopy Cover for St. Paul
Caption: Several tools are available for assessing tree canopy equity for neighborhoods. American Forest’s Tree Equity Score highlights the canopy inequity trends experienced across urban areas nationwide. This tool takes into account percentage tree coverage, demographics including age, race, income, and community health indices to deliver a practical score for equitable community forestry planning.
American Forests: Tree Equity Score
Image 2: Air pollution in Minneapolis, MN
Caption: Minneapolis, and the Twin Cities metropolitan region experience the greatest number of poor air quality of days. The impacts of this pollution are felt by environmental justice communities, who also have poorer urban canopy coverage. Canopy equity initiatives can help mediate some of the disproportionate effects of poor air quality, in addition to providing shade, traffic and industrial noise pollution, and delivery of health ecosystem service benefits.