Nav: Home

People of color exposed to more pollution from cars, trucks, power plants over 10 years

September 14, 2017

A new nationwide study finds that the U.S. made little progress from 2000 to 2010 in reducing relative disparities between people of color and whites in exposure to harmful air pollution emitted by cars, trucks and other combustion sources.

The groundbreaking study led by University of Washington researchers estimated exposure to outdoor concentrations of a transportation-related pollutant -- nitrogen dioxide (NO2) -- in both 2000 and 2010, based on neighborhoods where people live. It found disparities in NO2 exposure were larger by race and ethnicity than by income, age or education, and that those inequities persisted across the decade.

While absolute differences in exposure to the air pollutant dropped noticeably during that time period for all populations, the relative difference -- or the gap between pollution levels to which white people and people of color were exposed -- narrowed only a little.

The study will be published Sept. 14 Environmental Health Perspectives. The researchers developed a first-of-its-kind model that combines satellite and regulatory measurements with land use data to predict pollution at a neighborhood level throughout the United States.

The positive news is that across the U.S., average exposure to NO2 for all races and income levels dropped from 2000 to 2010. Measured in parts per billion (ppb), estimated average annual NO2 exposure decreased from 17.6 to 10.7 ppb for nonwhite populations, and from 12.6 to 7.8 ppb for white populations.

Yet people of color were consistently exposed to more air pollution than their white non-Hispanic counterparts during the decade. Considering relative differences, nonwhites experienced 40 percent higher exposures than whites in 2000; in 2010, that gap shrunk only slightly, to 37 percent. Furthermore, in 2000, concentrations of NO2 in neighborhoods with the highest proportion of nonwhite residents were 2.5 times higher than in neighborhoods with the lowest proportion of nonwhite residents. In 2010, that value increased slightly, to 2.7 times higher.

The study concludes that if people of color had breathed the lower NO2 levels experienced by whites in 2010, it would have prevented an estimated 5,000 premature deaths from heart disease among the nonwhite group.

"The finding that shocks us is that when it comes to how much NO2 a person breathes, it's still race that matters," said senior author Julian Marshall, UW professor of civil and environmental engineering.

"At any income level -- low to medium to high -- there's a persistent gap by race, which is completely indefensible. It says a lot about how segregated neighborhoods still are and how things are segregated," Marshall said.

NO2 comes from sources such as vehicle exhaust, power plants and off-road equipment and is one of six important "criteria air pollutants" monitored by the Environmental Protection Agency. It has been linked to asthma symptoms, increased susceptibility to respiratory problems and heart disease.

The research team, which began their work at the University of Minnesota, previously analyzed NO2 concentrations for the year 2006 by race, income and other demographic factors identified in the U.S. Census. The team's air pollution model, which combines existing EPA air quality monitoring and satellite data with detailed land use information, allows them to accurately predict pollution concentrations across the country at the U.S. Census block level -- information previously unavailable at that scale.

In this first longitudinal study of its kind, researchers wanted to examine how much progress was made in addressing inequities in NO2 exposure over a decade. They compared environmental injustice metrics in 2000 and 2010 on a national basis and by region, state, county and urban areas.

On the whole, researchers said, policies to reduce NO2 air pollution are working. But the finding that exposure differences are larger by race and ethnicity than by income, age or education was equally true in 2010 as in 2000.

"Everyone benefited from clean air regulations and less pollution; that's the good news," said lead author and UW civil and environmental engineering doctoral student Lara Clark. "But the fact that there is a pervasive gap in exposure to NO2 by race -- and that the relative gap was more or less preserved over a decade -- is the bad news."

The UW study did not explore the underlying reasons for that gap, but its findings are consistent with previous research. Both racial minorities and low-income households are disproportionately likely to live near a major road where transportation-related pollution is typically highest. U.S. cities, in general, also tend to be more segregated by race and ethnicity than by income.

The UW team did conclude that the narrowing of the racial gap in NO2 exposures was driven more by improving air quality than by demographic changes over the 10-year period.

"That suggests that air pollution is coming down faster than cities are becoming less segregated," Marshall said.

Next steps for the research team include looking at how changes in demographics, industry and urban form at the city level affect NO2 exposure, and developing similar models for other EPA criteria air pollutants.

-end-

The study was co-authored by Dylan B. Millet, professor in the University of Minnesota's Department of Soil, Water and Climate.

The research was funded by the National Science Foundation and the Environmental Protection Agency.

For more information, contact Marshall at jdmarsh@uw.edu or Clark at lpclark@uw.edu.

University of Washington

Related Air Pollution Articles:

Air pollution may disrupt sleep
High levels of air pollution over time may get in the way of a good night's sleep, according to new research presented at the ATS 2017 International Conference.
Smoking out sources of in-home air pollution
An ambitious study led by San Diego State University researchers has investigated various factors that contribute to air pollution inside the house.
Cities need to 'green up' to reduce the impact of air pollution
The harmful impact of urban air pollution could be combated by strategically placing low hedges along roads in a built-up environment of cities instead of taller trees, a new study has found.
Study measures air pollution increase attributable to air conditioning
A new University of Wisconsin-Madison study shows that the electricity production associated with air conditioning causes emissions of sulfur dioxide, nitrogen oxides and carbon dioxide to increase by hundreds to thousands of metric tons, or 3 to 4 percent per degree Celsius (or 1.8 degrees Fahrenheit).
Air pollution may lead to dementia in older women
Tiny air pollution particles -- the type that mainly comes from power plants and automobiles -- may greatly increase the chance of dementia, including Alzheimer's disease.
Where is heavy air pollution in Beijing from?
The heavy haze formation in Beijing is depicted as 'initiated by the regional transport mainly from the coal burning in surrounding areas, and intensified by the local secondary formation originated from the motor vehicles.'
Future PM2.5 air pollution over China
There is a long way to go to mitigate future PM2.5 pollution in China based on the emission scenarios.
Salty snow could affect air pollution in the Arctic
In pictures, the Arctic appears pristine and timeless with its barren lands and icy landscape.
Diabetes: Risk factor air pollution
Exposure to air pollution at the place of residence increases the risk of developing insulin resistance as a pre-diabetic state of type 2 diabetes.
Air pollution exposure may worsen lupus in children
The results of a study presented today at the European League Against Rheumatism Annual Congress (EULAR 2016) show for the first time that an individual's exposure to air pollution may have a direct role in triggering disease activity as well as airway inflammation in children and adolescents with systemic lupus erythematosus.

Best Science Podcasts 2017

We have hand picked the best science podcasts for 2017. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: Radiolab

Radiolab Presents: Anna in Somalia
This week, we are presenting a story from NPR foreign correspondent Gregory Warner and his new globe-trotting podcast Rough Translation. Mohammed was having the best six months of his life - working a job he loved, making mixtapes for his sweetheart - when the communist Somali regime perp-walked him out of his own home, and sentenced him to a lifetime of solitary confinement.  With only concrete walls and cockroaches to keep him company, Mohammed felt miserable, alone, despondent.  But then one day, eight months into his sentence, he heard a whisper, a whisper that would open up a portal to - of all places and times - 19th century Russia, and that would teach him how to live and love again. 
Now Playing: TED Radio Hour

Future Consequences
From data collection to gene editing to AI, what we once considered science fiction is now becoming reality. This hour, TED speakers explore the future consequences of our present actions. Guests include designer Anab Jain, futurist Juan Enriquez, biologist Paul Knoepfler, and neuroscientist and philosopher Sam Harris.