Tiny particles of air pollution
contain more hazardous ingredients in non-white and low-income communities than
in affluent white ones, a new study shows.
The greater the concentration of
Hispanics, Asians, African Americans or poor residents in an area, the more
likely that potentially dangerous compounds such as vanadium, nitrates and zinc
are in the mix of fine particles they breathe. Latinos had the highest
exposures to the largest number of these ingredients, while whites generally
had the lowest.
The findings of the Yale
University research add to evidence of a widening racial and economic gap when
it comes to air pollution. Communities of color and those with low education
and high poverty and unemployment face greater health risks even if their air
quality meets federal health standards, according to the article published
online in the scientific journal Environmental Health Perspectives.
Los Angeles, Pittsburgh,
Cincinnati, St. Louis and Fresno are among the metropolitan areas with
unhealthful levels of fine particles and large concentrations of poor
minorities. More than 50 counties could exceed a new tighter health standard
for particulates proposed by the Environmental Protection Agency.
Communities of color and those
with low education and high poverty and unemployment may face greater health
risks even if their air quality meets federal health standards. A pervasive air
pollutant, the fine particulate matter known as PM2.5 is a mixture of emissions
from diesel engines, power plants, refineries and other sources of combustion.
Often called soot, the microscopic particles penetrate deep into the lungs.
The new study is the first to
reveal major racial and economic differences in exposures to specific particle
ingredients, some of which are linked to asthma, cardiovascular problems and
cancer. “Numerous studies indicate that some particles are more harmful than
others,” said lead author Michelle Bell, a professor of environmental health at
Yale’s School of Forestry and Environmental Studies.
The particles people breathe
include a variety of metals and chemicals, depending on their source. For
instance, people living near refineries are exposed to more nickel and
vanadium, while those near coal-fired power plants breathe particles with
higher sulfate content. Neighborhoods along busy roads have more nitrates from
vehicle exhaust.
One such community is Boyle
Heights, in East Los Angeles. It is more than 90 percent Hispanic and one
of the poorest parts of the city. Boyle Heights is “surrounded by
freeways,” said Susan Nakamura, planning manager for the region’s South Coast
Air Quality Management District, “and a lot of those freeways are used for
shipping commercial goods.” Four major rail yards emit diesel exhaust nearby,
and the area is home to “multiple auto body shops and chrome-platers in close
proximity to neighborhoods,” she said. She is especially concerned about the
particulate sources near schools.
A nationwide look
Bell and colleague Keita Ebisu
examined exposures to 14 components of particulates in 215 Census tracts
from 2000-2006. The components, including sulfate, a powerful respiratory
irritant, and nickel, a possible carcinogen, were chosen because they had been
associated with health impacts or accounted for a substantial amount of
particulates overall.
Census tracts with a greater
proportion of Hispanics had significantly higher levels of 11 substances.
Included is more than 1.5 times the whites’ exposure to nickel, nitrate,
silicon, vanadium – all linked in some studies to hospitalizations or deaths
from cardiovascular and lung disease – and aluminum, which is associated with
low birth weights.
Communities with larger
Asian populations had higher levels of seven components. Asians registered far
greater exposures than whites to nickel, nitrate and vanadium. And areas where
more African Americans lived showed significant elevations in four compounds,
including sulfate and zinc. People with less than a high-school education,
unemployed or living in poverty had more exposure to several components,
including silicon and zinc. Also, children and teenagers were more likely than
adults to breathe most of the substances.
The demographic differences raise
important policy questions, said Rachel Morello-Frosch, an associate professor
at the University of California, Berkeley, who studies the health risks of air
pollution but was not involved in the Yale study. Census tracts with a larger
proportion of Hispanics had significantly higher levels of 11 substances,
including more than 1.5 times the whites' exposures to nickel, nitrate,
silicon, vanadium and aluminum. She said targeted monitoring may be needed in
problem areas. “Then regulatory agencies may want to assess how they can
encourage emissions reductions from sources that are having localized impacts,”
Morello-Frosch said.
It’s a common scenario in cities
nationwide: Due to high housing costs and historical discrimination, low-income
and minority neighborhoods are clustered around industrial sites, truck routes,
ports and other air pollution hotspots.
In the South Bronx, a largely
Hispanic and African-American district of New York City, nearly four in 10 live
in poverty. Heavy traffic and a jumble of small industries taint the air with a
load of fine particles that frequently exceeds the federal health limit.
Asthma rates are as much as four
times higher in the Bronx than the national rates, said Dr. Norman Edelman,
chief medical officer for the American Lung Association. “They live near
highways, they live near where trucks spew diesel,” Edelman said. “That’s the
least desirable housing… much different than a nice, leafy suburb.”
And just south of Pittsburgh, a
slice of the Monongahela River Valley known as Liberty-Clairton tops the EPA
charts with the nation’s worst fine particle pollution outside of
California. Clairton, a mill town, is “home to the [U.S. Steel] Clairton Coke
Works, which is the largest coke-making facility in the nation,” said Rachel
Filippini, executive director of the environmental organization Group Against
Smog and Pollution. “The process of making coke is a pretty dirty one with lots
of particulates and air toxics.”
Tom Hoffman, Western Pennsylvania
director of the environmental group Clean Water Action, said childhood asthma
is rampant in Clairton, but a lot of families in the hardscrabble town don’t
have medical coverage. In some homes, the whole family shares a single inhaler,
he said.
Particulates are complicated
The health effects of fine
particle pollution are well-documented: Studies worldwide have shown that on
days when fine particle concentrations increase in a community, more people die
from heart attacks and respiratory problems. But far less is known about
whether specific types of particles translate to greater rates of illness or
death.
“Some of these particles are not
only composed of different things, but there are different gases and other
things that adhere to them on the outside. So they’re complicated in a whole
range of ways,” said Janice Nolen, author of the American Lung Association’s
annual State of the Air Report. Studies on the components are limited and have
given varying results. But some associations are clear. Sulfate, for instance,
can trigger asthma attacks, while vanadium irritates lungs, and nitrate causes
inflammation that may lead to heart attacks or strokes. Within cities, some
studies have found cardiovascular deaths rise with certain particles, including
nitrate, zinc, nickel, carbon, selenium and silicon.
More human research and animal
experiments are needed to understand which components are the most harmful and
why, said Marie Lynn Miranda, dean of University of Michigan’s School of
Natural Resources and Environment and director of the Children’s Environmental
Health Initiative. "They live near highways, they live near where trucks
spew diesel. That's the least desirable housing ... much different than a nice,
leafy suburb." -Dr. Norman Edelman, American Lung Association, speaking of
Hispanics and African Americans in the South Bronx“The notion of trying to
figure out what are the different components and are there specific things in the
PM2.5 that cause more of a problem… would have implications for how you
regulate health effects,” Miranda said.
The EPA earlier this year
proposed a more stringent health standard for fine particulate exposures that
will force new regulations in some cities. Its final decision is expected in
December. But the agency says too little is known about the specific
ingredients of the particles to set individual limits for them. “While
different chemical components of PM may have different effects on health, the
available scientific evidence to date supports setting standards that provide
protection against exposures to PM from all sources,” the EPA said in a
statement to EHN.
More racial disparities
The Yale study is part of a
growing body of research on racial and social disparities in air quality.
African Americans are considerably more likely to live in areas with the worst
levels of particulates and ozone, the main ingredient of smog, according to a
nationwide study by Miranda and colleagues. Hispanics and low-income residents
also are overrepresented in counties with high fine particle pollution.
Also, cancer risks from air
toxics such as benzene and formaldehyde are greatest in the nation’s highly
segregated metropolitan areas, according to research by UC Berkeley’s
Morello-Frosch and Bill Jesdale. The risks increase with degree of segregation
in all racial and ethnic groups, but are strongest for Hispanics, they found. “Our
question was: Are places that are more unequal disproportionately exposing
communities of color more than other groups?” Morello-Frosch said. “The answer
to that is ‘yes.’ Cities that are more segregated, you see higher pollution
burdens for residents of color.”
As for why Hispanics seem to be
facing some of the greatest air quality disparities, Morello-Frosch speculated
that it may partly reflect the “L.A. Effect.” “Because you have a lot of
Latinos living in one of the largest and most polluted cities in the United
States,” she said, “you might expect that contributing to the high population
burdens of pollution.” "Are places that are more unequal
disproportionately exposing communities of color more than other groups? The
answer to that is 'yes'."-Rachel Morello-Frosch, University of California,
BerkeleyMany questions about the effects of unequal exposures remain. Stress
from social and economic conditions seems to exacerbate the effects of
pollution, according to some recent research. In other words, the same amount
of pollution may harm poor people more than affluent people, or segregated
minorities more than whites.
“So if I’m exposed to air
pollution but I otherwise live in a pretty nice neighborhood, I don’t have a
very stressful life… how does that differ from, I’m exposed to air pollution
and I live in a cruddy house in a cruddy neighborhood and I have a very
stressful life?” Miranda asked. “How do the social factors in my life affect my
resiliency to environmental exposure?”
Source: New America
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