Dirty Air


Steam billows from a power plant smokestack.


Clean air should be a top priority for the U.S. Environmental Protection Agency (EPA). But the agency is ignoring the science yet again, putting human health and water quality at risk by refusing to strengthen standards for particulate matter pollution.

A recurring theme has emerged at the Trump administration's EPA—ignore the science and put human health at risk. In addition to the agency’s proposals to restrict the types of science it considers, undermine standards that limit emissions of mercury and other toxic pollutants, roll back emissions standards for cars, and limit public input in decision-making processes, EPA now plans to ignore experts telling the agency that particulate matter is dangerous to human health and should be regulated more strictly.  

Problematic Particles

Particulate matter is an air pollutant that harms human health and the environment. 

Emissions of particulate matter can be thought of in two major categories:

  • Primary particulates come directly from human and natural activities, such as dust from storms, and materials emitted from industrial sources, such as soot from coal-fired power plants.
  • Secondary particulates develop from chemical reactions that happen when emissions of precursor gases enter the atmosphere. Precursor gases include sulfur dioxide (SO2) emitted from power plant and industrial facilities, nitrogen oxides (NOx) from power plants and vehicles, and ammonia (NH3) from poultry and livestock operations. 

Scientists have concluded that when inhaled, particulate matter is linked to asthma, bronchitis, lung cancer, heart attacks, and premature death. The finest particulates, known as PM2.5, are finer than a single strand of human hair and pose the greatest risk to human health because they can penetrate deeper into the lung. 

Particulate matter, especially secondary particulates derived from precursor gases that carry nitrogen molecules, can also harm water quality because it contributes to nitrogen pollution. In fact, air pollution accounts for roughly one-third of the nitrogen pollution in the Chesapeake Bay. The nitrogen feeds excessive algae growth, leading to oxygen depletion and fish kills when the algae dies and decomposes.

Protecting Public Health

The Clean Air Act requires EPA to set National Ambient Air Quality Standards (NAAQS), including standards for particulate matter, at a level necessary to protect public health and public welfare based on the latest scientific knowledge

A large body of public health scientific evidence suggests that particulate matter standards should be lowered, at a minimum, to between 8-10 micrograms per cubic meter of air. Despite this, EPA has proposed to retain the current standards that were set in 2012 at 12 micrograms per cubic meter of air.

When making the decision to not change the standards, EPA ignored scientific expertise. It drafted its decision to not change the standards before it even finalized its scientific assessment, and the agency disbanded its own advisory committee, which had critical information about the impact of particulate matter pollution on the health of individuals across the country.

Moreover, EPA is rushing the decision through—providing a short 60-day public comment period—during a global pandemic. This is particularly concerning given the links between particulate matter and respiratory illnesses. The spread of COVID-19 has shown how poor air quality in overburdened industrial communities has rendered residents more susceptible to the virus than their counterparts in less polluted areas. Recent studies have found a correlation between PM2.5 exposure and contraction of the coronavirus. 

As we have seen with many of EPA’s actions recently, the agency is abandoning its responsibilities in favor of corporate development and using COVID-19 as an excuse to expedite these efforts. This puts us all at risk and is particularly damaging for those living in communities that are already overburdened by pollution. 

The Risk to Bay Residents

For a variety of reasons, those living and working in the Chesapeake Bay Watershed are particularly impacted by particulate matter pollution. For one, the region is growing and seeing an increase in sources of particulate matter, such as natural gas projects throughout Virginia that emit particulate matter. 

In many cases, when state regulators review industrial facilities for approval or permit adjustments, they look to federal standards as a compass for their decisions. This latest move by the Trump administration would leave communities throughout the watershed without the protections they so desperately need. Communities facing environmental injustices are especially susceptible to particulate matter pollution, and this decision to not strengthen the standards will continue to place a disproportionate harm on them.  

Two cases illustrate how this is playing out in the Bay watershed: 

In Charles City County, Virginia, two natural gas-fired power plants have recently received permits from the Virginia State Air Pollution Control Board and are now slated for construction. The Chickahominy Power Station and the C4GT Plant are proposed to be sited approximately one mile away from each other and will emit PM2.5 as part of their operations. Charles City County is predominantly African American and economically marginalized, yet these facilities continue to be approved by state regulators who are citing the federal government’s standards as support for their decisions. 

In order to support the impending operations of C4GT, Virginia Natural Gas, Inc. has proposed a six part “Header Improvement Project” which would include the construction of two compressor stations and the expansion of another. A portion of the proposed pipeline will run through Charles City County, and one of the three proposed compressor stations will be located in Chesapeake, another predominantly African American and economically marginalized community. The compressor stations, like the one CBF advocated against in the landmark Friends of Buckingham case, will emit PM2.5.

In Baltimore City, Maryland, the Wheelabrator trash incinerator burns the majority of the city’s garbage and is the city’s single largest source of industrial air pollution. The plant, whose smokestacks rise above I-95 near the Baltimore sports stadiums, also burns trash from Anne Arundel and Howard counties. In 2016, the plant produced about 1,100 tons of nitrogen oxides (NOx), which contribute to particulate matter in the form of smog, a respiratory irritant. Fine particles from the smokestack’s emissions also travel beyond Baltimore, causing an estimated $55 million annually in health problems. And when it falls into the waters of the Bay, NOx and other forms of nitrogen trigger a chain reaction of algae growth, oxygen depletion, and fish kills. While the State of Maryland adopted regulatory changes in 2018 that would cut Wheelabrator emissions by approximately 200 tons a year, it is a helpful example to understand the harm particulate matter and its precursors can have on communities and the Bay.

CBF Is Holding EPA Accountable

CBF continues to keep a watchful eye on EPA’s decisions. Our work is focused on ensuring the goals of the Chesapeake Clean Water Blueprint are achieved by 2025. Rollbacks to important clean air standards and regulations will impact progress towards a saved Bay. We recently joined a coalition of environmental and health groups to submit comments to EPA on this important decision. We told EPA that particulate matter standards should be strengthened to adequately protect human health and the environment. 

Denise Stranko, Federal Legislative and Policy Manager

Issues in this Post

Air Pollution   Air Pollution   Environmental Justice  


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