Letter to the Editor

Impact of Va's proposed waiver of air pollution controls to allow for sustained diesel generation supply to northern Virginia Data Centers

The Counsel to the National Wildlife Federation explains the dangerous of air pollution from diesel generators


It is hard to imagine the amount of dangerous air pollution that would occur if, one day, all of Virginia was suddenly powered by diesel fuel. That could never happen, right?  Wrong.  That is exactly the trajectory Virginia is on because of industrial data center development in the northern part of the state.

Between Loudoun and Prince William County, there are already 40 million square feet of data centers in operation handling some 40% of the world’s Internet traffic and storage. Each individual data center burns enough electricity to power 40,000 to 80,000 homes. Virginia now has 100 of them. And, there are at least 60 million more square feet of data centers (another 150 centers) being built or being approved, mostly in Prince William County. The power draw from all of these centers, once on line, will be the equivalent doubling current electricity demand for the entire State of Virginia. For reference, this would be four New Hampshires or two Marylands worth of power just for Virginia data centers.

Now imagine them all running on diesel fuel for days at a time.  Impossible right?  Wrong again. A new proposed State of Virginia air pollution control waiver would not only make this possible, but would actually require data centers to run on diesel backup generators during periods when the state’s power grid is being overtaxed by the usual sources. This happens often during summer heat waves and winter cold spells. It will happen more when data centers are feeding from the power grid.

The pollution impact on the northern Virginia region, the Chesapeake Bay and Loudoun and Prince William County residents, in particular, could be life-threatening for many, particularly the elderly, children with asthma, and people living in lower-income communities. It is an environmental justice issue of the first order brought to you by a County Board that claims that fighting environmental injustices is a priority.

For northern Virginia, this would be like moving tens of thousands of diesel trucks into the region, parking them and letting them run day and night.  The average back-up diesel generator for a data center puts out 1.5 to 3.0 megawatts and the average data center has six to 12 of these behemouths.  There would be thousands of them running in Loudoun and Prince William. 

In recent years, studies have found that diesel engines are emitting much more air pollution than previously thought. It means that the amount of harm done to people is higher than previously estimated as well. Using a variety of data sources including observations from NASA satellites, research teams have concluded that diesel emissions caused around 38,000 early deaths in the U.S. in 2015, for example, well above previous estimates. Moreover, Heavy duty diesel engines emit significant levels of nitrogen oxides (NOx) which can be a severe problem for urban neighborhoods. NOx is particularly dangerous as it is both a pollutant itself and a precursor chemical leading to the creation of fine particulate and ground-level ozone pollution. Exposure to NOx pollution has been shown to inflict a number of respiratory health issues over both short- and long-term exposure, including reduced lung function and inflammation.

Public health officials note that Diesel air pollution irritates the nose, eyes, throat, and lungs. It can cause coughing, headaches, nausea, and lightheadedness. The effects, as noted, are more pronounced in those who are more susceptible to pollutants, like those with severe allergies, asthma, and other pre-existing conditions. Those exposed to diesel exhaust over long periods of time are more likely to develop lung cancer or other cardiovascular diseases. Indeed the U.S. EPA states that exposure to diesel exhaust can lead to serious health conditions like asthma and respiratory illnesses and can worsen existing heart and lung disease, especially in children and the elderly.  These conditions can result in increased numbers of emergency room visits, hospital admissions, absences from work and school, and premature deaths.

Numerous major public health studies bear this out starting with reference to death rates. For example, a study by Harvard University School of Public Health, in collaboration with the University of Birmingham, the University of Leicester and University College London, found that more than 8 million people globally died in 2018 from fossil fuel pollution. This was significantly higher than previous research suggested—meaning that air pollution from burning fossil fuels like coal and diesel was responsible for about 1 in 5 deaths worldwide. Worldwide, air pollution from burning fossil fuels is responsible for about 1 in 5 deaths—roughly the population of New York City each year.

The U.S. EPA has found that diesel exhaust, in particular, contains dozens of toxic substances but one of the leading concerns is the particulate matter which is toxic and very small in size at less than 2.5 microns. A typical human hair is 70 microns. The small size makes it highly breathable to the deepest part of the lungs. These ultra-fine particles are also known to attract other toxic substances in the air, thus increasing toxicity.

In another study of more than 4.5 million U.S. military veterans, nine causes of death were associated with fossil fuel particulate matter air pollution.  These included cardiovascular disease, cerebrovascular disease, chronic kidney disease, chronic obstructive pulmonary disease, dementia, type 2 diabetes, hypertension, lung cancer, and pneumonia. The attributable burden of death associated with diesel and fossil fuel particulate matter pollution was disproportionally borne by black individuals and socioeconomically disadvantaged communities;

There are cancer risks too.  The International Association for Research on Cancer classified diesel exhaust as a known carcinogen to humans. The new classification is based on sufficient evidence that exposure to diesel engine exhaust is associated with increased lung cancer risk.

As the State of Virginia considers waiving air pollution controls on diesel generators to provide operating security to the big tech companies, it needs to ask and resolve some key questions before making Prince William, Loudoun and surrounding counties the epicenter of diesel pollution:

  • Should the pace of rampant data center development in Northern Virginia be slowed to provide more time for a more careful approach to energy supply from less polluting means?
  • Is Virginia prepared to conduct basic public health, risk and vulnerability assessments of impacts on northern Virginia residents, prior to waiving the pollution controls, particularly for neighborhoods close to data centers? Or will these assessment also be “waived” at the expense of private citizens over big tech companies?
  • Is Virginia prepared to increase public health costs and pressure on people via increased rates of mortality, cancer, asthma, heart disease and other documented impacts of diesel pollution in favor of concentrating data centers in Loudoun and Prince William neighborhoods? 
  • Will northern Virginia community sitting down-wind from the data centers in Loudoun and Prince William Counties be prepared to receive the astounding amount of air pollution that will generated from running diesel engines for prolonged periods?
  • Will Virginia also assess and put limits on the noise impact of running large diesel generators at centers near homes, schools, businesses and public facilities?

Before proceeding, the State of Virginia and DEQ  and the Department of Public Health must carefully and reasonably address these concerns or it will create and combined energy and public health crisis.    


Kevin J. Coyle, JD

Counsel to the President and CEO

National Wildlife Federation


Uniting all Americans to ensure wildlife thrive in a rapidly changing world

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