Growing up in the 1960’s in the suburban Washington, DC area, I suffered from asthma so there were days and nights when I thought I might be taking my last painfully wheezing breath. Certainly sucking in pollution did not make my condition better and made me more aware of the importance of clean air. The worst sources of pollution came from people burning leaves, trash, wood stoves, coal-fired power plants, gasoline and diesel fumes from vehicles and industry - all these were legal and common in my area and still are in many parts of the world. I’m one of 300 million people who suffer from asthma and while I’ve learned to control my symptoms, including where I choose to live, many people are not so fortunate.
In June 2019, I wrote a blog that doctors are prescribing clean air for our health and see the disease of toxic pollution getting worse. Over 70 groups signed a call to Climate Health Action.
University professors and government agencies are assisting medical professionals to evaluate the impacts of air pollution effects on human health. Global data sets combining air quality collected from NASA satellite are now available! These maps can help doctors, researchers and environmental justice advocates to evaluate air quality impacts from pollutants including small particles (PM2.5), nitrogen oxides (NOx), volatile organic compounds (VOCs) and ozone (O3).
What happens when a project is proposed and it won’t show up on current global datasets? For that we need to employ computer simulations to create models. This week, a neighbor and colleague shared his modeling predictions to the Apex Town Council on the proposed 300 megawatt data center that is the frequent subject of my blogging to raise awareness. Here’s his testimony:
“Good evening, Mayor Gilbert, members of the Apex Town Council and Town staff: My name is Sarav Arunachalam, a 26-year resident of Apex . I am a Chemical Engineer and Professor of Environmental Sciences and Engineering at UNC Chapel Hill. I am also Director of the Center for Environmental Modeling for Policy Development at the UNC Institute for the Environment.
I have studied emissions and air pollution for the past three decades and worked with multiple state agencies, industry and the U.S. EPA on various air quality issues. I have given expert testimony to the North Carolina Department of Justice, U.S. Department of Justice, and most recently to the U.S. Senate on U.S. methane-related air pollution and health. I am here to talk about the proposed 300 MW Data Center in New Hill, which among other impacts, will have onsite generators with excess emissions of multiple pollutants that will lead to dirty air, contaminated water and unhealthy citizens. Generating power for a 300 MW data center on-site is akin to having a polluting power plant in the town with its motto “Peak of Good Living”.
The state of North Carolina has been in attainment of the health-based standards for all criteria air pollutants for over a decade, except in 2023 when there were exceptional events due to smoke from the Canadian wildfires. When a region achieves all air pollutant standards, the citizens are healthy, millions of $ are saved due to avoided health costs, the economy grows and the skies are blue. However, when a region is designated nonattainment, and if the region/state doesn’t have a plan for emissions reductions to clean the air, various enforcement measures kick in. Besides increased health costs to the general public, the nonattainment region suffers on various fronts. Despite some considerations by the EPA (reported by NYT last month) not to look at savings in health costs for pollution controls per a recent proposal, the fact remains that when you avoid pollution, you save on health costs. With the proposed 300 MW data center in New Hill, we are at the risk of having excess emissions that will likely reverse over a decade of clean air that citizens of North Carolina have enjoyed. It is then likely for Wake County and its neighbors to show up in the dirty county list that the American Lung Association compiles each year.
These excess emissions are projected from both the proposed data center due to onsite generation of backup power, as well as from Duke Energy when Duke has to ramp up production to meet year-round energy demand on the grid including possibly extending the life of fossil-fuel based power plants. Just last week, when we had an invasion of Arctic air into the region, we saw that Duke made an appeal to the citizens of North Carolina to reduce its energy usage to help with increased energy demand. So many hyperscale data centers in other states were required to operate backup emergency diesel generators.
I will switch to a narrative on a tale of two Data Centers. In the first Data Center, the one proposed for New Hill, the onsite backup generators are expected to run for multiple hours over the period of a year for testing, and then for backup power for the Data Center should there be a power outage or emergency from Duke. Using a regulatory dispersion model developed and promulgated by the EPA, I have taken the liberty to model the air quality impacts of excess emissions of oxides of nitrogen (NOx) assuming that they will use diesel fuel.
While the generators can be fueled by any of diesel, natural gas or renewables, we have heard from the developer about the potential use of Tier 4 generators. While a Tier 4 generator is better than Tier 3, the potential still exists for using fossil fuel, and I will use that scenario here. There are two alternatives to having this backup power generation. A single large facility onsite with a tall stack or 100 smaller sources with likely identical capacity. I have provided a series of maps to help you walk through this modeling.
Figure 1 shows the prevailing direction of winds as are reported at the Raleigh-Durham international airport, which is representative for this region. As you will see, for 3 of the 4 seasons, the winds are blowing from the Southwesterly direction. However, during the Fall season, they are from the Northeast. I will show air quality impacts of NOx emissions ( one of the many pollutants emitted during diesel combustion) as footprints using contour plots.
Figure 2 shows incremental rings that are uniformly spaced by 1 km from the proposed facility on Shearon Harris Road. These rings intersect New Hill Olive Chapel Road at 2-km, 540 at 8-km and NC-55 at 11km downwind from the facility. [Note that I am discussing units in SI units, which is the norm mandated by the American Meteorological Society for atmospheric science calculations to promote consistency and standardization for comparison in global context]. I have also shown the locations of the vulnerable and sensitive populations - our children, by identifying locations of multiple schools and playgrounds in Apex. Figure 2 (right panel) also shows the alternate location of these 100 generators – laid out in a 10x10 array on the proposed property for this modeling study.
Figure 3 shows the annual average (on the left) and the single hourly maximum NOx concentrations (on the right) at each receptor at these radial distances. The annual average values are almost 1 µg/m3 at this location where we are right now, i.e., the Apex Town Hall, while the maximum single hour concentration exceeds 200 µg/m3 just outside the 1-km ring. We also see values of > 50 µg/m3 near the Apex Town Hall, over 11-km away from the facility.
Now, let us look at an alternate scenario where the proposed facility will have 100 smaller capacity (3MW) generators as is being proposed. Since these are much smaller in size, it is reasonable to assume that the emissions release height is lower than a single tall facility and hence the atmospheric dispersion will be relatively localized, i.e., higher impacts in the near-field.
In Figure 4, the annual average impacts are > 100 µg/m3 just over a km from the facility, and a larger plume of between 10 – 50 µg/m3 is seen in a roughly 10-km radius all around the facility. Correspondingly, the maximum single hour concentration values are in the several hundreds of µg/m3 range spread more like a pancake all around the facility over a 15 - 20 km radius, with the maximum impact being > 2,500 µg/m3 within the first 1 – 2 km from the facility. Comparing these predictions with the NAAQS for Nitrogen Dioxide (NO2), a primary component of NOx, at 188 µg/m3 (over 1 hour) and 100 µg/m3 (annually) indicates air quality levels would be exceeded by more than double a km away while the maximum impact is 250 times the current NO2 NAAQS designed to protect public health.
While the modeled impacts I presented are from oxides of nitrogen, these gases go on to form fine particulate matter, particles of size less than 2.5 microns (or micrometers) through various physical and chemical processes. A micrometer is 1 millionth of a meter. The 2.5 micron size is roughly 1/20 of the width of a human hair. Exposure to air pollution from fine particulate matter is the single largest global environmental health risk, with about 8M people dying prematurely each year. In the U.S. alone, that number is about 100,000 per year. Short-term exposure triggers acute symptoms, while long-term exposure increases chronic disease risk and mortality. Recent studies in the epidemiological literature have also shown impacts on pregnant women leading to premature birth, autism, and also cognitive decline, leading to increased risk for neurodegenerative diseases like Alzheimer’s.
So, in the town at the Peak of Good Living, you may have the vulnerable population – children and older adults being affected the most, not to mention healthy adults also showing new adverse symptoms due to exposure to this pollution from the first data center. Due to cognitive decline, it is possible that test scores of students of Southwestern Wake county and likely Chatham county are negatively affected.
To conclude, while there are several concerns related to the proposed data center - excess emissions that affect the quality of air we breathe, excess demand on water that will strain the local resources, excess noise that will affect sleep, excess costs to consumers due to higher electricity bills, the question that I implore you to ask yourselves is: Are there really any benefits in any form to the Town of Apex and its residents that exceed the cumulative costs due to the proposed Data Center?
Thank you for the opportunity to provide this testimonial, and for your time today.
I look forward to being back on a future date to talk about the 2nd Data Center to provide a contrast to the first one that I presented today.
I look forward to learning more about how to prevent sources of air pollution from Dr. Arunachalam as well as from other sources and understand for the 2nd Data Center he plans to speak about the new public library coming to our neighborhood in New Hill! Please let others know we do not want to live by industrial-sized data centers or other factories emitting air pollution.