Air Quality at Georgia Tech
By John Schmidt, Office of Sustainability Student Assistant, Computer Science ’25
Why is air quality important?
When tracking emissions, carbon dioxide (CO2) and other greenhouse gases (GHGs) are often given the most attention, and rightfully so; finding ways to reduce GHG emissions is essential for avoiding the most harmful effects of climate change. At the same time, many of the same activities that produce GHGs also produce air pollutants that can be harmful to human health. For example, internal combustion engine vehicles produce tailpipe emissions in addition to the tire and brake wear that all vehicles generate. Burning fossil fuels like natural gas or propane also emits harmful pollutants, and Georgia Tech – like most universities – relies on these fuels for transportation, generating electricity, and heating or cooling campus buildings. Air pollutants have long been shown to cause premature deaths along with harmful effects on the cardiovascular and respiratory system (https://www.epa.gov/clean-air-act-overview/air-pollution-current-and-future-challenges), so measuring and aiming to reduce these pollutants is important for the health of the entire Georgia Tech community and its surroundings.
Air Monitoring
Monitoring air quality can be difficult, however, primarily because professional grade equipment is expensive. While low-cost sensors are becoming more and more prevalent, they tend to only monitor for a few common pollutants, and their accuracy can be affected by a variety of external factors, including weather. Georgia Tech does have a regulatory ambient air sensor on campus managed by the Georgia Department of Natural Resources (https://gispub.epa.gov/airnow/) which sends data to the Environmental Protection Agency (EPA) as part of its AirNow data collection and forecasting program. The data from that sensor is publicly accessible and a source of highly accurate data. Monitoring air quality with physical sensors comes with one huge disadvantage though: there’s no way to quantify where the pollutants are coming from.
Ambient (outdoor) air quality can be affected by any number of sources, some of which may not be caused by human activity or located nearby. Weather conditions including wind, pressure, and humidity; distant wildfires producing huge quantities of smoke; and dust or wind erosion are a few examples. As an Institute that does emit air pollutants, this presents a problem for trying to measure the impact we make through direct air measurement. Instead, we can take an inventory of activities that are significant sources of air pollutants and make estimates utilizing our Greenhouse Gas Inventory. By collecting data on usage and relying on published emissions factors from groups like the Environmental Protection Agency (EPA), we can get a better sense of how activities on campus may be impacting the air quality (and thus health) of our community.
Georgia Tech's Pollutants
Visualization of Air Pollutants measured in pounds (lbs) by the air quality inventory of FY 2023
We classify the pollutants in our inventory into two groups, each with sub-categories:
1. On-Campus pollutants (gold)
• Major Stationary Sources
-Natural gas boilers used for heating campus
• Mobile Sources
-Institute-owned fleet vehicles
-Stinger Buses
2. Off-Campus pollutants (blue)
• Off-site electricity production
-Driven by Georgia Power’s energy mix, see figure below
• Commuting
In general, Off-Campus pollutants make up a larger portion of total emissions and are affected by infrastructure and policies outside of the Institute. For this reason, we focus our analysis on the On-Campus sources, where Georgia Tech has more control over reducing air pollutants.
Georgia Power’s Energy Mix
Georgia Power Energy Mix, 2023: While changing every year, the electricity that Georgia Tech currently uses combusts fossil fuels like natural gas and coal during generation. Electrifying campus fleet vehicles and heating systems will still reduce emissions and pollutants, and those reductions grow as Georgia Power’s energy mix increases its percentage of renewable energy.
We can further separate the On-Campus sources into their respective share of pollutants. The four pollutants we focus on are:
Carbon Monoxide
Carbon Monoxide (CO) constitutes a large portion of tailpipe pollutants and is generally released whenever something is combusted. Due in large part to stricter emissions standards, ambient amounts of CO have largely fallen to levels that are not seen as harmful to most people or the environment, though elevated levels can still be problematic for individuals with heart disease. Indoor levels can be very dangerous and need to be monitored.
Particulate Matter
Particulate Matter (PM) is a broader category of all airborne particles falling into the <2.5 ug or <10 ug categories (referred to as PM 2.5 or PM 10). Many air monitors only measure these particles because of their strong relation to negative health effects and their utility as an aggregate measure of different pollutant types. Primary sources of PM include smoke, dust, and power plants. Many types of pollutants, including Sulfur Oxides (Sox) and NOx, also react with other compounds in the air to create PM and are referred to as a secondary source of the pollutant category.
Nitrogen Oxides
Nitrogen Oxides (NOx) constitute the largest share of pollutants on campus by a significant margin. NOx comes from Major Stationary Sources, as NO2 is a primary output from burning many fossil fuels. It can cause a variety of negative health effects on the human respiratory system.
Sulfur Oxides
Sulfur Oxides (SOx) are typically emitted by power plants and large industrial facilities. They can have negative respiratory effects on humans and can cause damage to ecosystems.
Visualization of On-Campus Air Pollutants measured in lbs. and split into shares of Pollutant type
Reducing Pollutants with the Climate Action Plan
Georgia Tech’s Climate Action Plan, published in 2024, provides concrete strategies to cut GHG emissions and integrate climate education, advance climate research, and ensure equitable, cost-effective solutions. While the plan specifically highlights air quality improvement as part of the Mobility strategy, considering the significant correlation between greenhouse gas emissions and air pollution, many of the other CAP goals will also substantially reduce the amount of pollutants emitted on campus. Goals 1.1 and 3.1, for instance, call for transitioning both combustion-based heating systems and the campus vehicle fleet to electrified, zero-emissions sources. Doing so would eliminate the largest emitters of on-campus air pollutants in natural gas boilers and internal combustion engines, with the potential to reduce mobile source pollutants by 96% and major stationary pollutants by 100%*. There are also goals that can help reduce the Off-Campus pollutants. Goals 2.1 and 2.3 call for increasing onsite renewables and purchasing electricity from zero-emissions sources, and goal 3.2 aims to increase commuting options that are more affordable and more sustainable.
*Note that, assuming the same energy mix, some of this share of pollutants shifts to off-site electricity production as campus energy demand increases.
1.1 Transition to electrification of combustion-based heating systems
2.1 Increase onsite renewable energy production
2.3 Procure electricity generated from renewable and zero-emissions sources
3.1 Transition the campus vehicle fleet to zero-emission vehicles and equipment
3.2 Increase sustainable and affordable commuting options
Limitations
Because of limited data and because the scope of this work was significantly smaller than GHG inventory efforts, some air pollutant sources are not captured as part of this report. Results here should not be considered conclusive or exhaustive; rather, consider this a starting point for identifying ways to make our campus greener and healthier.
