Recently, our group conducted a study that looked at the presence of PM2.5 and NO2 inside on-campus restaurants and neighboring indoor areas. PM2.5 and NO2 are pollutants that are produced through the process of cooking food. Prolonged exposure to these pollutants can cause breathing issues in humans such as an increased risk of asthma, respiratory infections, and bronchitis. Exposure in small quantities for short periods of time tends to have no impact on us, but if these pollutants are making their way into neighboring classrooms where students and professors spend long periods of time, this could prove to be problematic.

https://www.sciencedirect.com/science/article/pii/S0048969720369540

Our hypothesis was that classrooms and spaces in buildings that neighbor on-campus restaurants will have higher concentrations of PM2.5 and NO2 than areas of a building that do not neighbor on-campus restaurants. This focuses on the search for a presence of NO2 and PM2.5 in spaces other than the immediate vicinity of a restaurant, and what the quantities of these pollutants are. Finding these answers would indicate a connection between the air circulation systems and the transportation of these pollutants.

In order to test this hypothesis, we established a procedure so that we would collect data from different buildings in the exact same way. This ensures that we minimize human error and collect reliable data. First we exposed three air quality sensors, which measured the amount of NO2 and PM2.5 present in the air, to a nitrogen chamber. A nitrogen chamber pushes pure nitrogen at a fast rate past the sensor so that the sensor is in a clean environment without pollution. We left the sensors in this chamber for fifteen minutes undisturbed, making sure that the sensors read zero for all amounts of pollution. This gave us a baseline to compare the rest of our data to later on. Once this was completed, the three air quality sensors were set up close to the cooking area of the chosen restaurant and left there for fifteen minutes undisturbed so that they could collect data on how much NO2 and PM2.5 were in the air. After the fifteen minutes we moved the sensors to another location in the same restaurant, but as far from the cooking area as possible to see how much the pollutants moved within the restaurant. They were left there for fifteen minutes undisturbed again, then moved three more times to three new locations: a classroom or common room close to the restaurant, the hallway that connected this room to the restaurant, and a location on the opposite side of the building. That last location was chosen so that we would have an indicator of what air was like in the building where there was no possible affect from the restaurant. This experiment was conducted in three different restaurants – Aromas Café, Bert’s Bistro, and Oliva – over the span of three weeks.

One of the main findings from our study was that the amount of PM2.5 was significantly higher than the concentration of NO2 in restaurants, while NO2 was more prominent in neighboring areas than PM2.5. The highest amounts of PM2.5 and NO2 were both found in Bert’s Bistro, while the lowest amount of PM2.5 was found in the stairway of Oliva and the lowest NO2 was found near the griddle in Aroma’s Café. A general trend was found for the NO2 concentrations, which was that the amount increased as distance from the restaurants increased. The other main finding was that there was a presence of both pollutants in neighboring areas such as hallways and classrooms close to restaurants.

While there were no clear cut answers to our hypothesis, a lot of important information was gathered that gives us a general idea of what happens to the pollution produced in restaurants. The movement of PM2.5 and NO2 from the restaurants to neighboring spaces inside the buildings and the fact that these concentrations were higher than in areas of the building far from the restaurants indicates that the shared ventilation systems may be the cause. This also provides us with a basis for future studies to focus on. Overall, the data supported the hypothesis that concentrations of the pollutants would be higher closer to the restaurant than on the opposite side of the respective building, but we were also left with some unanswered questions. The NO2 concentrations increasing as distance from the restaurants increased was not what we expected, as NO2 is generally produced in areas of cooking and combustion. This can be studied in future experiments to see why the concentrations are low near the cooking areas, and why higher amounts are found in other parts of the buildings.