Did you ever think that cooking could produce air pollution? I certainly didn’t at first, but it in fact does! Two specific types of air pollution are a concern here: PM2.5, which are super tiny particles within the air, and NOx, which is a gas. PM2.5 is produced pretty much anytime you are cooking, no matter if you are using a stove top, oven or a grill. NOx is a little bit more particular about when it is produced and really is only produced when using a cooking method involving a flame. This makes sense considering NOx is a biproduct of combustion, such as in our car engines. The major concern with both of these pollutants is that they can cause respiratory complications. A recent study has shown that areas of cities with high numbers of restaurants tend to have higher levels of these two pollutants.
Applying this to our college campus, we were curious as to how this translates to our campus. We had read a paper about how the air pollution from vape shops was entering neighboring businesses and we wondered if the pollutants from restaurants also traveled within buildings (as seen below). Thus, we wanted to see how the restaurants on campus were affecting the air quality within neighboring classrooms, as most of them are attached to lecture buildings and there could be a concern for the staff and students at USD. We only tested for PM2.5 and NOx as these are the pollutants known to be produced from cooking.
Our hypothesis was that PM2.5 would be very high next to the cooking areas of the restaurants and decrease as we moved our of the restaurants, but still remain at a level higher than the typical level for the building. The same goes for NOx, but only for restaurants that use cooking methods involving open flames.
In order to test this, we took 3 low-cost air quality sensors that anyone can purchase to measure air quality around them and went to 3 restaurants on campus: Aroma’s Cafe, Bert’s Cafe and Oliva. This is a very simple device and is constantly measuring both PM2.5 and NOx. We took 4 measurements at each location – in the restaurant next to the cooking area, the opposite side of the restaurant from the cooking area, in the hallway connecting the restaurant to the neighboring classroom, and within the neighboring classroom. For Bert’s Cafe and Oliva, a 5th measurement was added from the opposite side of the building in order to figure out the normal levels of these pollutants in each building.
From this data, we found that the concentration of PM2.5 was significantly higher than the concentration of NO2 near the cooking area throughout all three sites that were sampled. NO2 concentrations did generally increase the further we got from the cooking station at each restaurant. PM2.5 did not follow a specific pattern as at Aroma’s Cafe, the highest value was seen across from the cooking area, decreased as we moved away from the cooking area at Bert’s Cafe, and decreased and then increased again in the classroom next to Oliva. To see the graphed data, scroll to the end of this post.
In terms of NO2, the trend we did see and what we expected to see were exactly opposite. This is probably due to the fact that Oliva is the only restaurant sampled that uses an open-flame to prepare some of their food. Perhaps during the sampling at Oliva, the type of food cooked with this method was not ordered, so the grill wasn’t in use. The reasoning why they decreased could be due to a good ventilation system in each of the restaurants, which is pushing out any background NO2 from the building within each restaurant.
For PM2.5, our hypothesis was neither refuted or supported as the data is very different across the 3 restaurants. While the discrepancies could be due to the differences in cooking methods used at each location, they could also be due to errors in the measurements from our air quality sensors. If this is the case, then the NO2 data is up for question as well. I think in order to draw significant conclusions from this data, we would need to use a more high-tech air quality sensor to better ensure that our data is accurate. We also did not study all of the restaurants on campus, so that would also be important to see how our entire campus as a whole would be affected by these pollutants produced from cooking. This is especially important as some of the buildings containing the restaurants also have dorm rooms within them, meaning longer exposure for those students.
The good thing here is that it seems from the data we have that the pollutants from the restaurants are not causing a severe effect on the surrounding classrooms. 🙂
Figure 1. Averages of data collected with two Flow air quality sensors in Aroma’s Café and neighboring areas. All data was collected on September 26, 2024.
Figure 2. Averages of data collected with three Flow air quality sensors in Bert’s Bistro and neighboring areas. All data was collected on October 2, 2024.
Figure 3. Averages of data collected with three Flow air quality sensors in Oliva and neighboring areas. All data was collected on October 9, 2024.
Sources:
Li, Liqiao, et al. “Impacts of Electronic Cigarettes Usage on Air Quality of Vape Shops and Their Nearby Areas.” Science of The Total Environment 760 (2021): 143423. Print.