A study in Science Magazine showed a correlation between higher levels of air pollution and lower standardized test scores in certain regions of China. Additionally, NO2 has been shown to cause mitochondrial dysfunction in rat brains, and another study links higher levels of it to a greater prevalence of Dementia and Parkinson's. Therefore, the goal of this research is to determine if NO2 gas can impact memory and learning.

To model the impact of NO2 on humans, apterous Drosophila melanogaster was used as a model organism because fruit flies are intelligent enough to be trained and have an airway system that shows physiological similarities to the lungs of mammals. The flies were exposed to NO2, at a constant low concentration, for 24 hours. To determine if the exposure had an impact on the flies' brains, the performance of exposed flies was compared to the performance of control flies in an olfactory appetitive training and testing assay.

First, preliminary experiments were run to test if the flies had an inherent preference for left or right or one of the odors. The flies showed no significant preference for left or right, but they did show a statistically significant preference for the 3-Octanol odor solution over the Benzaldehyde one. Their preference was accounted for in the data analysis of the main trials.

The next step was to train and test control groups of flies. Training was accomplished by first starving the flies for 20 hours and then repeatedly exposing them to one odor in conjunction with food and another odor by itself. The flies were meant to learn to associate one of the odors with food, and since they were starving, be motivated to move towards that odor during the testing.

During testing, flies were transferred to the intersection of two vials (one with each odor), and they were given 45 seconds to distribute themselves before being trapped in their vial of choice and counted. Analysis of the control data revealed that the flies statistically significantly learned to associate an odor with food. Across all trials, many more flies chose the odor they should associate with food than would be expected if training had failed.

The procedures for training and testing the NO2 exposed flies were exactly the same and started immediately after the flies had been exposed to the gas for 24 hours. Analysis of the testing data revealed that the NO2 exposed flies were not able to statistically significantly learn to associate an odor with food, unlike the control flies. Therefore, the research indicated that NO2 has a negative impact on memory and learning.

Further studies using lower concentrations of NO2 over longer exposure times to better simulate human exposure to NO2), other air pollutants, and model organisms more similar to humans are suggested to further investigate the possible impact of air pollution on human learning and memory.