Lichen are a cross between fungi and algae and due to their ability to absorb heavy pollutants, they are prime indicators of the air quality of their environment. We collected publicly available research-grade observations of common lichens on iNaturalist taken between Jan 1, 2018 and Dec 31, 2022. Then, the lichen population was compared to the air quality index, specifically PM2.5, to assess a correlation. A regression test was used to establish if any type of relationship exist and its significance. Ultimately, our data was inconclusive, with no consistent correlation between PM2.5 and the percentage of lichen observations over time across different lags. Considering several limitations, we believe that an investigation over a greater time frame is needed to observe a strong negative correlation between lichen population and PM2.5.