Exposure to microbes associated with soil and vegetation has been shown to stimulate the human immune system. However, less is known about aerial microbiota in cities. We are combining data from the PurpleAir citizen science air quality dataset with high-throughput sequencing of fungal spores from locations throughout San Francisco. Using kriged PM10 levels to characterize areas of differing air quality, we have identified sites that range in long-term average air quality between 17.5 and 27.5. The combination of these two datasets will allow us to understand their relationship with potential implications for human health.