The relationship between aviation activities and ultrafine particulate matter concentrations near a mid-sized airport

► Aircraft contribute to emissions of ultrafine particulate matter (UFP). ► We use monitoring data and flight activity to quantify UFP contributed by aircraft. ► Wind speed/direction and flight activity lag terms predict measured concentrations. ► Aircraft contribute 15-30% of UFP near-airport fenceline during operating hours. ► Regression models of continuous monitoring data can inform source attribution.