Aircraft Activities and Ultrafine Particle Concentrations near a City Airport: Insights from a Measurement Campaign in Toronto, Canada

This study investigates the relationship between aircraft activities and ultrafine particle (UFP) concentrations near a regional airport in Toronto, Canada, positioned within a mile southwest of a densely populated downtown neighborhood. The analysis particularly considers the effect of the southerly winds on the UFP emissions from the airport. To achieve this, we conducted a measurement campaign at five locations between June 2022 and August 2022. Concurrently, detailed aircraft activity data were collected. Turboprop and propeller aircraft were the predominant categories. Results indicate a 20% increase in mean UFP levels north of the airport when winds originated from the south or southwest, coinciding with aircraft predominantly taking off eastward and landing westward on the runway. Smaller, older aircraft, often used for flight training and corporate travel, significantly contributed to UFP spikes, surpassing 50000 particles/cm3. In contrast, the prevalent large commercial aircraft had a lesser impact on UFP spikes. Airport activities are the primary source of UFP in the neighborhood. Under southerly winds, at the Ferry Terminal near the airport, diesel ferry operations, background UFP levels, and airport activities contributed 8%, 32%, and 60% of UFP concentrations, respectively.