For the first time, researchers have analyzed outdoor PM10 from Milano Linate Airport and determined concentrations of benzothiazoles (BTHs), tire-related additives. The study, published in Environmental Chemistry and Ecotoxicology, reveals that these concentrations were much higher than those found in highly trafficked cities such as Milano and Collegno. Specific additives were proven to derive mostly from the airport area, with two of them strongly correlated, suggesting a close link to airport activities. The ecotoxicological assessment showed a low potential risk of occupational exposure to BTHs at Linate Airport.
The aviation sector plays a key role in worldwide connections, yet alongside its benefits, airports generate forms of pollution beyond exhaust gas emissions that are often underestimated: non-exhaust emissions, such as tire wear particles (TWPs). Produced during high-speed, high-friction events, TWPs are rubber particles that can easily enter the air, contributing to atmospheric particulate matter (PM) and carrying rubber chemical additives into the environment.
“Although TWPs can derive from all tire-equipped vehicles, they might pose a higher risk at airports considering the large amount produced especially during landings and takeoffs,” said Prof. Andrea Gambaro, senior author of the study. “So far, airport non-exhaust emissions are still poorly studied, leaving a huge knowledge gap.”
The researchers investigated the chemical composition of atmospheric PM10 at Linate Airport, focusing on eight rubber tire-related chemical markers (BTHs) and twenty-three other chemical species, aiming to find tracers specifically linked to airport activities. The team discovered that BTH concentrations in outdoor airport PM10 were much higher than in other trafficked Italian cities, pointing to the significant input of these chemicals due to airport activities.
Additional insights emerged when considering the location and surroundings of the sampling spot. The PM10 was sampled in an area influenced by two main sources of benzothiazoles: roads and parking on the right side, and airport activities on the left side. “By cross-referencing our results with wind direction data, we managed to discriminate the contribution of the two sources,” explained lead author Dr. Giovanna Mazzi. “This way, we discovered that the airport emits especially four benzothiazoles, two of which demonstrated a strong correlation among each other.” Notably, the same compounds did not show this behavior in airborne urban PM10 sampled in other cities of Northern Italy, highlighting that they might be linked to airport activities.
An ecotoxicological assessment highlighted a low potential risk of occupational exposure to BTHs in outdoor air at Linate Airport. “Although further research is still needed, these findings represent a key step toward identifying specific chemical markers for tracing airport non-exhaust emissions into the air,” Mazzi added.
The study was funded by the Next Generation EU project “GRINS - Growing Resilient, INclusive and Sustainable” (PE0000018), National Recovery and Resilience Plan (NRRP) PE9 Mission 4, C2, Intervention 1.3, and supported within the framework of the Department of Excellence 2023–2027 and the ITINERIS project.
