Association between short-term exposure to ultrafine particles from aviation and mortality in the proximity of Amsterdam Airport Schiphol in the Netherlands

Most research on the association between ultrafine particle (UFP) exposure and mortality has taken into consideration total UFP particle number concentrations, while less is known about associations between source-specific UFP and mortality. Recent studies have reported high concentrations of UFP in the proximity of airports. The aim of this study was to assess the association between short-term exposure to UFP from aviation (UFP-aviation) from Amsterdam Airport Schiphol (the Netherlands) and natural, circulatory, and respiratory mortality. The study population included all non-accidental mortality cases in a 50 × 56 km area around the airport. Hourly UFP-aviation concentrations were estimated using the STACKS + dispersion model at 5174 grid points in a 50 × 56 km area around the airport and averaged to obtain daily values from 2003 until 2019. Cause-specific daily death records were retrieved from Statistics Netherlands (CBS). We used a time-stratified case-crossover design, with control days matched by the year, month, and weekday as the corresponding day of death. To assess associations, we ran conditional logistic regressions adjusting for public holidays, temperature, and relative humidity. The results were reported as odds ratios (OR) and 95 % confidence intervals (CI) per 1 IQR increase of 1972 pt/cm³. Throughout the study period we observed 260,649 natural, 75,015 circulatory and 25,122 respiratory deaths. There was no association between UFP-aviation (lag0-4) and natural (OR: 0.996 [0.991-1.001]), circulatory (OR: 0.995 [0.986-1.005]) and respiratory mortality, (OR: 0.985 [0.969-1.002]). To check the robustness of our results, we repeated the analyses using different lag exposures (lag0, lag0-1, lag0-7), we adjusted for other key pollutants (NO₂, PM₁₀ and O₃), and selected smaller study areas. These analyses resulted in null associations between UFP-aviation and mortality. Effect modification by sex, age, season, place of death and time period yielded no differences between strata. In conclusion, our study found no association between short-term exposure to UFP-aviation and natural, circulatory, or respiratory mortality in the area around Amsterdam Airport Schiphol.