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End date: 2024 × Start date: 2020 × Type: article × Version: publishedVersion × Subject: Germany × Subject: air quality ×

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    Nucleation of jet engine oil vapours is a large source of aviation-related ultrafine particles
    (London : Springer Nature, 2022) Ungeheuer, Florian; Caudillo, Lucía; Ditas, Florian; Simon, Mario; van Pinxteren, Dominik; Kılıç, Doğuşhan; Rose, Diana; Jacobi, Stefan; Kürten, Andreas; Curtius, Joachim; Vogel, Alexander L.
    Large airports are a major source of ultrafine particles, which spread across densely populated residential areas, affecting air quality and human health. Jet engine lubrication oils are detectable in aviation-related ultrafine particles, however, their role in particle formation and growth remains unclear. Here we show the volatility and new-particle-formation ability of a common synthetic jet oil, and the quantified oil fraction in ambient ultrafine particles downwind of Frankfurt International Airport, Germany. We find that the oil mass fraction is largest in the smallest particles (10-18 nm) with 21% on average. Combining ambient particle-phase concentration and volatility of the jet oil compounds, we determine a lower-limit saturation ratio larger than 1 × 105 for ultra-low volatility organic compounds. This indicates that the oil is an efficient nucleation agent. Our results demonstrate that jet oil nucleation is an important mechanism that can explain the abundant observations of high number concentrations of non-refractory ultrafine particles near airports.
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    Ambient carbon monoxide and daily mortality: a global time-series study in 337 cities
    (Amsterdam : Elsevier, 2021) Chen, Kai; Breitner, Susanne; Wolf, Kathrin; Stafoggia, Massimo; Sera, Francesco; Vicedo-Cabrera, Ana M.; Guo, Yuming; Tong, Shilu; Lavigne, Eric; Matus, Patricia; Valdés, Nicolás; Kan, Haidong; Jaakkola, Jouni J. K.; Ryti, Niilo R. I.; Huber, Veronika; Scortichini, Matteo; Hashizume, Masahiro; Honda, Yasushi; Nunes, Baltazar; Madureira, Joana; Holobâcă, Iulian Horia; Fratianni, Simona; Kim, Ho; Lee, Whanhee; Tobias, Aurelio; Íñiguez, Carmen; Forsberg, Bertil; Åström, Christofer; Ragettli, Martina S.; Guo, Yue-Liang Leon; Chen, Bing-Yu; Li, Shanshan; Milojevic, Ai; Zanobetti, Antonella; Schwartz, Joel; Bell, Michelle L.; Gasparrini, Antonio; Schneider, Alexandra
    Background Epidemiological evidence on short-term association between ambient carbon monoxide (CO) and mortality is inconclusive and limited to single cities, regions, or countries. Generalisation of results from previous studies is hindered by potential publication bias and different modelling approaches. We therefore assessed the association between short-term exposure to ambient CO and daily mortality in a multicity, multicountry setting. Methods We collected daily data on air pollution, meteorology, and total mortality from 337 cities in 18 countries or regions, covering various periods from 1979 to 2016. All included cities had at least 2 years of both CO and mortality data. We estimated city-specific associations using confounder-adjusted generalised additive models with a quasi-Poisson distribution, and then pooled the estimates, accounting for their statistical uncertainty, using a random-effects multilevel meta-analytical model. We also assessed the overall shape of the exposure–response curve and evaluated the possibility of a threshold below which health is not affected. Findings Overall, a 1 mg/m3 increase in the average CO concentration of the previous day was associated with a 0·91% (95% CI 0·32–1·50) increase in daily total mortality. The pooled exposure–response curve showed a continuously elevated mortality risk with increasing CO concentrations, suggesting no threshold. The exposure–response curve was steeper at daily CO levels lower than 1 mg/m3, indicating greater risk of mortality per increment in CO exposure, and persisted at daily concentrations as low as 0·6 mg/m3 or less. The association remained similar after adjustment for ozone but was attenuated after adjustment for particulate matter or sulphur dioxide, or even reduced to null after adjustment for nitrogen dioxide. Interpretation This international study is by far the largest epidemiological investigation on short-term CO-related mortality. We found significant associations between ambient CO and daily mortality, even at levels well below current air quality guidelines. Further studies are warranted to disentangle its independent effect from other traffic-related pollutants.