Aerosol decadal trends – Part 2. In-situ aerosol particle number concentrations at GAW and ACTRIS stations ...

• Main Authors: Asmi, Ari, Collaud Coen, Martine, Ogren, John A., Andrews, Elisabeth, Sheridan, Patrick, Jefferson, Anne, Weingartner, Ernest, Baltensperger, Urs, Bukowiecki, Nicolas, Lihavainen, Heikki, Kivekäs, Niku, Asmi, Eija, Aalto, Pasi Pekka, Kulmala, Markku, Wiedensohler, Alfred, Birmili, Wolfram, Hamed, Amar, O'Dowd, Colin, Jennings, Stephen G., Weller, Rolf, Flentje, Harald, Fjaeraa, Ann Mari, Fiebig, Markus, Myhre, Cathrine Lund, Hallar, Anna Gannet, Swietlicki, Erik, Kristensson, Adam, Laj, Paolo
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus 2013
• Subjects: 550 - Geowissenschaften; Antarc*; Antarctica
• Online Access: https://dx.doi.org/10.26041/fhnw-8164; https://irf.fhnw.ch/handle/11654/44361

We have analysed the trends of total aerosol particle number concentrations (N) measured at long-term measurement stations involved either in the Global Atmosphere Watch (GAW) and/or EU infrastructure project ACTRIS. The sites are located in Europe, North America, Antarctica, and on Pacific Ocean islands. The majority of the sites showed clear decreasing trends both in the full-length time series, and in the intra-site comparison period of 2001–2010, especially during the winter months. Several potential driving processes for the observed trends were studied, and even though there are some similarities between N trends and air temperature changes, the most likely cause of many northern hemisphere trends was found to be decreases in the anthropogenic emissions of primary particles, SO2 or some co-emitted species. We could not find a consistent agreement between the trends of N and particle optical properties in the few stations with long time series of all of these properties. The trends of N and the proxies ...