1. Cooperative Institute for Research in Environmental Sciences; University of Colorado; Boulder Colorado USA
2. Top Analytica Ltd.; Turku Finland
3. Department of Chemistry and Biochemistry; University of Colorado; Boulder Colorado USA
4. Aeronomy Laboratory; National Oceanic and Atmospheric Administration; Boulder Colorado USA
5. Department of Biological and Environmental Sciences; University of Helsinki; Helsinki Finland
6. Nordic Envicon Oy; Helsinki Finland
7. Department of Physical Sciences; University of Helsinki; Helsinki Finland