3 years ago

OH reactivity of the urban air in Helsinki, Finland, during winter

A new instrument to measure total OH reactivity in ambient air based on the Comparative Reactivity Method (CRM) has been built and characterized at the Finnish Meteorological Institute in Helsinki, Finland. The system is based on the detection of pyrrole by a gas chromatograph with a photoionization detector and designed for long term studies. It was tested in a container close to the SMEAR III semi-urban station in Helsinki during the winter in February 2016. The sampling location next to the delivery area of the institute was influenced by local vehicle emissions and cannot be considered representative of background conditions in Helsinki. However, effects of nitrogen oxides on the measurements could be investigated there. During this campaign, 56 compounds were measured individually by 1) an in-situ gas chromatograph coupled to a mass spectrometer (GC/MS) and by 2) off-line sampling in canisters and on adsorbent filled cartridges taken at the container and subsequently analysed by GC-FID and liquid chromatography, respectively. In addition, nitrogen oxides were measured at the same location, while ozone, carbon monoxide and sulfur dioxide concentrations have been retrieved from the SMEAR III mast data. The comparison between the total OH reactivity measured and the OH reactivity derived from individual compound measurements are in better agreement for lower reactivity levels. Possible explanations for the differences are discussed in detail.

Publisher URL: www.sciencedirect.com/science

DOI: S1352231017305939

You might also like
Never Miss Important Research

Researcher is an app designed by academics, for academics. Create a personalised feed in two minutes.
Choose from over 15,000 academics journals covering ten research areas then let Researcher deliver you papers tailored to your interests each day.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.