Sign up & Download
Sign in

Atmospheric hydrogen variations and traffic emissions at an urban site in Finland

by T. Aalto, M. Lallo, J. Hatakka, T. Laurila
Atmospheric Chemistry and Physics Discussions ()


Atmospheric hydrogen (H2) mixing ratios were observed over a one year period from summer 2007 to 2008 in Helsinki, Finland. Relatively stable background values of hydrogen were occasionally observed at the site, with minimum in October and maximum between March and May. High hydrogen mixing ratios occurred simultaneously with high carbon monoxide (CO) values and coincided with high traffic flow periods. Carbon monoxide and radon (222Rn) were continuously monitored at the same site and they were used in estimation of the hydrogen emissions from traffic. The morning rush hour slope of ΔH2/ΔCO was in average 0.43±0.03 ppb (H2)/ppb (CO). After correction due to soil deposition of H2 the slope was 0.49±0.07 ppb (H2)/ppb (CO). Using this slope and CO emission statistics, a road traffic emission of about 260 t (H2)/year was estimated for Helsinki in 2007.

Cite this document (BETA)

Readership Statistics

9 Readers on Mendeley
by Discipline
by Academic Status
22% Post Doc
22% Researcher (at an Academic Institution)
22% Researcher (at a non-Academic Institution)
by Country
11% Netherlands


Sign up today - FREE

Mendeley saves you time finding and organizing research. Learn more

  • All your research in one place
  • Add and import papers easily
  • Access it anywhere, anytime

Start using Mendeley in seconds!

Sign up & Download

Already have an account? Sign in