title: Estimations of primary nitrogen dioxide exhaust emissions from chemiluminescence NOx measurements in a UK road tunnel.
abstract: NO and NO(2) measurements have been made using the chemiluminescence method from 115 weekdays during the period 4th Jan-10th Sep 2010 in a well characterised, unventilated tunnel on the Leeds Inner Ring Road. Measurements are made at two points in the tunnel and the difference in NO and NO(2) was attributed to emissions from vehicles in the tunnel. These data have been used to determine the fraction of NOx (NO+NO(2)) as primary NO(2) (f-NO(2)) from vehicles using the tunnel. The average value of f-NO(2) from 7 am to 7 pm was 0.17 (-0.03)(+0.01) in agreement with estimations from the UK National Atmospheric Emissions Inventory (NAEI). However, during the day there was a reproducible increase in f-NO(2) from approximately 0.10 at 7 am to 0.21 at 7 pm which is not reproduced with the current UK vehicle fleet emissions inventories. The increase in f-NO(2) can be qualitatively linked to a decrease in the fraction of NOx arising from heavy goods vehicles and buses.
authors.affiliation: School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK.
authors.forename: W A
authors.initials: WA
authors.lastname: Simmons
authors.forename: P W
authors.initials: PW
authors.lastname: Seakins
mesh_terms: D004739:England; D004784:Environmental Monitoring / Q000379:methods / Q000706:statistics & numerical data*; D008163:Luminescent Measurements / Q000379:methods*; D009569:Nitric Oxide / Q000032:analysis*; D009585:Nitrogen Dioxide / Q000032:analysis*; D013997:Time Factors; D001335:Vehicle Emissions / Q000032:analysis*
chemical_list: D001335:Vehicle Emissions; D009569:Nitric Oxide; D009585:Nitrogen Dioxide