title: Characterisation of NMHCs in a French urban atmosphere: overview of the main sources.
abstract: Continuous hourly air quality data involving 37 C2-C9 non-methane hydrocarbons (NMHC) over 4 years are reported for the first time in Lille metropol, northern France, at two urban roadside and background sites. The data have been analysed in two complementary steps: univariate statistics which define the spatial and temporal characteristics of NMHC by constructing the seasonal and daily concentration profiles, and multivariate statistics based on principal component analysis (PCA). A number of important sources have been clearly identified depending on the season: (1) motor vehicle exhaust, which dominates the NMHC distribution and particularly in winter, even for isoprene; (2) wintertime stationary combustion and activities related to fossil fuel consumption in general, such as natural gas leakage of ethane and propane; (3) summertime evaporative emissions from fuel and solvent; and (4) summertime biogenic emissions through isoprene behaviour and their dependence on temperature.
authors.affiliation: Département Chimie et Environnement, Ecole des Mines de Douai, France. borbon@ensm-douai.fr
authors.forename: A
authors.initials: A
authors.lastname: Borbon
authors.forename: N
authors.initials: N
authors.lastname: Locoge
authors.forename: M
authors.initials: M
authors.lastname: Veillerot
authors.forename: J C
authors.initials: JC
authors.lastname: Galloo
authors.forename: R
authors.initials: R
authors.lastname: Guillermo