Characterisation of NMHCs in a French urban atmosphere: overview of the main sources.
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.
Borbon
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A
Département Chimie et Environnement, Ecole des Mines de Douai, France. borbon@ensm-douai.fr
Locoge
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N
Veillerot
M
M
Galloo
J C
JC
Guillermo
R
R