Monoterpene source emissions from Chamonix in the Alpine Valleys

Measurements of volatile organic compounds (VOCs) and in particular biogenic VOCs were taken near Chamonix, in the alpine valleys within the framework of the POVA program (Alpine Valley Pollution). The general topics of the program were the comparative studies of air quality in the Chamonix and Maurienne valleys (France) and the modelling of atmospheric chemistry. The main objective is to characterize the pollution sources and study the relationship between atmospheric dynamics and pollution events. To do this, it was necessary to take into account all quantifiable and localizable sources. Measurements of VOCs showed an abnormally high quantity of monoterpene concentrations (around 10% in mass of the total VOC concentrations). Isoprene and monoterpenes produced mainly by vegetation are among the most abundant natural VOCs, but these measurements were carried out in winter and during this season biogenic emissions are weak. The aim of this present work is to determine and understand this phenomenon. Domestic heating, generally not taken into account in studies of outdoor air, had a considerable impact on terpene concentrations in the valley.