Seasonal variation of water-soluble inorganic components in aerosol size-segregated at the puy de Dôme station (1,465 m a.s.l.), France

Abstract

The size-segregated chemical composition of aerosol particles was investigated during 1 year at the puy de Dome (1,465 m a.s.l.), France. These measurements aimed to a better understanding of the influence of the air mass origin on the size-segregated chemical composition of the aerosol at an altitude site. Mountain site measurements are important because they are representative of long range transport and useful for model validation. PM1 mass concentration exhibits a seasonal variability with a summer maximum. The composition of PM1 did not change significantly in terms of relative contribution of water soluble inorganic ions but is rather variable in term of total mass concentrations. For the PM10-1, a different seasonal behaviour was found with maxima concentrations in autumn-winter. Aerosols were classified into four different categories according to their air mass origin: marine, marine modified, continental and Mediterranean. The PM10 aerosol mass at 50 % relative humidity was close to 2.5 μg m−3 in the marine, 4.3 μg m−3 in the marine modified, 10.3 μg m−3 in the continental and 7.7 μg m−3 in the Mediterranean sectors. We noted that the influence of the air mass origin (on the chemical properties) could be seen especially on the PM10-1. A significant PM10-1 mode was found in marine, modified marine, and Mediterranean air masses, and PM1 dominated in the continental air masses samples. As a result, the aerosol chemical composition variability at the puy de Dome is a function of both the season and air mass type and we provide a chemical composition of the aerosol as a function of each of these environmental factors.