TY - JOUR

T1 - Seasonal changes in the daily emission rates of terpenes by Quercus ilex and the atmospheric concentrations of terpenes in the natural park of Montseny, NE Spain

AU - Llusia, Joan

AU - Peñuelas, Josep

AU - Seco, Roger

AU - Filella, Iolanda

PY - 2012

Y1 - 2012

N2 - We studied the daily patterns in the rates of terpene emissions by the montane holm oak, Quercus ilex, in three typical days of winter and three typical days of summer in Montseny, a natural park near Barcelona, and related them to the air concentrations of terpenes, ozone and NO 2. Terpene emission rates were about 10 times higher in summer than in winter. Emissions virtually stopped in the dark. In both seasons, rates of terpene emissions were well correlated with light, air temperature and relative humidity. Rates of emissions were also correlated with stomatal conductance and the rates of transpiration and photosynthesis. Almost all the individual terpenes identified followed the same pattern as total terpenes. The most abundant terpene was α-pinene, followed by sabinene + β-pinene, limonene, myrcene, camphene and α-phellandrene. Atmospheric terpene concentrations were also about 10 times higher in summer than in winter. A significant diurnal pattern with maxima at midday was observed, especially in summer. The increase by one order of magnitude in the concentrations of these volatile isoprenoids highlights the importance of local biogenic summer emissions in these Mediterranean forested areas which also receive polluted air masses from nearby or distant anthropic sources. Atmospheric concentrations of O 3 and NO 2 were also significantly higher in summer and at midday hours. In both seasons, concentrations of O 3 were significantly correlated with concentrations of terpenes and NO 2 in the air and with rates of terpene emission.

AB - We studied the daily patterns in the rates of terpene emissions by the montane holm oak, Quercus ilex, in three typical days of winter and three typical days of summer in Montseny, a natural park near Barcelona, and related them to the air concentrations of terpenes, ozone and NO 2. Terpene emission rates were about 10 times higher in summer than in winter. Emissions virtually stopped in the dark. In both seasons, rates of terpene emissions were well correlated with light, air temperature and relative humidity. Rates of emissions were also correlated with stomatal conductance and the rates of transpiration and photosynthesis. Almost all the individual terpenes identified followed the same pattern as total terpenes. The most abundant terpene was α-pinene, followed by sabinene + β-pinene, limonene, myrcene, camphene and α-phellandrene. Atmospheric terpene concentrations were also about 10 times higher in summer than in winter. A significant diurnal pattern with maxima at midday was observed, especially in summer. The increase by one order of magnitude in the concentrations of these volatile isoprenoids highlights the importance of local biogenic summer emissions in these Mediterranean forested areas which also receive polluted air masses from nearby or distant anthropic sources. Atmospheric concentrations of O 3 and NO 2 were also significantly higher in summer and at midday hours. In both seasons, concentrations of O 3 were significantly correlated with concentrations of terpenes and NO 2 in the air and with rates of terpene emission.

KW - Montseny

KW - Quercus ilex

KW - Seasonality

KW - Terpene air concentrations

KW - Terpene emission rates

KW - VOC

U2 - 10.1007/s10874-012-9238-1

DO - 10.1007/s10874-012-9238-1

M3 - Journal article

AN - SCOPUS:84867867345

VL - 69

SP - 215

EP - 230

JO - Journal of Atmospheric Chemistry

JF - Journal of Atmospheric Chemistry

SN - 0167-7764

IS - 3

ER -