Sources and variability of non-methane hydrocarbons in the Eastern Mediterranean

The volume mixing ratios of non-methane hydrocarbons including saturated, unsaturated and
aromatic ones (C2 to C8 as non methane hydrocarbons, NMHCS) were measured at three
distinct sites (natural, rural, urban) in the lower troposphere of the Eastern Mediterranean
from February 2006 to March 2007. Average concentrations for most of the NMHC show clear
seasonal variations along the year mainly attributed to photochemistry. Significant
correlations found among various hydrocarbons indicate contribution from mobile and
stationary sources (exhaust and combustion). Leakages from natural gas (NG) or liquefied
petroleum gas (LPG) probably from the continental platforms may account for important
sources for the background concentration of ethane and propane in the area. Isoprene has
been found to have mostly a biogenic source but its dual anthropogenic–biogenic origin was
also evident at the rural site.