Rural O_3 Levels in the Middle Ebro Basin During the Plant Growing Season

摘要

Ground-level dynamics of O_3, NO_x and benzene, toluene, ethylbenzene and xylenes were characterised at rural sites in the medium Ebro River Basin (Northern Spain) from April to September (2003-2007) and by means of automated and passive monitoring. The study registered high O_3 levels within the area, which were influenced by traffic emissions, and a monthly evolution of these levels consistent with the occurrence of a broad summer maximum, typical of polluted areas. The mean ozone concentration registered in the studied area by means of passive sampling was 87±12 μg m~(-3). The 2008/50/EC objective value for the protection of vegetation was widely exceeded during this study (AOT40=57,147± 14,114 μg m~(-3) h), suggesting that current ambient levels may pose a risk for crops and vegetation in this important agroindustrial region.