University of Vaasa - Vaasan yliopisto

559
between the so-called ozone precursors: NOx 84, CO85, CH4 and NMVOC86 .
Emissions from industrial facilities and electric utilities, motor vehicle exhaust,
gasoline vapors, and chemical solvents are some of the major sources of NOx, CO
and VOC87.
Beside its direct effect as a GHG, "bad" ozone is also known to damage vegetation
and ecosystems. It leads to reduced agricultural crop and forest yields, reduced
growth and survivability of tree seedlings, and increased susceptibility to diseases,
pests and other stresses. In particular it decreases carbon uptake by plants, indirectly
restraining them in their role in CO2 emissions reduction.
Finally, according to Sitch (2007), NOx diminish CH4 presence in the atmosphere,
somehow counterbalancing their harmful direct effect as ozone precursors.
Figure 2 - Major interactions between GHG and their main sources
As different crops have different levels of GHG emissions (Searchinger et al. 2008),
because of variable agricultural practices (fertilisers and pesticides application, soil
work, etc.), direct and indirect land-use changes have different impacts on emissions
(see figure 3).
33 Oxides of nitrogen
34 Oxide of carbon
35 Non Methane Volatile Organic Compounds
36 Volatile Organic Compounds