Volatile organic compounds emissions data

Data from the EEA (2006c) reveal that air emissions from transport follow a slightly less expressed, but well comparable trend to entire emissions between 1990 and 2004. Table 19.2 shows the share for the transport sector of certain pollutants in the EU 40% to 50% of NO, and carbon monoxide (CO), 25% of non-methane volatile organic compounds (NMVOC) and just 1% of sulphur oxides (SO,). In developing countries, and here in particular in the big megacities, the share for transport of SO, heavy metal and particulate emissions (not listed here) will -because of the old vehicle fleets - be much higher. 

In the following discussion, three types of air pollutant analytical data will be examined using principal component analysis and the K-Nearest Neighbor (KNN) procedure. A set of Interlaboratory comparison data from X-ray emission trace element analysis, data from a comparison of two methods for determining lead In gasoline, and results from gas chromatography/mass spectrometry analysis for volatile organic compounds In ambient air will be used as Illustrations. 

Volatile emissions from vegetation include hydrocarbons other than isoprene and terpenes. Altshuller (1983) has compiled emission data available to him [mainly from Zimmerman (1979a,b)]. The emissions contained C2-C6 alkanes, various alkenes, and C6-C12 volatile organic compounds. Practically every deciduous plant and all the grasses studied emitted alkanes with ethane and propane dominating the mixture. Twenty to 50% of total hydrocarbon emissions, on average, consisted of alkanes. 

Volatile complexes of organic compounds of metals are, however, used more widely in GC analysis [45, 46, 211]. The main adwmti e of the GC analysis of volatile compounds of metals is the possibility of analysing trace amounts of metals with the use of ECDs and microwave emission detectors. When detectors of this type were used, GC methods were compared with such methods as neutron-activation analysis and atomic-absorption spectroscopy. The field of apphcation for this method is indicated in Table 1.5, illustrating the analysis of trace amounts of elements in the form of volatile complexes and compiled from data pubUshed in the literature. 

The observed ambient organic aerosol formation rates are also consistent with those estimated by extrapolation of smog-chamber kinetic data. Other heavy unsaturates, such as styrene and indene, are present in the atmosphere and may contribute, in part, to the formation of benzoic acid and homophthalic acid, respectively. Diesel exhaust and industrial emission are possible sources of such heavy unsaturates. Diolefins of C6+ are not present in gasolines and exhaust gases and have not been found in the atmosphere, and their possible role as precursors of the Cs-7 difiinctional acidic compounds is seriously challenged. Lower diolefins are emitted in automobile exhaust. Examination of vapor-pressure data indicates that the bulk of their expected photooxidation products remains in the gas phase, including most of the less volatile C3-4 dicarboxylic acids. 

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