3.3.2. By region
Fig. 7 presents the distribution of 2006 emissions together with
the number of vehicles. The City of Buenos Aires exhibited the highest emissions for all compounds, followed by the western, southern and northern regions. The three neighboring regions presented higher shares of the byproducts of incomplete combustion (CO, NMVOC) than the City, compared with CO
shares, because of different technology distribution between regions, where the City concentrated a major proportion of newer, more efficient vehicles. NO
emissions presented a similar situation based on the higher ratio of older gasoline vehicles of the surrounding regions. Regarding PM emissions, the City, and the southern and western regions, presented a greater PM/CO
x
ratio than the northern region, driven by the main emitting categories conventional diesel light and heavy-duty vehicles.