Presently no precise statistics data is available to characterise the trend in a number of passenger cars in individual SR cities that would be based on the following criteria:

cubic capacity
catalyst presence, and on this fact based
emission situation in cities.

 The study „Total emissions from the SR traffic“ conducted for the purposes of the CORINAIR 95 international project by EDUCO-Consult Žilina for SHMÚ Bratislava provides a partial insight into the above mentioned trend and its related problems. Within the project framework the performance (in percentages) of individual vehicle categories were estimated according to specified cubic capacities of vehicles
 

Passenger cars to 1400 ccm:	Passenger cars from 1400 to 2000 ccm:
39% in cities  42-45% outside cities  16-18% on motorways	35-38% in cities  44-47% outside cities  18% on motorways
Passenger cars above 2000 ccm:	Lorries above 3.5 tonnes:
34-35% in cities  48-50% outside cities  15-18% on motorways	5-20% in cities  45-70% outside cities  17-20% on motorways

The above mentioned data show that passenger cars are the main contributors to the traffic emissions in the urban areas.
 
 

The passenger cars in 1995 by engine types and cubatures	Fuel consumption of passenger cars in 1995 by engine types and cubatures

Emissions by road transport
Emissions from traffic (1996)