Environmental protection is becoming an increasingly important issue in every area of life. In recent times, a great emphasis has been placed on reducing the negative impact of automotive on human health at every stage of the vehicle's life. The most common impact of cars on the environment is the emission of pollutants from the exhaust system, created during the combustion of fuels in internal combustion engines. For this purpose, legislators introduce emission standards that must be met at the stage of vehicle approval for a given market. To meet these requirements, vehicle manufacturers modify the design of the drive units, body, and chassis to reduce weight and improve aerodynamic properties. This approach is methodologically correct because it is possible to compare the results obtained for different vehicles, but in real operation the level of harmful exhaust compounds, emissions and fuel consumption depend very much on the way the vehicle is used. As a manner of operation one can understand a variable load in the form of passengers or cargo, driving style, share of urban, extra-urban and motorway driving, terrain formation, ambient temperature and others. This article addresses issues related to the assessment of the impact of the light commercial vehicle operation manner on fuel consumption and the emission of harmful exhaust compounds. The problem was analysed in terms of the difference in vehicle load and driving style. Exhaust emission measurements were carried out using PEMS (Portable Emission Measurement System) analysers, which are state of the art devices for measuring exhaust emission in real operating conditions, called RDE (Real Driving Emissions).