The 1.6l petrol car produced twice the volume of ozone emissions of the 1.9l diesel, both being equipped with catalytic conversion devices, on a rolling road programme simulating urban driving conditions. Tests were carried out at different effective speeds. In stop-start conditions, the diesel's pollutant emissions ranged between 0-5% while those of the petrol car ranged from 10-15%.
On the other hand, the diesel car in the test was let down by its particulate emissions, notwithstanding the fitment of the PSA Peugeot Citroen filter, which traps 90% of particulate emissions. Such filters are likely to become the norm on new diesel cars from next year, when Euro 4 emissions limits halve the current permitted emissions of particulates. (Source: CCFA, the French vehicle manufacturers' association)