Barely two months after it announced a new emission scheme that takes into account five pollutants a car produces, the Government said some models will be exempted from one of the pollutant readings.
In response to queries from The Sunday Times, the National Environment Agency said yesterday petrol models with port fuel injection - where fuel is injected just before the engine's combustion chamber - will not be measured for particulate matter (fine soot).
The exemption will apply when the Euro 6 emission standard kicks in in September and when the Vehicular Emissions Scheme starts in January.
"All petrol port fuel injection (PFI) vehicles are exempted from particulate matter and particle number limits under Euro 6 emission standards," a spokesman said, adding that the agency will also accept Japan's JPN2009 standard - the country's closest equivalent to Euro 6.
"As PFI vehicles are not tested for particulate matter, they are not banded based on particulate matter emissions under the Vehicular Emissions Scheme."
Instead, they will be banded according to the other four tailpipe components - carbon dioxide, hydrocarbons, carbon monoxide and nitrogen oxides, the NEA said.
It added that the European Commission had stated that the level of particle emission from port fuel injection engines "is low".
EXEMPTED UNDER SCHEME
All petrol port fuel injection (PFI) vehicles are exempted from particulate matter and particle number limits under Euro 6 emission standards... As PFI vehicles are not tested for particulate matter, they are not banded based on particulate matter emissions under the Vehicular Emissions Scheme.
AN NEA SPOKESMAN, on the exemption.
"The EC may review this and propose further regulatory measures," an NEA spokesman said, adding that NEA would "continue to monitor international developments".
Meanwhile, the exemption is likely to benefit the majority of Japanese and some Korean cars, and could give them an edge over equivalent European models in terms of how they are taxed. Toyota's and Mitsubishi's line-ups for instance, are all port fuel injected, as well as half of Honda's line-up, and some Hyundai models.
The German brands typically lean towards direct injection, where fuel is injected directly into the combustion chamber. Compared to port fuel injection, this method is more fuel-efficient, but tends to produce more particulate matter.
Singapore Vehicle Traders Association first vice-president Raymond Tang said the exemption is good news for parallel importers, who tend to bring in more Japanese cars.
But checks revealed that some Japanese domestic models - which parallel importers bring in - are direct injected models. Hence these will be measured for particulate matter, and may not comply with Euro 6 standards because of that.
In fact, The Sunday Times understands several Japanese models which were recently tested for Euro 6 compliance here had failed.
Mr Neo Nam Heng, chairman of diversified motor group Prime, said the port fuel injection exemption is "good news because it means more models will now qualify for tax rebates".
But he added that "it does not mean all direct injection models will automatically fail".
Before the exemption, none of the 11 random models sampled by The Straits Times in March qualified for a tax break under Vehicular Emissions Scheme.
Meanwhile, an executive from a major German manufacturer said "there's no logic" for the exemption.
"Generally, port injection is not the most efficient way," he said. "So excusing it is basically undermining the supposed intent of cleaning up the air."