Although the trucking industry has become progressively cleaner, the dirtiest diesels on the road are much heavier polluters than the average big rig.
That’s the conclusion of new research that Metro Vancouver says underscores the need for new ways to curb the worst offenders.
Metro used roadside sensors on a parked trailer to test the exhaust from nearly 12,000 trucks, buses and other heavy-duty equipment last summer.
Emission standards have been tightened steadily over the years and older trucks account for a disproportionate share of the industry’s emissions.
But the testing found “gross emitters” – the worst 10 per cent of trucks in each age group – release four to five times more nitrogen oxides and diesel soot than a typical truck of the same age and 11 times more carbon monoxide.
“Identifying these high emitters may be worth considering,” said Metro air quality planner Eve Hou.
She said emission control systems on those bad belchers may have been tampered with or failed.
Regional politicians have pushed for years to create an AirCare-like program to target heavy trucks and the province last year agreed to consider the idea, after announcing it will wind down AirCare for regular cars.
Metro is sending the test results to Victoria and plans to work with the province over the next two years to flesh out potential options for an diesel testing program.
Emissions of soot, or fine diesel particulate, are estimated to be responsible for two-thirds of the lifetime cancer risk from air pollution in Metro Vancouver.
Metro says the testing system tried last year appears to be a viable measurement method with minimal inconvenience to truckers.
It’s also able to detect high emission levels that don’t necessarily produce a visible smoke plume.
Other options that could be considered are programs to scrap old trucks or mandatory retrofit requirements, possibly coupled with incentives and fees.
Less enthusiastic about new rules and costs is the B.C. Trucking Association, which says a new AirCare program for trucks would be unnecessary and wasteful.
“A large-scale AirCare-like emissions testing program for trucks would impose unreasonable costs on the industry and produce very limited results,” president Louise Yako said.
She said an Ontario testing program found fewer than four per cent of trucks there fail.
The BCTA estimates 35 per cent of heavy-duty trucks in B.C. are now 2007 or newer models – with extremely low emissions – and they will make up 52 per cent of the provincial fleet by 2015 and 63 per cent by 2017.
“As older trucks are retired and replaced with newer, cleaner trucks, diesel emissions will naturally decline over time, making an onerous and expensive testing program unnecessary,” Yako said.