Not much. Does it matter? Yes, it does. And what can we do about it?
Vehicle exhaust emissions matter from a human health point of view. Motor vehicles produce fine particulate matter, unburnt hydrocarbons, nitrogen oxides, and other pollutants. The fine particulate matter alone was estimated in 2002 to cause 399 premature adult deaths per year. That’s a lot. Compare it with the death toll from road vehicle crashes, 297 in 2014. Vehicle emissions matter to the global climate. The transport sector, dominated by motor vehicles, contributes 19% of New Zealand’s total GHG emissions. In addition there are sound economic and energy security reasons why fuel economy matters even like now when oil prices are low.
There are four different types of regulatory lever used in different countries to improve vehicle emissions.
- Fuel efficiency standards, or fuel economy standards, for motor vehicles. They work on fuel consumption per kilometre – on miles per gallon or litres per hundred km. The American Corporate Average Fleet Economy or “CAFE” standards have gradually required better performance in passenger cars and light trucks. The standard is an average for each manufacturer or importer, so that the company has flexibility in offering a range of different vehicles. New Zealand has no such standards.
- Vehicle emission standards. For many years these have been addressed to local or regional air pollution. New Zealand has such standards, as we will see in a minute. In some countries vehicle emission standards control GHG emission, in grams of CO2 equivalent per kilometre travelled.
- Renewable fuel content standards, which require a minimum percentage of biofuel in the fuel sold to road users. Low-carbon fuel requirements are a more recent variation. New Zealand had a biofuel standard until 2008.
- Labelling requirements, which make sure that purchasers of vehicles have informatio