The California Air Resources Board (CARB) plans to adopt in December new, optional ultra-low nitrogen oxides (NOx) emission standards for diesel truck engines. CARB says it wants to use incentives to encourage engine makers to introduce new technologies to reduce NOx below the current mandatory diesel engine emission standards for model years 2010 and later, set at 0.2 grams NOx per brake horsepower-hour. The proposed new standards will be between 50 and 90 per cent stricter than the current one. The board is also considering a future mandatory low-NOx engine standard, but is waiting on pending research to support such a rulemaking.
Source: Car Lines No 5, October 2013