21.   World shortages are threatening to disrupt production of catalytic converters, used to clean automobile exhaust emissions.

22.   World shortages have also threatened to disrupt production of catalytic converters, used in cars to clean exhaust emissions.

23.   World shortages of the metals are threatening to disrupt production of catalytic converters, used to clean automobile exhaust emissions.

24.   World shortages are threatening to disrupt production of catalytic converters, used to control automobile exhaust emissions.

25.   Engine management equips and calibrates engines to provide a minimum of exhaust emissions while achieving higher levels of performance and fuel economy.

26.   Khampin claimed that the panel once submitted a proposal on how to test vehicle exhaust emissions to the PCD, but the agency rejected it.

27.   Many experts believe that about half of those come from traffic pollution, which includes not only exhaust emissions but also dust from tires and debris disturbed by traffic.

28.   Nissan Motor Co. said Friday it has developed a fuel-efficient engine system combining an electric motor with a gasoline engine to cut exhaust emissions dramatically.

29.   The government has imposed tighter standards for exhaust emissions from new cars and encouraged the use of cleaner fuels including lead-free gas and ultra-low sulfur diesel.

30.   Hyundai officials are also concerned about a South Korean government plan to tighten rules on diesel engine exhaust gas emissions from July.