Vehicle PM, NOx, CO, and HC emissions: Progress and Challenges

T. J. Wallington a)

a) Research & Advanced Engineering, Ford Motor Company, Dearborn, MI, 48121-2053, USA

Over the past few decades vehicle tailpipe emissions of particulate matter (PM), nitrogen oxides (NOx), carbon monoxide (CO), and hydrocarbons (HCs) have decreased significantly.  Advanced emission after-treatment technologies have been developed for gasoline and diesel vehicles to meet increasingly stringent regulations, yielding absolute emission reductions from the fleet despite increased vehicle travel.  As a result of mobile and stationary source emission controls, air quality has generally improved substantially in cities across the U.S. and Europe.  Emission regulations (such as Tier 3 in the U.S., LEV III in California, and Euro 6 rules in the EU) will lead to decreased emissions and improvements in air quality.  Historical vehicle emission and air quality trends and the future outlook for air quality will be discussed.