s i d e b a r
EPA Emission Standards for
Heavy Duty Diesel Engines
Year HC CO NOx PM Heavy-Duty Diesel Truck Engines 1990 1.3 15.5 6.0 0.60 1991 1.3 15.5 5.0 0.25 1994 1.3 15.5 5.0 0.10 1998 1.3 15.5 4.0 0.10 Urban Bus Engines 1991 1.3 15.5 5.0 0.25 1993 1.3 15.5 5.0 0.10 1994 1.3 15.5 5.0 0.07 1996 1.3 15.5 5.0 0.05 1998 1.3 15.5 4.0 0.05