Effectiveness of flow through catalytic diesel particulate aftertreatment devices in reducing particulate emissions is investigated on Ford's 1360 kg (3000 lb.) Sierra 1.8L Turbo-Diesel passenger car. Flow-through monolith type EAO reference catalyst and AC Rochester diesel catalyst are evaluated using Phillip's Control No. 2 diesel fuel, low sulfur (0.05% S) and ultra-low sulfur (0.001% S) diesel fuels. Comparisons are made with baseline exhaust emissions for FTP75 and Highway chassis dynamometer test procedures. Effects of catalyst aging of 320, 1610 and 6450 km (200, 1000 and 4000 miles) are examined. Results, based on 6450 km (4000 mile) limited durability, show that a ceramic monolith substrate of 400 cells per square inch (cpsi) with AC Rochester catalyst is capable of reducing particulate as well as HC and CO emissions to well below the 1994 Government mandated emission requirements with low (0.05% S) and ultra low (0.001% S) sulfur fuel. This diesel catalyst is recommended as a serious candidate for 162,000 km (100,000 miles) qualification testing. Use of EGR is also a potential means of achieving reduced NOx emissions. However, meeting the NOx standards poses a formidable challenge.