INTRODUCTION Since motor vehicle exhaust was identified as an atmospheric contaminant of some importance@ a substantial amount of work has been completed to identify the constituents present in vehicle exhaust and blow by gases@ to understand the reaction mechanisms involved in the formation of photochemical smog@ and to develop control methods to alleviate this type of air pollution. Much of this work has been limited to studies of gasoline vopor and oxides of nitrogen@ since these constituents ore important in the formation of photochemical smog. Investigations have also been made of the problems of smoke aid odor from diesel exhaust. Since these effects of diesel powered vehicles are most noticeable to the general public@ these studies have concentrated mainly on soot production and on aldehydes and other odor causing constituents. Compounds higher in molecular weight than the gasoline range have been largely neglected@ in port because they constitute a relatively minor fraction of the total exhaust and blow by@ and in port because no undesirable smog manifestations hove been identified as o result of the presence of such compound. In view of the importance of motor vehicles in community air pollution problems@ however@ it is important to examine all possible constituents. Therefore@ the Sampling and Analysis Panel of the CRC-Motor Group on Composition of Exhaust Gases established a Study Sub-Panel on High Molecular Weight Compounds to examine the present state of knowledge in this field as on aid to determining whether or not further consideration by the Coordinating Research Council is warranted. A literature survey was undertaken in accordance with action approved by the Sampling and Analysis Panel in June 1964 for the preparation of a report by the Study Sub-Panel which would present a summary of the state-of-the-ort regarding methods of measuring and analyzing high molecular weight compounds found in automobile exhaust.