Individual hydrocarbons, aldehydes/ketones, PAH, volatile organics on soot, sulfate. HCN, phenols and ammonia were selected from eight european automotive industries for round robin testing. Known and unknown standard mixtures and known and unknown exhaust samples led to an confidence range from 9 to 390 %. Special standardization lowered the range to less than 50 %.International standardization and a new roundrobin testing with increased participants including CRC- and CEC-working groups is recommended. The committee of Common Market Automobile Constructors (CCMC)/Emission Research Management Committee (ERMC) recommends to start with PAH and aldehydes/ketones.