Portable Emissions Measurement Systems (PEMS)

Real-world emissions and activity monitoring of engines and vehicles in support to the European Emissions control legislation


Portable Emissions Measurement Systems, or PEMS, measure emissions from combustion engines as the vehicle or the equipment is being used, which allows real-world in-use testing.

PEMS offer a modern and innovative counterpart to check the impact of emissions from combustion engines upon the environment. The PEMS used for emissions regulatory purposes integrate advanced gas analyzers, exhaust mass flow meters, weather station, Global Positioning System (GPS) and connection to the vehicle networks. PEMS provide a complete and very accurate real-time monitoring of the pollutants emitted by the engines (HC, CO, CO2, NOx [or NO + NO2], PM) together with the associated engine, vehicle and ambient parameters.

PEMS in the European Emissions Legislation

In use emissions testing with Portable Emissions Measurement Systems (PEMS) has become one of the key elements of the European emissions legislation. The first ‘official’ step was the publication of the procedures to verify the conformity of gaseous emissions from heavy-duty engines, under the Commission Regulations (EU) 582/2011 and (EU) 64/2012.

To adapt these procedures to Non-Road Mobile Machinery (NRMM), a pilot program was launched and will address the specificities for testing and data evaluation. It will also stimulate the dissemination of know-how and the development of good practices.

More recently, in-use emissions testing with PEMS became one of the solutions envisaged to control and limit the “real-driving emissions” of passenger cars, as foreseen in the EURO 6 Regulation 715/2007, which “requests the Commission to investigate the use of "portable emission measurement systems" (PEMS) and "not-to-exceed" regulatory concepts (...) and the need to bring real world emissions in line with those measured at type approval.”