What Is PEMS Testing, And Why Is It Needed?

Portable Emissions Measurement System (PEMS) testing is a process of measuring a vehicle’s real-world emissions on the road using a highly accurate measurement device. When it comes to collecting emissions data, the California Air Recourses Board (CARB) encourages on-road testing to understand how the vehicle performs in the real world. Driving on the road is considered “real-world driving” due to outdoor factors such as weather, road conditions, traffic, etc., which are difficult to simulate on a chassis dyno. The PEMS effectively helps us analyze vehicle emissions while incorporating these outdoor factors. Emissions commonly measured with the PEMS device includes Carbon monoxide (CO), Non-methane hydrocarbon (NMHC), and Oxides of Nitrogen (NOx).

As regulations become more stringent, manufacturers must improve their testing methods to ensure they are meeting the standards set by regulators. CARB is already performing PEMS testing, and manufacturers should be as well to ensure their vehicles are compliant in real-world applications.