PEMS Testing

Portable Emissions Measurement Systems (PEMS) Testing

Emissions Analytics provides independent PEMS testing services to measure real-world emissions from vehicles and machinery. Our work supports Stage V ISM, RDE and ISC testing, research programmes, benchmarking, and environmental impact analysis across a range of powertrain and operating conditions.

Portable Emissions Measurement Systems (PEMS) testing is a method for measuring vehicle emissions in real-world operating conditions, rather than in a controlled laboratory environment.

A PEMS unit is installed directly onto a vehicle or machine, allowing emissions to be measured while it is driven on the road or operated in the field. This enables the capture of data across a wide range of conditions, including different speeds, loads, temperatures, terrains, and driving behaviours.

Unlike laboratory testing, which follows fixed cycles, PEMS testing reflects how vehicles and machinery are actually used. This makes it a critical tool for understanding real-world emissions performance, supporting both regulatory programmes and independent research.

What is PEMS testing?

Emissions Analytics provides independent PEMS testing to measure real-world emissions across a broad range of vehicles and operating environments.

Regulatory testing is conducted outside of laboratory constraints, allowing emissions to be assessed under genuine driving and usage conditions. This includes variations in route, load, duty cycle, and environmental factors, all of which can significantly influence emissions outcomes.

As an independent organisation, Emissions Analytics focuses on generating objective, data-led insights. This supports manufacturers, regulators, and other stakeholders in understanding how emissions performance translates from controlled environments into real-world operation.

The emphasis is not only on measurement, but on interpretation. By analysing real-world emissions data, Emissions Analytics helps identify patterns, discrepancies, and areas where performance differs from expectations.

Independent PEMS testing for real-world emissions

PEMS regulatory testing plays a central role in both Real Driving Emissions (RDE) and In-Service Conformity (ISC) regulatory testing programmes.

RDE testing is used to assess vehicle emissions under normal driving conditions, providing insight into how emissions perform under real-world conditions and beyond the laboratory. It captures emissions across a defined range of real-world scenarios, providing a more representative view of performance.

ISC testing focuses on vehicles already in use, evaluating whether emissions performance remains compliant over time. This is particularly important for understanding how ageing, maintenance, and real-world usage affect emissions.

Emissions Analytics supports these applications through independent PEMS testing, providing data that can be used for regulatory assessment, benchmarking, and research. We provide Euro VI ISC (in-service conformity) for commercial vehicles and Stage V ISM (in-service monitoring) for non-road applications. This includes both formal regulatory testing programmes and broader investigative work into real-world emissions behaviour. 

Stage V ISM (In-Service Monitoring) is the EU requirement for non-road engines to have their emissions measured during real-world operation after they are in use, rather than only during lab certification. Using PEMS equipment, manufacturers must demonstrate that pollutants like NOx, CO, and particulate emissions remain within regulatory limits under actual working conditions, ensuring ongoing compliance, durability of emissions control systems, and the absence of defeat strategies outside controlled test cycles.

Stage V ISM, RDE and ISC testing applications

Emissions Analytics conducts PEMS testing across a wide range of vehicle types and machinery.

This includes passenger cars, commercial vehicles, and non-road mobile machinery, reflecting the diversity of real-world emissions sources. Regulatory testing can be carried out across different fuel types, powertrains, and operating conditions.

The approach is designed to be flexible, allowing regulatory testing to be tailored to specific use cases. This may include urban, rural, or motorway driving, as well as more specialized duty cycles for off-highway equipment.

By applying consistent measurement techniques across different applications, Emissions Analytics enables direct comparison of emissions performance between vehicles, technologies, and use cases.

Vehicle and machinery testing capabilities

Independent emissions testing provides a critical layer of transparency in understanding real-world performance.

Laboratory testing and manufacturer data offer important insights, but they do not always capture the full range of conditions encountered in everyday use. Independent PEMS testing helps bridge that gap by measuring emissions directly in real-world environments.

This independence allows for objective evaluation, free from commercial or regulatory bias. It supports more informed decision-making for manufacturers, policymakers, and researchers, particularly in areas where emissions performance is complex or evolving.

In practice, this means identifying discrepancies between expected and observed performance, improving understanding of emissions behaviour, and contributing to more robust and reliable data across the industry.

Why independent testing matters

FAQ questions

  • Portable Emissions Measurement Systems (PEMS) testing is a method of measuring vehicle or machinery emissions in real-world conditions.

    A PEMS unit is fitted directly to a vehicle or machine, allowing emissions to be recorded while it is driven or operated. This enables measurement across a wide range of real-world scenarios, including different speeds, loads, terrains, and environmental conditions.

    PEMS testing is used to understand how emissions perform outside laboratory environments.

  • Portable Emissions Measurement Systems (PEMS) are mobile devices used to measure emissions directly from vehicles or machinery during operation.

    “Portable” refers to the ability to install the system on a vehicle or machine.

    “Emissions Measurement” refers to the monitoring of pollutants such as gases and particles.

    “Systems” reflects that PEMS combines multiple instruments to capture and record emissions data in real time.

  • The main difference is where and how the testing takes place.

    Laboratory emissions testing is conducted in controlled environments using fixed test cycles. This ensures repeatability but limits the range of conditions being assessed.

    PEMS testing is carried out in real-world conditions, where variables such as driving behaviour, terrain, temperature, and load can vary significantly. This allows emissions to be measured under actual operating conditions.

    As a result, PEMS testing provides insight into real-world emissions performance, while laboratory testing provides standardised, comparable results.

  • Emissions Analytics conducts independent PEMS testing that is closely aligned with Real Driving Emissions (RDE) approaches.

    This includes measuring emissions under real-world driving conditions similar to those considered in RDE frameworks. The focus is on understanding how emissions behave outside laboratory environments, rather than conducting formal regulatory approval testing.

  • Stage V In-Service Conformity (ISC) testing is typically carried out using Portable Emissions Measurement Systems (PEMS) to assess how machinery performs under real-world operating conditions over time.

    To undertake ISC testing, organisations usually work with a testing provider to measure emissions from equipment in use, capturing data across representative duty cycles, loads, and environments. This helps evaluate whether emissions performance remains consistent with expectations outside of initial approval testing.

    Emissions Analytics conducts independent PEMS testing that can be used to assess real-world emissions performance in line with Stage V ISC principles.

    Testing focuses on measuring emissions directly from machinery during operation, providing insight into how performance varies in practice, including the effects of usage, environment, and ageing.

  • Emissions Analytics carries out independent PEMS testing that can be used to examine emissions performance over time, in line with the principles of In-Service Conformity (ISC).

    Testing focuses on how emissions vary in real-world use, including the effects of ageing, maintenance, and operating conditions. This provides insight into how vehicles and machinery perform beyond initial testing.

  • PEMS testing in Europe is carried out by a range of organisations, including certification laboratories, engineering consultancies, and independent testing organisations.

    Certification laboratories focus on regulatory compliance.

    Engineering consultancies support development and optimisation.

    Independent organisations focus on measuring and analysing real-world emissions performance.

    Emissions Analytics is an independent testing organisation specialising in real-world PEMS measurement across vehicles and machinery.

  • Yes. PEMS can be used to measure emissions from non-road mobile machinery and off-highway equipment.

    This includes machinery operating under variable loads and duty cycles, where laboratory testing may not fully represent real-world conditions. PEMS allows emissions to be measured directly during operation in the field.

  • Independent PEMS testing provides a clearer view of real-world emissions performance.

    Unlike regulatory testing, which follows defined frameworks, or development testing, which is often focused on optimisation, independent testing is designed to observe how emissions behave in practice.

    By measuring emissions across a wider range of real-world conditions, independent PEMS testing helps identify differences between expected and observed performance, providing a more complete understanding of emissions behaviour.