Measurement of real-world emissions on non-road mobile machinery
Project duration: 2025
Funding: Environmental Agency Austria
Project team: Weller, Nöhrer, Tiesenhausen, Plakolmer, Stadlhofer, Hausberger
The non-road mobile machinery (NRMM) sector includes agricultural vehicles and machinery, construction machinery, hand-held equipment, ships and rail vehicles. Together, these account for approximately 20% of nitrogen oxide emissions and, at 45%, almost half of the exhaust particle mass emissions from the Austrian transport sector[1]. In order to reduce pollutant emissions from NRMM, there are pollutant regulations in place, just as there are for road traffic. The currently valid Stage V regulates not only emissions on the test bench but also, for the first time, emissions in real-world operation with the aid of so-called in-service monitoring tests[2]. In addition, Stage V introduced a limit value for the number of particles, which makes the installation of diesel particulate filters unavoidable[3].
In order to assess the effectiveness of the various regulations on real-world emissions, we were commissioned by the Environment Agency Austria to carry out measurements on 8 NRMMs in real-world operation. The focus was on the most modern machines with emission stages IV and V. When selecting the machines, care was taken to ensure that a wide range of possible machine categories and areas of application were covered and that machines with different operating hours were selected. This allows us to investigate whether increased operating hours have an influence on emission behaviour.
The following figures show how the portable emission measurement system (PEMS) was installed on various machines without restricting real-world operation.
Figure 1: Installation of portable measuring system on various NRMM
Figure 2 shows the preliminary results for NOx and particle number compared to their respective limit values. It can be seen that the randomly selected machines partially comply with the limit values in real operation for both NOx and PN, but some machines exceed them many times over. Although none of the machines displayed an error, the exhaust gas aftertreatment is obviously not functioning properly in all machines in the field.
Figure 2: Installation of portable measuring system on various NRMM
The results also show that increased operating hours can more than double emissions compared to when the machine is new.
In a follow-up project for the Swiss Federal Office for the Environment, these measurement data will be used to create emission factors for the NRMM sector.
[1] M. Schwingshackl, S. Hausberger: Straßenverkehrsemissionen und Emissionen sonstiger mobiler Quellen Österreichs für die Jahre 1990 bis 2023 (OLI2024), prepared on behalf of the Environment Agency Austria. Report Nr. I-36/2024/Schwings EM Inst-24/007/25-670 dated 03.12.2024
[2] ISM tests are only mandatory for machines with a rated power of 56 to 560 kW.
[3] The PN limit value only applies to machines with a rated power of 19 to 560 kW.