The American Society for Testing and Materials (ASTM) is an independent organization devoted to the development of standards.

American Society for Testing and Materials

https://research.birmingham.ac.uk/portal/files/11961623/Estimation_of_the_Contribution_of_Road_Traffic_Emissions_V3_PostPrint.pdf

Estimation of the contribution of road traffic emissions to particulate matter concentrations from field measurements: A review

Traffic-related sources have been recognized as a significant contributor of particulate matter particularly within major cities. Exhaust and non-exhaust traffic-related sources are estimated to contribute almost equally to traffic-related PM10 emissions. Non-exhaust particles can be generated either from non-exhaust sources such as brake, tyre, clutch and road surface wear or already exist in the form of deposited material at the roadside and become resuspended due to traffic-induced turbulence. Among non-exhaust sources, brake wear can be a significant particulate matter (PM) contributor, particularly within areas with high traffic density and braking frequency. Studies mention that in urban environments, brake wear can contribute up to 55 % by mass to total non-exhaust traffic-related PM10 emissions and up to 21 % by mass to total traffic-related PM10 emissions, while in freeways, this contribution is lower due to lower braking frequency. As exhaust emissions control become stricter, relative contributions of non-exhaust sources—and therefore brake wear—to traffic-related emissions will become more significant and will raise discussions on possible regulatory needs. The aim of the present literature review study is to present the state-of-the-art of the different aspects regarding PM resulting from brake wear and provide all the necessary information in terms of importance, physicochemical characteristics, emission factors and possible health effects.

/pdf/brake-wear-particle-emissions-a-review-4aty842zii.pdf

Brake wear particle emissions: a review

https://www.ermes-group.eu/web/system/files/filedepot/10/2013-JRC-Road-vehicle-emission-factors-development-A-review.pdf

Road vehicle emission factors development: A review

https://cyberleninka.org/article/n/1481718.pdf

Fuel consumption and CO2 emissions from passenger cars in Europe – Laboratory versus real-world emissions

In 2011, the European Commission introduced a limit for nonvolatile particle number (PN) emissions >23 nm from light-duty (LD) vehicles and the stated intent is to implement similar legislation for on-road heavy-duty (HD) engines at the next legislative stage. This paper reviews the recent literature regarding the operation-dependent emission of PN from LD vehicles and HD engines, and the measurement procedure used for regulatory purposes. The repeatability of the PN method is of the order of 5% and higher scatter of the results can easily be explained by the effect of the vehicles or the aftertreatment devices on the PN emissions (e.g., the fill state of the diesel particulate filters). Reproducibility remains an issue since it may exceed 30%. These high-variability levels are mainly associated with calibration uncertainties of the PN instruments. Correlation measurements between the full-flow dilution tunnels (constant-volume samplers, CVS) and the proportional partial-flow dilution systems (PFDS) showe...

https://www.tandfonline.com/doi/pdf/10.1080/02786826.2012.661103

Measurement of Automotive Nonvolatile Particle Number Emissions within the European Legislative Framework: A Review

Use of portable emissions measurement system (PEMS) for the development and validation of passenger car emission factors

Development and review of Euro 5 passenger car emission factors based on experimental results over various driving cycles

The particle measurement programme (PMP) used a particle measurement system (reference system (RS)) to quantify the particle number emissions of several vehicles. The RS was circulated around several laboratories to represent an internal standard. During the exercise dilution factors, losses and volatile removal efficiencies of the RS were regularly checked. In parallel with the RS, some labs employed their own particle measurement systems (lab systems (LS)) to determine the emissions of the same test vehicles. Comparisons between results from the RS and the LS showed that several different instruments were capable of measuring particle number emissions to within ±15% across an emission range of four orders of magnitude. Real-time emission patterns also correlated well in most cases. However, larger differences were observed when dilution factors and losses were not accurately determined and subjected to correction. Equivalence between measurement systems can be achieved once calibration and validation procedures are standardized for both manufacturers and users.

http://iopscience.iop.org/article/10.1088/0957-0233/19/9/095401/pdf

Panagiota Dilara

Papers

Road vehicle emission factors development: A review

Measurement of Automotive Nonvolatile Particle Number Emissions within the European Legislative Framework: A Review

Use of portable emissions measurement system (PEMS) for the development and validation of passenger car emission factors

Development and review of Euro 5 passenger car emission factors based on experimental results over various driving cycles

Particle measurement programme (PMP) light-duty inter-laboratory exercise: comparison of different particle number measurement systems