28 Jul 2023
 | 28 Jul 2023

Large-scale automated emission measurement of individual vehicles with point sampling

Markus Knoll, Martin Penz, Hannes Juchem, Christina Schmidt, Denis Pöhler, and Alexander Bergmann

Abstract. Currently, emissions from internal combustion vehicles are not properly monitored throughout their life cycle. In particular, a small share (< 20 %) of poorly maintained or tampered vehicles are responsible for the majority (60–90 %) of traffic-related emissions. Remote emission sensing (RES) is a method used for screening emissions from a large number of in-use vehicles. Commercial open-path RES systems are capable of providing emission factors for many gaseous compounds, but they are less accurate and reliable for particulate matter (PM). Point sampling (PS) is an extractive RES method where a portion of the exhaust is sampled and then analyzed. So far, PS studies have been conducted predominantly on a rather small scale and have mainly analyzed heavy duty vehicles (HDV), which have high exhaust flow rates. In this work, we present a comprehensive PS system that can be used for large-scale screening of PM and gas emissions, largely independent of the vehicle type. The developed data analysis framework is capable of processing data from 1,000s of vehicles. The core of the data analysis is our peak detection algorithm (TUG-PDA), which determines and separates emissions down to a spacing of just a few seconds between vehicles. We present a detailed evaluation of the main influencing factors on PS measurements by using about 100,000 vehicle records collected from several measurement locations, mainly in urban areas. We show the capability of the emission screening by providing real-world black carbon (BC), particle number (PN) and NOx emission trends for various vehicle categories such as diesel and petrol passenger cars or HDVs. Comparisons with open-path RES and PS studies show overall good agreement and demonstrate the applicability even for the latest Euro emission standards, where current open-path RES systems reach their limits.

Markus Knoll et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-1279', Anonymous Referee #1, 28 Aug 2023
  • RC2: 'Comment on egusphere-2023-1279', Anonymous Referee #2, 06 Sep 2023

Markus Knoll et al.

Markus Knoll et al.


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Short summary
Exhaust emissions from combustion-based vehicles are negatively affecting human health and our environment. In particular, a small share (< 20 %) of poorly maintained or tampered vehicles are responsible for the majority (60–90 %) of traffic-related emissions. The emissions from vehicles are currently not properly monitored during their lifetime. We present a roadside measurement technique, called point sampling, which can be used to monitor vehicle emissions throughout their life cycle.