Measuring On-Road Vehicle Emissions with Multiple Instruments Including Remote Sensing

Robin Smit,Phil Kingston

doi:10.3390/atmos10090516

Abstract

The objective of this paper is to use remote sensing to measure on-road emissions and to examine the impact and usefulness of additional measurement devices at three sites. Supplementing remote sensing device (RSD) equipment with additional equipment increased the capture rate by almost 10%. Post-processing of raw data is essential to obtain useful and accurate information. A method is presented to identify vehicles with excessive emission levels (high emitters). First, an anomaly detection method is applied, followed by identification of cold start operating conditions using infrared vehicle profiles. Using this method, 0.6% of the vehicles in the full (enhanced) RSD data were identified as high emitters, of which 35% are likely in cold start mode where emissions typically stabilize to low hot running emission levels within a few minutes. Analysis of NOx RSD data confirms that poor real-world NOx performance of Euro 4/5 light-duty diesel vehicles observed around the world is also evident in Australian measurements. This research suggests that the continued dieselisation in Australia, in particular under the current Euro 5 emission standards and the more stringent NO2 air quality criteria expected in 2020 and 2025, could potentially result in local air quality issues near busy roads.

Highlights

Motor vehicles are a major source of air pollution and greenhouse gas (GHG) emissions in urban areas around the world
The reader is referred to the following papers: (1) detecting cold start vehicles using thermal imaging and Bluetooth units [7]
This paper discussed and presented selected results from a short but comprehensive on-road emission measurement program conducted in Brisbane, Australia

Summary

Introduction

Motor vehicles are a major source of air pollution and greenhouse gas (GHG) emissions in urban areas around the world. The close proximity of motor vehicles to the general population makes this a relevant source from an exposure and health perspective [1]. A comprehensive measurement of vehicle emissions in urban networks is cost-prohibitive due to the large number of vehicles that operate on roads with different emission profiles, large spatial and temporal variability in vehicle activity, and a range of real-world factors that influence emission levels [2]. Several methods are used to measure vehicle emissions, such as on-board emission measurements (PEMS), remote sensing, near-road air quality measurements, and tunnel studies. This study took a step further than ‘conventional’ remote sensing programs, with the specific aim to examine data accuracy, enhance data capture rates, and potentially address

Objectives

Methods

Results

Conclusion