A multi-pronged approach to strengthen diesel vehicle emission monitoring

Abstract

Vehicle exhaust emissions have become a major source of air pollutants in China, especially from diesel vehicles, which are the main contributors to the total nitrogen oxide (NOx) and particulate matter (PM) emissions from road vehicles. To combat these emissions, China is setting up an integrated vehicle emission monitoring system aiming at organically combining periodic inspections, remote sensing, on-board diagnostics and roadside inspections. Multiple measures, which include vehicle emission in-use compliance tests using portable emission measurement systems (PEMSs), remote OBD monitoring, periodic inspection of NOx emissions and remote emission sensing detection, are taken to monitor the pollutant emissions from diesel vehicles. In this study, all these methods were used to measure the exhaust pollutant emissions of in-use diesel vehicles, to evaluate the trends in real-world emission reductions along with the progress of emission control technologies and emission standards in China.