Measurement of exhaust emissions from in-use vehicles is key to any effective system for controlling air pollution in the transportation sector. The best-known method of in-use vehicle emissions testing employs a portable emissions measurement system, or PEMS. While PEMS is an essential tool for researchers and regulators, it is not ideally suited to all purposes.
Remote sensing as a means of measuring motor vehicle emissions is less well known, though it is a well-established research technique in that area as well as others, and like PEMS has been successfully deployed by vehicle emissions regulators. Compared to PEMS testing it is less expensive in terms of both time and money, and also less unobtrusive, which makes it difficult if not impossible to cheat. Deployed together, PEMS and remote sensing can produce a more precise and detailed understanding of not only pollutant emissions from on-road transport but also policy performance.
This briefing is a concise introduction to the use of remote sensing in regulating and controlling pollution from on-road vehicles.