A nitric oxide (NO) detector was developed and integrated into the original carbon monoxide (CO) and hydrocarbon (HC) remote sensing system developed by the University of Denver. The system is capable of measuring the CO, HC, and NO exhaust emissions of thousands of on-road vehicles per day. Analysis of a typical field measurement in Denver shows CO, HC, and NO emissions have similar statistics which can be well represented by a gamma distribution. The fraction of NO high emitters tends to increase with age, apparently arising from deterioration of the emissions control system. This paper presents the inverse relationship between NO and either CO or HC emission.
A new remote sensor for measuring on-road carbon monoxide, carbon dioxide, and hydrocarbon exhaust emissions in under 1 s from vehicles passing the sensor is described. The new design adds the capability for measuring exhaust hydrocarbons and eliminates the need for liquid-nitrogen-cooled detectors while improving upon the overall signal to noise. Under typical field operating conditions, sensitivity to 0.05% propane with a precision of 0.014% propane is observed. Two types of water interferences important to the measurement of exhaust hydrocarbons are reported. The water vapor present in all auto exhaust causes a small positive bias dependent on the analytical wavelength chosen. Amuch larger interference is caused by liquid water (often called "steam") plumes seen behind cold vehicles at low temperatures.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.