Nitrogen dioxide, sulfur dioxide, and ammonia detector for remote sensing of vehicle emissions

A remote sensor for measuring on-road vehicles passing the sensor in real time is described. This sensor expands upon previous technology that measured carbon monoxide, carbon dioxide, and exhaust hydrocarbons in the IR and nitric oxide in the UV. The design adds the capability to measure nitrogen dioxide in the UV with one spectrometer and to measure SO2 and NH3 along with NO in a second UV spectrometer. With these units operating side by side, the major mobile source precursors to secondary aerosol production can be measured simultaneously and in real time. Detection limits for NO2, SO2, and NH3 are 1.2, 0.72, and 0.78 g pollutant per kilogram of fuel, respectively.