Simultaneous measurement of NO and NO(2) by dual-wavelength quantum cascade laser spectroscopy.

The concept of a multi-wavelength quantum cascade laser emitting at two or more spectrally well-separated wavelengths is highly appealing for applied spectroscopy, as it allows detecting several species with compact and cost-efficient optical setups. Here we present a practical realization of such a dual-wavelength setup, which is based on a room-temperature quantum cascade laser emitting single-mode at 1600 cm and 1900 cm and is thus well-suited for simultaneous NO and NO detection. Operated in a time-division multiplexed mode, our spectrometer reaches detection limits of 0.

The cold start emissions of light-duty-vehicle fleets: a simplified physics-based model for the estimation of CO₂ and pollutants.

The emissions from hot driving conditions, in which the exhaust-after-treatment systems are working properly, continue to decrease, which is why the emissions of cold starts have gained in importance. Traffic emission models are used to estimate and predict vehicle fleet emissions and the air quality of countries, regions, cities, etc. In addition to the statistical input of fleet activities, these models are mostly based on the use of separate emission sub-models for hot driving and cold start driving.