Miniaturized instrument to obtain atmospheric profiles of NO, NOx, and NOy

To assess the effects of regional pollution on the global atmosphere and the effects of global chemical and climate changes on regional air quality, it is necessary to understand the vertical distribution of key trace species including ozone (O3), carbon monoxide (CO), and nitrogen oxides. To validate the observations made from these satellite platforms and to obtain higher vertical and temporal resolution for these species, it is desirable to have in situ instruments suitable for use on commercial aircraft, small aircraft, unmanned aerial vehicles (UAVs), and balloons. This is a proposal to develop a high-sensitivity, miniaturized NO instrument and appropriate converters to measure NOx (NO+NO2), and NOy (sum of reactive nitrogen) on these platforms. The instrument will be based on the proven NO+O3 chemiluminescence reaction. Miniaturization will be accomplished by using an avalanche photodiode photon-counting module coupled with a compound parabolic concentrator to optimize collection of photons. Expected sensitivity of the system will be 10 to 50 parts per trillion by volume (pptv) for 10-second integration. The Phase I work will focus on design and testing of the photon-collection system. Phase II work will include design and fabrication of a miniaturized instrument and performance evaluation.