Miniature Nitrogen Dioxide Trace Gas Sensor for In Situ Atmospheric Measurements

Nitrogen dioxide (NO2) poses a health risk, particularly for children and individuals with respiratory issues like asthma. It is produced by a variety of sources, including vehicles, industrial plants, and appliances in homes. To better regulate this toxic pollutant, it is important to know where the sources are and how it is dispersed in the atmosphere. Current accounting for NO2 sources and dispersal is done by a combination of measurements and modeling, in which remote sensing from satellites provides data that is used to validate models of chemical transport. However, these models are far from certain and a limiting factor is the interpretation of the satellite data, which requires knowledge of the vertical distribution of NO2 in the troposphere since the satellite measurements do not, by themselves, provide this. Thus, there is a need for in situ measurements of NO2 from airborne platforms on a wide scale. Current sensors are costly and often not suitable for use onboard small aircraft, such as unmanned aerial vehicles, which would help enable widespread measurements. A miniaturized low-cost instrument is proposed for sensitive measurements of NO2 based on laser absorption that will help enable extended in situ measurements that will provide accurate high-fidelity data that is needed to properly interpret satellite measurements and validate chemical transport models. Data obtained with this sensor is expected to lead to an improved accounting of NO2 sources and distribution in the atmosphere. In the proposed effort, we will develop the sensor and confirm its accuracy, which is projected to be significantly better than existing sensors at a lower per unit cost, thus enabling widespread deployment. A compact, affordable high precision sensor for NO2 would find immediate customers in the air pollution research community, and future versions of the technology should be within the reach of general consumers, opening up a new market for home NO2 monitoring.