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Mapping NH3, N2O and CO Emissions Using a Mobile Open-path Sensor

Speaker: Kang Sun, Graduate Student
Series: EEWR Brown Bag Seminars
Location: Engineering Quad E225
Date/Time: Friday, November 16, 2012, 12:00 p.m. - 1:00 p.m.

Abstract:

Ammonia (NH3) is a key precursor to atmospheric fine particulate matters, with strong implications for regional air quality and global climate change. Nitrous oxide (N2O) is the third most important anthropogenic greenhouse gas with ~120 years lifetime and the dominant ozone depleting substance. The overall atmospheric budget of both ammonia and N2O are poorly quantified. However, existing studies suggest that traffic exhaust may provide significant amounts of ammonia and N2O in urban area. To date, no significant regulatory effort has been made to control ammonia and N2O emissions from vehicles.

To capture the spatial and temporal variation of ammonia and N2O emissions, we have developed mobile open-path sensors for simultaneous ammonia, N2O, and CO measurements using Quantum Cascade Lasers (QCLs). CO is widely used as a tracer for combustion processes and therefore can help distinguish between agricultural sources and combustion sources of ammonia and N2O. The concurrent CO measurement also enables real-time calculation of the NH3:CO and N2O:CO emission ratios. Roadside measurements at North Garage characterized the NH3, N2O and CO emissions from commuters in the E-Quad. On-road measurements have also been performed continuously from the Midwest to Princeton and in local areas around Princeton. Emissions from urban areas, tunnels, highways, and livestock farms are characterized.