presented by Donald H. Stedman, University of Denver Dept. of Chemistry and Biochemistry
Motor vehicles emit a range of interesting pollutants. Many pollutants can be measured by means of spectroscopic techniques. If the combination of spectroscopic speed and sensitivity is such that the exhaust can be monitored in a ten meter optical beam at 100 Hz, then direct monitoring is possible as the vehicle drives by. As long as a concurrent measurement of CO 2 is also carried out, then the measured emissions can be cast as emissions per kg of fuel. This is a useful parameter to determine the efficiency of the engine and to determine an emission inventory of the pollutant based upon fuel sales (usually available from the tax authorities). We do this routinely in the I.R. for CO, CO 2, and generic hydrocarbons (the C-H stretch at 3.4μ). We monitor NO using the (0-0) gamma band at 228 nm in the UV. Recently we have added the capability to monitor NH 3 and SO 2 farther into the UV and NO 2 at 430 nm (almost in the visible). If we are willing to go beside the road in the right wind conditions, perhaps we can slow down our response to 1 Hz and still monitor pollutant plumes from individual identified vehicles. With this technique we might be able to monitor speciated hydrocarbons (for instance with PTRMS) or formaldehyde with TDLAS or particle size distribution and number (with a fast response CN counter) or particle opacity with an aethalometer or a photoacoustic monitor. A challenge for any of these added techniques will be the fact that a good remote sensing location will net about 10,000 vehicles in a day’s work and data analysis needs to be quite streamlined.
Seminar is from
9:30 am to 10:30 am in FL2 Room 1022
on Tuesday, May 17, 2005.
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