Remote Sensing of NO and NO2 Emissions from Heavy-Duty Diesel Trucks Using Tunable Diode LasersEPA Grant Number: R824794
Title: Remote Sensing of NO and NO2 Emissions from Heavy-Duty Diesel Trucks Using Tunable Diode Lasers
Investigators: McRae, Gregory J. , Jimenez, Jose-Luis , Kolb, Charles E. , Nelson, David D. , Zahniser, Mark S.
Institution: Massachusetts Institute of Technology , Aerodyne Research Inc.
EPA Project Officer: Chung, Serena
Project Period: October 1, 1995 through September 30, 1998
Project Amount: $388,284
RFA: Air Pollutants (1995) Recipients Lists
Research Category: Air Quality and Air Toxics , Air
Pollution levels frequently exceed federal air quality standards in many urban areas. The formation of such pollutants as ozone is the result of chemical reactions between emissions of nitrogen oxides (NOX), carbon monoxide (CO) and volatile organic compounds (VOCs). Since motor vehicles are a major source of these pollutants the development of cost effective emissions control programs is critically dependent on the ability to quantify the emissions contributions of cars and trucks. Recent advances in remote sensing technology have stimulated the development and demonstration non--dispersive infrared instruments which allow the across-road measurement of exhaust carbon monoxide (CO) emission indices for on-road vehicles, as well as a reasonable approximation of the volatile organic compound (VOC) emission indices. A critical weakness of the present approaches is that they cannot detect emissions of NOX (NO and NO2), the key precursors to photochemical air pollution.
A key thrust of this proposal is to demonstrate, and field test, a new Tunable Infrared Laser Differential Absorption Spectroscopy (TILDAS) air quality monitor that will be capable of determining the NOX emissions from motor vehicles and in particular heavy duty diesel-fueled trucks. The instrument will have the capability to make long path length measurements (>200m) and be able to simultaneously measure nitric oxide (NO), nitrogen dioxide (NO2), and carbon dioxide (CO2). The instrumentation approach proposed in this research has the potential for dramatic improvements in emissions characterization and has been designed in such a way as to be broadly applicable to a wide range of pollutants. In particular, the TILDAS air quality monitoring systems will fill critically needed information gaps in characterizing in-use emissions of NOX from vehicles under actual operating conditions. The technology has the potential to be incorporated into routine monitoring networks and provide more chemical specificity and time resolution than currently available. The specific tasks proposed in this proposal are:
|Task 1:||Verification of the performance of crossroad TILDAS instrument in measuring NO/CO2, NO2/CO2 and NO/NO2 ratios. A key goal is to establish the limits of detection.|
|Task 2:||Development of a mathematical model to estimate the NOX emissions from moving vehicles given as input vehicle characteristics, fuel used, local dispersion and data derived from the TILDAS system.|
|Task 3:||A one week field measurement program will be defined in conjunction with U.S. EPA Air and Energy Engineering Research Laboratory (AEERL).|
|Task 4:||A feasibility study of the potential for absolute determination of emissions by multiple crossroad beam passes.|
|Task 5:||An urban area field measurement program will be carried out at a jointly selected site. Both gasoline-powered and diesel-powered vehicles will be measured in order to obtain representative inventory of NOX emissions under real-world driving conditions.|