Special Study - WHITEX
The Winter Haze Intensive
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This study was designed to evaluate the feasibility of attributing single
point source emissions to visibility impairment in Grand Canyon National Park. WHITEX was conducted
during a six week period in January and February 1987. During this time, an
artificial tracer, deuterated methane (CD4), was released from the NGS at Page,
AZ near the eastern end of the Grand Canyon. Aerosol, optical, tracer, and other
properties were measured at Hopi Point (on the south rim of the Grand Canyon)
and other locations. Using the tracer, 70% to 80% of the sulfate at Hopi Point
under certain meteorological conditions in the winter was attributed to the NGS (Malm et al., 1989b). Some controversy arose from this attribution since the
ratio of the CD4 emissions rate to power plant load was not maintained at a
stable value (Markowski, 1992).
In addition, while the measurement of CD4
concentrations is quite precise, the analytical costs are high. As a result,
only a fraction of the samples collected were ever analyzed. WHITEX demonstrated
the potential of tracer techniques for single source attribution. The study also
showed that maintaining a stable tracer/power load emission ratio and using a
low cost tracer analytical technique could improve the quality of the source
Final Report: Winter Haze
Intensive Tracer Experiment
peer reviewed articles from the AWMA/EPA Visibility & Fine Particles
Specialty Conference held in Estes Park, Colorado, October 1989.
Issues Associated with the WHITEX. Farber et al.
Orthogonal Function Analysis of the Particulate Sulfate Concentrations
Measured During WHITEX. Gebhart et al.
Investigation of the Size Distributions of Particulate Sulfate
Concentrations Measured During WHITEX. Gebhart and Malm.
of a Differential Mass Balance Model to Attribute Sulfate Haze in the
Southwest. Latimer et al.
Oxides and Nitrogen Oxy-Acids Present during the WHITEX Study as
Determined using Filter Pack and Diffusion Denuder Sampling Systems.
Lewis et al.
of a Variety of Receptor Modeling Techniques. Malm et al.
of Tracer Mass Balance Regression to WHITEX Data. Malm et
Environmental Protection Agency's Visibility Protection
Program: Ten Years of Regulatory Development. Scott and
Attribution During WHITEX: A Modeling Study. Stocker and Pielke.