193 



with transport from the industrialized Great Lakes area including both the U.S. and the Canadian 

 sides of the border. 



The attached photographs illustrate the median visibility during days with low sulfate concentrations 

 (top) as compared to days with high sulfate concentrations (bottom). Picture pages, in order, are 

 for Chiricahua, Big Bend, Glacier, and Acadia. 



SERVICE POSITION : The Service will continue to analyze data collected in its monitoring 

 network to identify the causes of visibility impairment. 



POSITION SUPPORTED BY : EPA, States, Federal Land Managing Agencies, and members of 

 the scientific community. 



POSITION OPPOSED BY : No one presently, but some industrial representatives may challenge 

 interpretations from time to time. 



FUNDING REQUIREMENTS : In-house staff, approximately $800,000 NPS funds. 



CONTACT : John P. Christiano, Chief, Air Quality Division, National Park Service, P.O. Box 25287 

 Denver, CO 80225-0287 [(303) 969-2070] 



REFERENCES : 



Bresch, J.F., E.R. Reiter, M.A. Klitch, H.K. Iyer, W.C. Malm, K.A. Gebhart. 1986. Origins of sulfur- 

 laden air at national parks in the continental United States. In Visibility Protection - Research and 

 Policy Aspects, Air Pollution Control Association, P.S. Bhardwaja, ed. 



Gebhart, K.A. and W.C. Malm. 1991. Examination of source regions and transport pathways of 

 organic and light absorbing carbon into Remote areas of the United States. Presented at the 84th 

 Annual Meeting of the Air and Waste Management Association, Vancouver, BC, Canada. Paper 

 No. 91-82.4. 



