Across North America Tracer Experiment (ANATEX). Volume 4, Quality assurance of ground-level samplers and quality assessment of EML analysis of surface samples.

摘要

This report is the fourth in a series of interagency reports of the Across North America Tracer Experiment (ANATEX). ANATEX was a series of 33 tracer releases, conducted from January to March 1987, to simulate the atmospheric transport and dispersion of pollutants to distances of 3000 km. Different tracers were simultaneously released into the atmosphere from two release sites, Glasgow, MT, and St. Cloud, MN. Each site is separated by a distance of (approximately)1000 km. The tracers were released for a period of 3 h, every 2.5 days, over an 82- to 83-day period. Programmable atmospheric tracer samplers were emplaced at 77 primary ground-level sampling stations, located in arcs ranging from 500 to 3000 km from the Montana release site. Ground-level air samples of 24-h duration were continuously collected at each station over the 83-day release period. Additional samplers were co-located at nine stations to provide duplicate samples for quality assessment purposes. After the experimental phase was completed, additional daily samples were collected at the Environmental Measurements Laboratory's (EML) Chester, NJ, Regional Baseline Station to verify the ambient background concentration of each tracer and to provide samples for laboratory intercomparison analyses. Presented here are EML's modifications to improve the surface samplers, as well as the quality assurance procedures used for their preparation. In addition, estimates of precision of sampling and analysis for the surface samples analyzed by EML are presented. The effect of contaminants on the quality of analytical results is also discussed. 15 refs., 13 figs., 5 tabs.