Slide 7 of 31
Notes:
While US (or North American) patterns of many air pollutants are similar to those for sulfur deposition or sulfate concentration, other pollutants exhibit very different spatial patterns.
In this case we see monthly mean Arsenic concentrations from the combined IMPROVE and NEPART networks for December, 1989.
Note that attempted measurements were conducted at all sites (small white circles), but values at many sites were below detection limits. Note also, that these networks include only rural/remote “background” sites, and that the spatial coverage of measurement sites is sparse in some regions.
The highest concentrations of fine particle arsenic were observed in an area of the Southwest - particularly at Chiracahua National Park in New Mexico. High concentrations were also observed in the Northeast - particularly at Underhill Vermont, on the side of Mt. Mansfield.
These high Northeastern concentrations were of particular concern in Vermont - from a human health perspective, as arsenic is a suspected carcinogen - and also from a regulatory perspective, as the concentrations exceeded the State’s ambient standards for arsenic at a remote background site. Vermont’s hazardous air contaminant regulations required a determination that the impact from any new source, combined with background levels, would not exceed standards.
