How reassuring are risk comparisons to pollution standards and emission limits?

Pollutant emissions or ambient levels are often justified by reference to a higher benchmark, such as a public health standard or permit limit. However, does this risk comparison persuade the public audiences to whom it is frequently directed that such pollution levels are "acceptable"? A substantial proportion of people living within one mile of New Jersey's industrial facilities, perhaps as much as half, is indeed reassured by a comparison to such benchmarks. Positive attitudes toward discharge limits were linked to speaking English at home; positive attitudes toward drinking water standards were associated with seeing local benefits of industry as outweighing its risks, not speaking English, and relative youth (49 years old or less). Three scenarios involving drinking water contamination varied pre- and post-treatment levels of the pollutant, though all post-treatment levels were below the standard. In all cases great concern was expressed, with no significant differences across scenarios; net benefits, being white, and non-English speaking were linked to lower concern. Relative trust seems a better explanation of different attitudes toward benchmark comparisons than varying levels of knowledge, but both hypotheses have drawbacks that merit further testing. These results imply that people with negative views of industry or government, the ones officials might most wish to reassure, will tend to doubt that regulatory benchmarks offer a valid risk comparison.