I think higher pollution is acceptable, especially given that most of the science behind the "harm" of pollution at levels we are debating, in the US, is weak.
For instance, the EPA declared diesel exhaust a "likely" carcinogen, even though there have been alot of studies disputing that claim, and many studies showing linkage to lung cancer have confounding factors (such as smoking... ie, people working in blue collar jobs exposed to diesel exhaust are also more likely to smoke). Likewise, there have been all sorts of bad stories about all sorts of chemicals that are suppossedly "bad for you", but years later, who knows, they may be exonerated (like saccharin, which now has been shown to not be a likely human carcinogen).
It's sad that environmentalism now days is obsessed with things as trivial as what is essentially "trace" pollutants, when there are people out there suffering and dying from real problems like malaria and malnutrition. The US has some of the cleanest air in the world, but some people are still not happy with that. The planet and humans in general have far bigger problems than if exhaust or trace chemicals just might up your cancer risk by a marginal amount.
