In September 2011, I spent about 10 days in the Black Hills and Badlands areas. Then I drove east across the state on I-90.
In late October 2011, I spent the night in Sioux Falls and then drove south on I-29 to Iowa.
BLACK HILLS AREA: 5 (EXCELLENT), with exceptions.
I was camping for most of my time in the Black Hills in the KOA in Hot Springs, which was pleasant and felt good to me. Hot Springs has an interesting archaeological dig site (open to the public) for wooly mammoths as well as a "cool springs" pool (something like 90 degrees). Both of these were indoor attractions but felt good to me. The outdoor air was great. (5-EXCELLENT)
Nearby Wind Cave National Park was pleasant and felt great. I toured the caves at Wind Cave and Jewel Cave, and felt great in both of them. (5-EXCELLENT)
(Interestingly, Jewel Cave had some trees burned down on its property but they felt fine. My understanding from talking to the rangers is that they don't use chemicals for fires there because they're afraid it will have a negative impact on the cave!)
Keystone (near Mt. Rushmore) felt great as well. (5-EXCELLENT)
Rapid City is a fairly nice town and felt fine. (4-GOOD)
The one place here that I felt bad was in Custer State Park. They periodically do planned burns and apparently use fire retardants during them. (There even was a photo of someone carrying a fire retardant tank for one of these burns in the photos in the exhibit in the visitors' center.) This seemed to be a particularly heavy concentration of the toxin that I'd found in certain other places associated with fire retardants (Santa Fe, Tucson, Glacier National Park, Big Sur). It wasn't the "worst toxin for me," but it was concentrated enough that it was a real problem anyway. Both my husband (a moderate Moldie) and I got quite sick, and the car continued to bother me for a few more days. (Unfortunately, Custer is a very large park and it was difficult to make a quick escape.) (1-AWFUL)
REST OF SOUTHWESTERN SOUTH DAKOTA: 3 (FAIR)
I spent a couple of days in the other parts of SW South Dakota, much of which is Sioux (Lakota) Indian Reservation territory. This included a night at the campground at Badlands National Park, a night at a KOA on I-90, and a visit to the kitschy-touristy Wall Drugs.
There's something weird about this area. Neither my husband nor I felt good there. He felt anxious and unhappy, and we both were pretty irritable. Our sense was that the people who lived in the area were irritable as well.
I'm not sure whether this "weirdness" had anything to do with toxins. My husband, who is less convinced than I that toxic exposures are the only cause of his emotional reactions, made a case that the land was "haunted" as a result of the unhappy events of Wounded Knee and other slaughters of Indians. And even before the late 1880s, the Badlands had a reputation as being, well, "bad." The Sioux were a particularly violent tribe, and there's a passage in one of the Laura Ingalls Wilder books about a group of pioneers reporting a particularly emotionally discomfiting experience passing through.
So I'm not sure what to say. I still suspect fire retardants used in Badlands National Park were the cause of my own negative emotions. (The ranger said that they are sometimes used there.) But maybe there's something metaphysical going on too. I'm not eager to go back to this area in general, regardless.
SOUTHEASTERN SOUTH DAKOTA: 5 (EXCELLENT)
Going east, I-90 from about Murdo (south of Pierre) felt good to me. I spent the night in a campground near Mitchell, which felt perfectly good to me. (5-EXCELLENT)
I detoured to visit De Smet, which is where Laura Ingalls Wilder lived during her adolescent and early adult years. I visited the houses in town where Laura lived and spent the night in my RV on their homestead just outside of town. The air was absolutely terrific, and as a tourist attraction it was a good stop. Highly recommended. (5-EXCELLENT)
travel.nytimes.com/2011/08/07/travel/at-laura-ingalls-wilder-sites-trading-tiaras-for-calico.html?pagewanted=allFrom De Smet, I drove east to I-29 and then south to Sioux Falls. This part of the drive did not feel as good as De Smet, but I didn't stay long enough to be able to give it any sort of accurate rating.
SIOUX FALLS: 3 (FAIR)
I spent a couple of nights in Sioux Falls in mid September and then one more night in late October. Even in mid September, I could feel a tinge of "the worst toxin for me" in the air on overcast days. In late October, it didn't feel great even on a sunny day, and felt pretty worrisome when the skies got overcast. I did better in Chicago than there. "Fair" may be being generous. So I'm not particularly eager to go back.
Driving south on I-29, the air felt good to me starting at about 10 miles south of the city until close to the Iowa border (approaching Sioux City). (4-GOOD)