Relatively speaking, you're correct that we enjoy less density of poison ivy than other parts of the US. Generally, poison ivy grows east of the Rocky Mountains, poison oak west of the Rocky Mountains, and poison sumac in the southeastern United States. Poison Oak has two species, one of which grows along the Pacific coast from WA down to Mexico. There are two closely related species of poison Ivy, and grows almost everywhere in the United States except Alaska, Hawaii, Nevada and parts of California, but rarely at altitudes above 4,000 ft. It often grows along rivers, lake fronts, and ocean beaches, but not in the rainforests of WA or OR. Like I said earlier, poison sumac grows mainly east of the Mississippi River.
I grew up on the farm in IL and have had many unpleasant experiences with Ivy & Oak. If you know where you commonly encounter that stuff while dozing, then I recommend wearing a mask of some sort. The allergenic oil (urushiol) can be carried in the dust just as it does in smoke during burning. Inhaling the urushiol will at the very least cause lung irritation and some have had such serious reactions internally that it's been fatal to them.
Interestingly, only humans have allergic reactions to urushiol, some much more than others. The oil is what gets us. Our animal's fur, our clothes, tools, etc. is where we keep recontacting with the oil even though we're far from the plants. That's why it's so important to throughly wash everything in hot sudsy water to remove the oil. Unfortunately, once the urushiol gets in contact with our skin it bonds with the skin and we're along for the ride. Treating the itch is all we can do at that point.
Hope this helps. Good luck and get that mask. (and long sleeve shirt etc.) UGH....I hate this stuff.
