Nowhere is presently out of bounds but thanks for the report re: Tynings Barrow Swallet. It's the first report of poor air on Mendip for 2006 summer season - this year has been much better than 2005 so far.
As Les rightly points out there will probably also be poor air in the "usual suspect" places - Cuckoo, White Pit, Honeymead, Little Crapnell and then possibly some of the wet caves where there are often reports - Manor Farm, GB, Swildon's - but so far it's just Tynings.
No doubt we'll hear more on this topic over the next few weeks+