How do dogs react to smelling Ethanethiol in a safe but high concentration?

If humans can detect ethanethiol (the smelliest substance known to man, added to natural gas to make it smell) at a concentration of 0.2 parts per billion of air, how would an animal with highly sensitive olfactory receptors react (such as a dog - 100,000 to a million times more sensitive than a human's)? Anyone able to make an educated guess? Anyone able to find out?