“Pura vida!” our dive guide, Sergio, exclaimed with a relaxed smile. Eight dive buddies, Sergio, and I just had an incredible experience: A 35-foot-long whale shark swam a few feet over our heads at one of the better-known dive sites at Cocos Island, Costa Rica. It silently came and went, seemingly carefree, like a giant spotted apparition sliding out of sight into the deep blue.
Great white sharks are capricious fish. They are iconic, impressive, photogenic, and awe-inspiring but also frustrating. That frustration is not all about the animal — part of it is how few places in the world you can go to see them.
The Kingdom of Thailand, a sprawling Southeast Asian country slightly larger than California, shares land borders with four countries and neighbors a fifth by sea.
What is a safe carbon monoxide (CO) level in our breathing air? Learn the effects of CO poisoning and how the limits are derived.
There are many standards and guidelines for safe limits, including the results of various occupational health and safety studies on the effects of extended exposure. For diving, the situation is different. So what are safe limits for recreational diving with much shorter exposures than navy divers? Particularly, what is a safe limit for carbon dioxide (CO2), the most abundant potential contaminant?
