Take a deep breath. Chances are, the air filling your lungs is far from pure. Even if you live in a clean, ecologically conscious area, you may be inhaling pollutants from faraway, less-pristine locales. Your hometown air may contain microscopic particles of mercury-coated coal dust from China, diesel from Europe, ozone from Los Angeles, or carbon monoxide from India—or possibly a cocktail of all of the above.
With more and more travelers looking to take a breather from pollution, it’s no surprise that destinations are starting to boast about having the world’s cleanest air; Tasmania, Hawaii, and Antarctica have all staked their claim. But even in the wilds of Alaska it’s possible to suck in trace elements of toxic fumes from Siberian coal mines. So where, exactly, can travelers go to be sure of finding pure O2?
Answering that question, it turns out, is far from easy. There’s no worldwide clearinghouse for this information, and even defining the term “clean air” can be challenging.
Air cleanliness is usually measured by monitoring stations set up by local governments with the purpose of assessing long-term changes in carbon dioxide or ozone. These stations track air purity by measuring more than 250 pollutants, which can vary drastically in their harmfulness. “The whole picture is so complex,” says Russell Schnell, a deputy director at the National Oceanic and Atmospheric Administration, explaining that pollutants come in many forms. Air that looks clean can still harbor invisible, odorless toxins, while a hazy horizon can sometimes be caused by harmless water vapor.
Another variable is where these stations are set up. Put one in the center of Honolulu and it will give different results than one on top of 11,000-foot Mauna Loa, where Hawaii’s station is. Up there, the air’s virtually free of pollution, so it’s no surprise that the Big Island makes an appearance on our list.
To further complicate matters, pollution levels can change seasonally. Light, cold, and rain can change the air’s composition. “One of the cleanest places on earth is probably in the South Pacific—but only during the wet season,” says Mark Jacobson, professor of civil and environmental engineering at Stanford University. During that time of year, he says, rain can wash away pollutants.
In other words, data alone couldn’t help us find the world’s cleanest air—which is why we didn’t rank our list. We also turned to the experts; by collecting opinions from groups like NASA and the World Meteorological Organization, we were able to glean enough information to put together our list of worldwide easy-breathing spots.
There were a few surprises along the way. It came as quite a shock, for instance, that all of Continental Europe had to be excluded from our list. (The reason: population density combined with reliance on diesel engines.) Another surprise?Forest air doesn’t necessarily mean clean air. While destinations with abundant foliage do soak up carbon dioxide, trees and traffic can be a hazardous mix. “When you smell lemon, for example, you’re really smelling the hydrocarbon limonene, a gas emitted by lemons,” explains Jacobson. “When it combines with sunlight and oxides of nitrogen from cars, it produces the pollutant nitrogen. That’s one of the reasons there is so much pollution in some parks.”
Surely tropical islands are free from nasty particles?Not necessarily. The preponderance of older cars on many islands (Jacobson estimates that 1,000 old cars without emission controls produce as much pollution as 100,000 new cars), along with the fact that many of these idyllic places burn sugarcane, winds up causing a lot of pollution. As a result, much of the Caribbean and Equatorial Asia didn’t make the cut—though Tahiti did.
One area with an especially strong quotient of clean: the Southern Hemisphere. Up north, more land, cities, people, and cars mean that even the cleanest places are twice as dirty as remote southern locales. “The two hemispheres are pretty separated dynamically,” says Daniel Jacob, professor of atmospheric chemistry and environmental engineering at Harvard University. He explains that weather patterns (and therefore air molecules) circulate rapidly around the globe in an easterly direction, but are discouraged from moving to another hemisphere by the still air at the equator known as the doldrums. “The air in northern latitudes takes about a month to circle the globe, but it takes about a year to cross the equator,” he says.
So where can travelers go for a breath of fresh air?Some places, while undoubtedly pure, were too remote and lacking in tourism infrastructure to consider (our apologies to the Indian Ocean’s Kerguelen Island and its 70 year-round inhabitants). But here’s our list of more easily reachable destinations with super-clean air—and 10 ways to fill your lungs with it.