You may have read some alarming stories recently about pollution making its way from China to the U.S. Should you worry?

In fact, a cloud of soot, sulfur dioxide and sand from China’s Gobi Desert does make it to cities of the western U.S., where it accounts for, by some measures, as much as 15 percent of local air pollution. Of course, air pollution that doesn't respect international boundaries is nothing new: the rain acidifying the lakes of eastern Canada comes from the U.S., for example.

But China is doing something about the problem, thanks to very real impacts on public health and even children's development, as we note in our recent in-depth report on China and the environment. Whether it's having one of only four cities worldwide to go carbon neutral, cleaning up indoor air by burning human waste, or pushing renewable energy, the Middle Kingdom has a host of efforts underway. Of course, there's still a growing love of cars to deal with as well.

The National Academies of Science is currently digging into the question of what impact all this pollution will have on the U.S. But one thing is clear: as much as one-third of China's pollution comes from making goods for the U.S. market. You can outsource manufacturing to developing countries with more lax environmental standards, but the pollution will still come back to you. There's only one atmosphere after all.