China and the US jockey for global influence in trade, economic development and technology innovation. But the US is happy to come in second in at least one metric: pollution.

When it comes to global carbon emissions, China is number one. And this week, President Barack Obama announced his plan to move the US further down that polluter list with a proposal to cut carbon emissions from existing power plants by up to 30 percent off 2005 levels.

But, it turns out, China's ready to compete on carbon, too. This week, a Chinese government advisor declared that China will limit total carbon emissions for the first time, with an absolute cap in place by 2016.

Jennifer Turner, director of the China Environment Forum at the Woodrow Wilson Center in Washington, DC, points out, though, that China's new cap is not set in stone. Still, she adds, it's a sign of things to come.

"It's a really strong indication that China is continuing to move in the direction of controlling emissions from coal," she says. "Coal is a major source of a lot of the smog that's been plaguing cities over the past decade, but increasingly worse over the past two years."

Within the past year, China created a pollution action plan that aims to cap coal use below 65 percent of total energy use, and introduce coal-free zones.

"Because the general public has been horrified, some cities are even going beyond what the government is requiring of them right now in terms of capping their consumption," Turner says. "It's a really positive trend, and in great part it's motivated for local health."

Turner says there are higher levels of asthma in China than the global average — and as many as 1.2 million people have died early from respiratory disease — because of air pollution. This is top of mind, now, because new technologies provide far greater transparency.

"Now, people can get live air quality updates," she says. "The government has set standards for particulate matter 2.5 and mandated that cities have to get this information out. At minimum, people can know when the air is really bad."

Nowadays, it's not just air quality that China is concerned about, even if coal is still the country's number one energy source.

"The Chinese government has led this clean energy revolution, and the industry has responded," Turner says. "They're number one in installed wind power, and they're ramping up solar PV. But at the same time, because their electricity consumption has, until recently, been accelerating so fast, coal still has dominated."

Turner adds that Chinese business leaders have begun to take the environment more seriously too. She says Jack Ma, the famous Chinese entrepreneur and founder of the Alibaba, one of Asia's largest online trading websites, has turned his sights to water quality.

"He's actually selling little water sampling kits so the public can sample water and upload their results online, and I think he's going to start moving into air as well," Turner says.