The Olympic Games have focused billions of eyes on Beijing, attracting attention to the athletes, the politics and - unavoidably - the pollution.
The country has taken drastic measures to try to clear the city's skies for the games, halting construction, factories and half of Beijing's cars.
But the smog is still there, and it has stirred up plenty of debate. Ethiopian runner Haile Gebrselassie, the world record holder for the marathon, in March pulled out of the event because of concern about how the pollution would affect his asthma.
The World Health Organization last year found China's air pollution to be the deadliest in the world, triggering diseases that kill 656,000 Chinese residents each year.
In an e-mail titled, "China's Olympic-Sized Growth in Emissions," the WorldWatch Institute last week released a report concluding that China made up a "staggering" 57 percent of the growth of carbon emissions from fossil-fuel combustion from 2000 to 2007.
According to the report, fossil-fuel-related carbon emissions grew 22 percent to an estimated 8.2 billion tons in the seven-year period.
All the attention on China's pollution has been good news for greentech.
China invested $12 billion in renewable energy last year and is expected to invest $175 billion in protecting the environment in the next five, according to the U.S. Department of Commerce (via CNBC).
Earth2Tech listed Cree, Suntech Power, Canadian Solar, ET Solar, Atos Origin, Echelon, Volkswagen, Feng Xingfu, Alcoa and General Electric Co. among the companies to benefit directly from selling greentech for the Olympics (also see ET Solar to Light Olympic Court).
Still, it's unclear how much of an impact the games really are having on the greentech industry in China.
Ira Ehrenpreis, a partner with venture-capital firm Technology Partners, said the Olympics are the latest event to underscore the need for clean technologies.
"The Beijing Olympics - with the heightened scrutiny on issues such as air quality in particular and energy demands in general - represent yet another example being played out on the worldwide stage that the need for greentech is here to stay," he said.
After all, Ehrenpreis said, the industry already is seeing unprecedented momentum from increased public awareness of environmental issues, a growing corporate focus on green and more political will to protect the environment, as well as examples of companies making money by going green.
And China was already well aware of its environmental issues and energy needs, he said. "The Chinese understand what they live with every day; they don't need the Beijing Olympics to explain their energy needs," he said.
The Olympics might be helping raise public awareness of China's environmental issues in the rest of the world, he said.
"When you see that, even with all the efforts China has made, athletes are unable to compete because of the air quality, and you look at the energy demands needed in the country because they are underscored by the Olympics, you see the real substantive drivers behind the need for clean technologies," he said.
Ron Pernick, a principal at research firm Clean Edge, said that when he was in Beijing two years ago, China already was poised to lead a number of clean-technology markets.
The country has a robustsolarwater-heating market and is ramping up wind-power manufacturing and deployment, as well as solar electricity, he said, adding that China would have been well positioned for greentech manufacturing regardless of the Olympics.
Still, Beijing clearly didn't hit the mark in terms of clearing up its air pollution on time, he said.
"I do believe there's a lot of great national pride around the Olympics, but in the end when you evaluate it, you have to see that they didn't make the goals," he said.
But he wouldn't discount the potential of big events to make a change.
"Long term, there's no doubt that the Olympics had an impact," he said. "Even though China has a central government with strong controls, I think it's partly going to take an uprising of the populace to make this happen. And the inability of the government to reach its goals, with all the effort it put toward this, really shows the magnitude of the problem and may then invigorate more significant investment and solutions."
Meantime, Matt Horton, a principal at venture-capital firm @Ventures, said he's seen some near-term changes in China's interest to showcase green technologies around the Olympics.
"My guess is the most lasting impact is China's desire not to be seen as a dirty, polluting old-energy kind of country, and I think allowing the world to come and see what things are really like on the ground there will hopefully motivate Chinese leadership to clean up their image," he said.
Now, when people think about China, many of them will think about the amount of pollution that China is producing, he said.
"Maybe China will feel a little bit more pressure to clean up," he said.
Like Ehrenpreis and Pernick, Horton added that plenty of un-Olympics-related drivers are pushing China to be a major manufacturer of green technologies as well.
"The Chinese government probably is somewhat disappointed that the very short-term measures it tried to put into place to clean the air for a couple of weeks didn't work, but it just reinforced the fact that it's not easy to fix this problem," he said. "It requires long-term action and significant investment to make it happen."