TAIYUAN, CHINA — Su Aimin spat on the ground, and admired the result.
"You see, it's white," said the 33-year-old production manager at Taiyuan Iron & Steel, pointing to his saliva. "Before, it was black. I'm not kidding."
Although Beijing is still struggling to make the skies clear for the Olympics, a massive cleanup effort before the Summer Games has given people here a taste of fresh air. They want to keep it that way, but business groups are likely to lobby for an easing of the restrictions.
Even Taiyuan residents acknowledge that improving the environment might come at the cost of some jobs and economic development.
Taiyuan, an industrial city 250 miles southwest of Beijing, has long been considered one of the most polluted in the world. But in recent months, authorities have closed dozens of coal mines and coking operations. In addition, production at steel mills, cement factories and power plants has been cut back or suspended, as it has in several other provinces, to reduce the pollution blowing into Beijing during the Olympics.
"The air now is the best in at least 10 years," said Jin Gongyuan, a professor at Shanxi University of Finance and Economics in Taiyuan.
But the big question for Jin and others in this provincial capital of 3 million is: What will happen after the Olympics?
"Could it be possible that such measures would last longer or even be permanent?" Jin asked. "Not only do foreign athletes need fresher air, we need that too."
Chinese environmental activists hope that the Olympics will usher in an era in which pollution control regulations are taken seriously by government and industry. But many wonder whether strict enforcement can be sustained, especially in areas far from Beijing.
Clear, blue skies are rare in many Chinese cities, which have some of the dirtiest water and filthiest air in the world. In recent years, the government has sought to reorient economic growth in a way that would spare degradation to the environment, but those efforts have been undermined in many places by corruption and an intense focus on development and moneymaking.
The pre-Olympics clean air measures have affected hundreds of factories, from northern China's coastal area up to the edge of the Gobi Desert in Inner Mongolia. For the most part, the shutdowns or cuts in output are slated to last until the end of the Paralympics in September.
Few details of the restrictions have been released. But China is likely to keep its anti-pollution campaign in force after the Olympics, a senior official at the Ministry of Environmental Protection said Sunday, according to the official New China News Agency.
"Most of these measures are long-term ones and will remain after the Games. Not all the temporary measures will be retained after the Games, but they may provide clues for our future work," said Fan Yuansheng, head of the ministry's pollution-control department.
Business groups are expected to argue that China's economy is slowing from the global weakness and that persistent pressure to make environmental upgrades to facilities will result in more job losses. Even people in Taiyuan who are happy to be breathing cleaner air express concern about the economic effects of the tougher environmental regulations.
"For sure, the air is better than before," said Yang Yingxi, 48, a restaurant owner in the Wanbolin district. But he quickly added that with the closing of coal mines, his business had evaporated in recent months.
"Is there a way we can have both?" he asked, standing forlornly behind the counter of his nearly empty diner.
China has spent $16 billion to improve the air for the Games. In Beijing, officials say they have issued more than $400,000 in fines to construction companies this year for producing excessive levels of dust.
Beijing also has ordered 1.5 million cars off the streets, mandated emissions standards for all coal-burning boilers in the city and stepped up inspections of gas stations, printing shops, furniture makers, dry cleaners and other industries that may be discharging sulfur oxides, nitrogen oxides or other pollutants.
"Beijing has made a lot of effort, but these are temporary measures," said Ma Jun, director of the Institute of Public and Environmental Affairs, a nongovernmental organization in Beijing. "This time, the Olympics have helped to identify the problems and the source of the bad polluters. Now I think we shouldn't let that go.
"We're talking about the quality of life and the health of tens of millions of people. It's more important than the Games," he said.
Here in Shanxi province, China's coal country, officials have been keen on shutting down substandard mining operations for environmental and safety reasons. The industry has been plagued by accidents that cost thousands of lives annually.