"From the suggestions of experts we think that we need to take these measures to guarantee the air quality of Beijing," said Du Shaozhong, the bureau's deputy director.
The measures are severe and will be in effect officially for two months - July 20-Sept. 20 - although reports a few months ago suggest some production cutbacks may come even sooner.
Officials also are expected to ban about half of Beijing's 3.3 million vehicles for the Aug. 8-24 Olympics. Du said specific details would be announced later.
A month ago, pollution looked like the biggest threat to the Olympics, which are supposed to mark the emergence of China as an economic and political power. Since then, deadly riots in Lhasa have triggered worldwide demonstrations by pro-Tibet and human rights groups, threatening the country's image on a stage it has spent billions to build.
Last week, chaotic protests disrupted legs of the Olympic torch relay in London, Paris and San Francisco, prompting usually cautions International Olympic Committee President Jacques Rogge to say the IOC was facing "a crisis" - one of its toughest tests since the boycotts of the 1970s and '80s.
More demonstrations along the relay route are expected.
Beijing's noxious pollution still presents an enormous problem, a health menace and a public relations minefield.
Rogge has said endurance events of more than an hour will be postponed if the air quality is poor, and he's acknowledged some performances might be "slightly reduced." Many top athletes are reported staying away from the games until the last minute, and some have been advised to wear masks in non-competition situations.
Du did not say if shuttered companies would receive compensation for lost production.
"Enterprises have made active sacrifices for the Olympics in terms of how to allocate their production and how to offset all these negative impacts," he said.
To a suggestion that some companies might ignore the government orders, Du replied: "It's not very difficult for Chinese plants to implement all the measures."
The Capital Steel Group in west Beijing has been told to reduce emissions, and production will be halted at the Eastern Chemical Plant of Beijing Eastern Petrochemical Co. In addition, coal-burning boilers that fail to meet emission standards also will be shuttered.
Du said production would be stopped at concrete and cement plants in southeastern Beijing. Quarry operations will also be stopped.
The environmental body said gas stations, oil depots and tanker trucks would be shut down unless they were equipped with "oil vapor recovery" technology.
Outdoor spray-painting will also be banned during the period, and "spraying or painting with harmful solvents will be temporarily banned."
Du said even more "strident" measures would be taken during the 17-day games "in case of extremely negative meteorological conditions." Hot, humid and stagnant air often settles over the city in August.
Five provinces and municipalities surrounding Beijing will also be closing factories, although their plans were not released. They are: the city of Tianjin; Hebei, Shanxi and Shandong provinces; and the huge Inner Mongolia region.
Beijing is one of the world's most polluted cities. A mix of particulate matter, carbon monoxide, sulfur dioxide and nitrogen dioxide often blankets the city at levels five times higher than World Health Organizations safety standards.
As Du made his announcement, Beijing was covered in a moderate level of smog.
An IOC study released last month said that competition conditions would "not necessarily (be) ideal at every moment," but said Beijing's air quality was better than expected.
Asked if he could make a 100 percent promise that no endurance events will be postponed by pollution, Du replied: "We will do everything possible to honor the promise."