Deep in what might be called the Talmud of the Clean Air Act -- the official commentaries, rules and interpretations that have the force of law -- are several edicts that say, in effect: Thou shalt check air pollution at the neighborhood power plant for 24 hours before deciding if the emissions are excessive.

But in some states the time period is 30 days or longer, a crucial difference that can save a utility millions of dollars in pollution control equipment. The longer the interval for monitoring the air, the less likely that a single burp of emissions will send the entire pollution count over the federally mandated limit.

The Reagan admnistration wants to standardize that time period to an interval long enough to let more existing power plants work well within it.

It is just one of the dozens of regulatory mazes that the Reagan team plans to straighten out in its drive toward a new balance of environmental protection and energy needs.

The first major clash is likely to come over reauthorization of the Clean Air Act, which Republicans, including President Reagan, have criticized as overly restrictive on energy development projects.

But the process is heir to a decade of painful wrangling over details, and could be as complicated as rewriting part of the Talmud.

Major policies are hidden in small phrases, subordinate clauses and fine gray print in all existing environmental legislation and even more so in its regulations. Changes now in the works, set to begin in earnest after the regulatory freeze ends April 1, are not the splashy massive assaults on a problem that made high public drama of the original legislative wars.

Nor will these changes engage the attention of many Americans other than those who are paid to keep track of such things. Instead, they will be put forward in jargon and on a level of detail guaranteed to confuse non-experts.

"It's the kind of thing where a congressman is going to say to the staff guy, 'Just tell me how to vote,' and the third-level bureaucrat is the one who's going to get the pressure because the agency administrator will have to take his word for it," said a former Senate staff worker. Only the few who care very much will be involved in the decisions.

It is a new phase of the environmental wars, one in which all sides know intimately the major effect each tiny detail can have. The outcome of pending conflicts is likely to hinge on two still-amorphous disciplines: risk assessemnt, which tackles the question of how much safety or cleanliness are enough, and cost-benefit analysis, which tries to put dollar figures on human health and pleasure.

It is a far cry from the broad public anger over general air, land and water pollution of a decade ago that led to a lot of hastily written laws. Deadlines for regulations were set more or less arbitrarily to get the ball rolling.

"We set some of those standards in 90 days, so fast that nobody really knew what was happening," said David Hawkins, who was at the Natural Resources Defense Council prodding the rulemakers before he became President Carter's assistant administrator for air quality programs at the Environmental Protection Agency. "We were learning as we went along."

Repeated lawsuits from the Natural Resources Defense Council, the Environmental Defense Fund and other activist groups have been necessary to get any regulations out at all in some areas, especially in controlling toxic chemicals.

"That whole area was just far more complicated than anyone ever understood," said William Drayton, EPA's policy chief under Carter. Environmentalists accused the EPA of stalling and buckling to industry pressure, but harassed and overworked bureaucrats insisted that the level of detail required was at fault.

The same was true of air pollution from burning coal: rule-writers at first set blanket nationwide limits for the emissions. Slowly they learned that coal types vary practically from lump to lump and regulations have to take that into account. Meanwhile the rules infuriated a lot of coal industry experts who knew about the variations all along.

To a large degree the Reagan team is the beneficiary of a decade of such environmental education -- and the victim of this tradition of mutual suspicion and distrust. All sides hold the regulators highly suspect and are armed and girded for war.

Despite their criticism of the Clean Air Act, the Republicans are very much aware that people routinely tell pollsters they like clean air and water and won't stand for visible backsliding.

Sen. Robert Stafford (R-Vt.) has been on the rubber-chicken circuit making virtually the same speech since he became chairman of the Senate Environment Committee, which will handle the Clean Air Act debate.

"We can achieve the development of our domestic energy resources with full regard for our environment and health," he told the American Public Power Association in Washington recently. "The best way . . . is for all of us to work together in the spirit of cooperation, not confrontation."

That is echoed by Sen. James McClure (R-Idaho), chairman of the Senate Energy Committee, who told the same audience that what the law needs is "fine tuning, not major overhaul."

Still, environmentalists are very much aware that they are on the defensive, challenged to defend their successes of the past 10 years to a business-oriented administration. "We are in for a period of consolidation and deciding what's really bedrock important to us," said Rep. Morris K. Udall (D-Ariz.).