Environmental Protection Agency officials have drafted a proposal that would weaken air quality standards limiting the amount of soot and microscopic chemical particles in the air, according to agency employes.

The draft proposal was criticized yesterday at a news conference called by the Natural Resources Defense Council and seven other environmental groups. NRDC attorney David Doniger said the EPA's figures show that the changes being considered in the way particulates are measured and defined would permit a 41 percent annual increase in soot and tiny particles in the air.

The draft was written after an EPA scientific advisory panel suggested that the agency focus its attention on particles small enough to enter a human lung. Current standards do little to differentiate between large particles that soil clothes and buildings and smaller particles. The new draft pays more attention to smaller particles, but permits greater overall pollution of the air.

Agency staffers said that earlier this year EPA Administrator Anne M. Burford pushed hard to get the draft proposal out quickly. But that was before the current storm of criticism hit the agency. Agency officials said yesterday that required review procedures would keep the draft from reaching Burford's desk before April.

Doniger charged yesterday that, if the draft rule goes into effect, the lag time between amending the standard and obtaining 5,000 new monitoring devices would leave most areas without a workable standard for months or years.

The American Mining Congress has sent the EPA a study developed by two Johns Hopkins researchers indicating that particles larger than 10 micrograms are unlikely to enter the human lung, a conclusion that would support a greater relaxation of particulate standards than the EPA draft proposes.