As people are allowed back into their homes in Sonoma, Napa and Mendocino counties, there are several safety issues to remember.

•Do not touch debris. Ash is a hazardous waste. Other hazards could include asbestos, heavy metals, byproducts of plastic combustion and other chemicals. Do not transport ash or debris to landfills or transfer stations. To be eligible for state-funded debris cleanup by CalRecycle, residents cannot move or spread debris. Any action by residents to remove debris may force CalRecycle to declare a site ineligible for the program.

•Wear protective clothing: closed-toed shoes, long pants, eye protection, a face mask and gloves.

•Do not rely on dust masks for protection. Paper masks found at hardware stores are designed to trap large particles like sawdust and will not protect your lungs from the smaller particles found in wildfire smoke. If you want to wear a mask, look for one with a particulate respirator, labeled NIOSH-approved, marked N95 or P100. Look for them on Amazon, Home Depot or other hardware retailers.

•Keep indoor air as clean as possible. Keep windows and doors closed.

•Avoid activities that increase indoor pollution like smoking, burning candles or using fireplaces. Vacuuming stirs up particles inside your house, contributing to indoor pollution.

•Do not turn PG&E service on. Either PG&E has been there and turned the gas on or homeowners must wait for them to do so. Customers without gas service should stay as close to home as possible so service can be restored when a PG&E representative arrives. If no one is at home, the representative will leave a notice with a number that customers can call to schedule a return visit. PG&E can be reached at 800-743-5000.

•If you see downed power lines near your home, treat them as if they are “live” or energized and extremely dangerous. Keep yourself and others away from them. Call 911, then notify PG&E at 800-743-5002.

A respite of rain expected to move into the area Thursday night will be a change for firefighters after a week of devastating fires across the North Bay.

The low-pressure system from the Gulf of Alaska is earlier in the year than expected, said forecaster Steve Anderson of the National Weather Service, and it brings a 70 percent chance of up to 0.3 inches of rain in the North Bay’s hills as soon as Thursday night, with between 0.1 and 0.2 inches falling in Santa Rosa.

While that might seem good for firefighting, a Cal Fire official said Monday that’s not necessarily the case.

“That’s not always preferred for us,” said Steve Crawford, who’s heading firefighting operations for the county’s three fires.

The current forecast of just a few tenths of an inch of rain could change repeatedly between now and Thursday afternoon when it’s due. If it remains on the lighter end and is accompanied by wind, it could make the situation worse, Crawford said.

“It’s not necessarily good news,” Crawford said. “We hope we get a half-inch of rain.”

The system will linger through Friday morning, according to the weather service, and shift the winds, clearing the air for smoke-weary North Bay residents who have been dealing with record pollutant levels.

The air, rated “unhealthy” Monday by the Environmental Protection Agency’s Air Now website, was set to improve Tuesday with a forecast rating of “unhealthy for sensitive groups.”

Also with the incoming system, temperatures are expected to dip and humidity rise.

Monday’s high of 88 degrees was predicted to be the hottest of the week, with temperatures falling into the 70s Thursday and Friday. Humidity, in the low teens Monday, will be in the 20 percent to 30 percent range.

Sunday, a high-pressure system is expected to bring temperatures in the 80s, and a chance of increased winds.

“We possibly could have some more wind concerns,” Anderson said. “It is certainly not enough rain to lessen the fire danger, so it’s something we’ll have to keep an eye on.”

Staff Writer Randi Rossmann contributed reporting. You can reach Staff Writer Christi Warren at 707-521-5205 or christi.warren@pressdemocrat.com. On Twitter @SeaWarren.