Cooley Fire Holds at 731 Acres as Smoke Triggers Bay Area Air Advisory for Sonoma, Marin, and Napa

Cooley Fire Holds at 731 Acres as Smoke Triggers Bay Area Air Advisory for Sonoma, Marin, and Napa

“Smoky, hazy skies may be visible, the smell of smoke is possible,” the district said. It did not call a Spare the Air alert, because it did not expect pollution to exceed the national 24-hour health standard. Short bursts of heavy smoke can still irritate the lungs, especially for children, older adults and people with respiratory illnesses.

For North Bay families, the practical problem is that smoke can shift quickly from block to block and hour to hour. A clear morning can turn hazy by afternoon, so checking a live air reading before a run, a soccer practice or a long walk with a stroller is more reliable than relying on a forecast. The fire started around 5:05 p.m.

on Oct. 16 near Elkhorn Road and Cooley Ranch Road in southern Mendocino County, close to the Sonoma County line, according to the Cal Fire incident page. It had burned 731 acres and was 5% contained as of Cal Fire’s Sunday morning update, reported by Mendo Voice.

Cal Fire lists the cause as under investigation and said additional firefighting resources had been ordered. Crews are working in steep, rugged terrain with limited access. The Press Democrat has reported the blaze as an escaped prescribed burn near Lake Sonoma.

Days earlier, the Mendocino County Air Quality Management District had announced planned burns on Cooley Ranch of up to 850 acres on Oct. 16 and up to 500 acres on Oct. 17, cautioning that smoke could temporarily affect local air quality.

Officials have not publicly explained how the burn moved beyond its planned area or whether the second day of burning went ahead. Those answers matter for public trust in prescribed fire, a tool land managers use to reduce fuel and lower the risk of larger wildfires. No evacuation orders were listed on the Cal Fire incident page as of its latest update.

Wildfire smoke is a mix of gases and tiny particles known as PM2.5, which are small enough to travel deep into the lungs. According to the AirNow wildfire smoke guide for public health officials, these particles can irritate the eyes, nose, and throat, cause coughing, trigger asthma attacks, and worsen chronic lung disease. The particles can also strain the heart.

The guide says smoke exposure has been linked to chest pain, abnormal heart rhythms and heart attacks in people with heart disease. Recent research has suggested that wildfire smoke may be linked to higher heart and lung hospitalization risk than the same levels of other air pollution. The air district says older adults, children, and people with respiratory illnesses should take extra precautions, and that smoke can trigger wheezing in people with asthma, emphysema, or COPD.

The AirNow guide also identifies pregnant people, people with heart disease, and outdoor workers as groups at higher risk. The smell of smoke is not a reliable measure of risk, because fine particles are invisible. They can remain in the air after the odor fades, and a strong smell does not always mean particle levels are high.

The district directs residents to the AirNow Fire and Smoke Map, which combines official monitors with low-cost sensor data and updates throughout the day. The district advises residents to stay indoors with windows and doors closed when smoke is present, if temperatures allow, and says exposure to smoke is unhealthy even for short periods. Drivers should set car ventilation to recirculate.

People without good indoor filtration can go to a Clean Air Center or another filtered-air location, such as a library or shopping mall. At home, a portable air cleaner with a high-efficiency filter can lower indoor particle levels, particularly in a bedroom where family members sleep. Central air systems can help if the filter is rated MERV 13 or higher, according to the AirNow guide.

Avoid frying, burning candles, and vacuuming without a HEPA filter on smoky days, since these add particles indoors. Outdoors, a well-fitted N95 respirator offers some protection, while cloth and surgical masks offer little or none against fine particles. N95s are not made to fit children and may be hard for people with lung or heart conditions to wear, so those families should focus on staying indoors with cleaner air.

Parents can check readings before school pickup or outdoor practice and move activities indoors when the map shows unhealthy levels. People with asthma should keep rescue inhalers on hand and follow their action plans. Seek medical advice for a persistent cough, wheezing, or worsening asthma.

Chest pain, severe shortness of breath, confusion or fainting require emergency care. Smoke patterns depend on wind direction, fire activity and containment progress, all of which can change quickly. The district said residents should follow instructions from local health officials and use the Fire and Smoke Map to check conditions where they live.

Key questions remain. Investigators have not confirmed how the fire started, and it is unclear how long smoke will affect Sonoma, Marin, and Napa. Until conditions clear, the most useful habit for North Bay residents is simple: check live readings before heading outside, and keep indoor air as clean as possible.

Which areas were affected by Cooley Fire smoke? Smoke affected Sonoma County and was expected to move into parts of Marin and Napa counties, according to the Bay Area Air District. No.

The district said pollution was not expected to exceed the national 24-hour health standard, though air could be unhealthy at times. Cal Fire reported 731 acres and 5% containment as of its Oct. 18 morning update.

The cause is under investigation. Children, older adults, and people with asthma, COPD, or other lung conditions. Pregnant people, people with heart disease, and outdoor workers also face higher risk.

How can I check air quality where I live? Use the AirNow Fire and Smoke Map at fire.airnow.gov, which updates throughout the day. Chest pain, severe shortness of breath, confusion, or fainting require emergency care.

A persistent cough or worsening asthma should prompt a call to a clinician.