Blaze Brings Calls to Remain Indoors

Dense smoke from flames charring the Ventura County backcountry prompted officials to expand health advisories to restrict athletic events and other outdoor activities as smoke blew into towns and threatened human health.

The raging wildfire, now in its third week, has cut across 97,685 acres in the Los Padres National Forest, spreading smoke far across Ventura County and northern Los Angeles County.

“This sucker has been erratic,” said Dee Dechert, a U.S. Forest Service spokeswoman. “It does what it wants to do.”

Fickle winds spread the smoke and ash plume into more communities this week, exposing more people to harmful pollutants. Regional air quality officials issued smoke and health advisories for the Santa Clarita Valley, northern San Gabriel Mountains and most of Ventura County.

Air quality officials warn everyone, especially senior citizens, small children, active athletes and people with respiratory conditions, to remain indoors or sharply restrict outdoor activities in those areas.

“If you see smoke or smell smoke where you’re at, it’s time to curtail activities,” said Mike Villegas, executive officer for the Ventura County Air Pollution Control District.

Ojai has felt the brunt of the smoke. Concentrations of tiny smoke particles reached 173 micrograms per cubic meter for one hour on Sunday, more than eight times the recommended limit, air quality officials reported, and poor conditions prevailed during much of Tuesday.

“Monday it was really thick and ugly, so we canceled all P.E. classes and all sports,” said Dan Musick, principal at Nordhoff High School in Ojai. “We didn’t want any strenuous conditioning, kept it low-key, no one worked up a big sweat.”

Smoke is a complex mixture of easily inhaled particles and gases produced by high temperatures in wildfires.

About 90% of the pollutants in smoke are microscopic particles, including tar, soot and assorted chemicals. Smoke can cause respiratory illness, shortness of breath and trigger asthma attacks.

Carbon monoxide and nitrogen oxides, the same substances released by vehicle tailpipes, are also produced by wildfires, especially near the flames.

Carbon monoxide robs the body of oxygen and can cause headaches, dizziness and asphyxiation.

Other substances are present as well, including formaldehyde, acids and a class of cancer-causing compounds called polycyclic aromatic hydrocarbons.

“The fine particles can lodge deep in the lungs and exacerbate respiratory problems. That’s why the elderly and children are especially susceptible and need to take greater precautions,” said Tina Cherry, spokeswoman for the South Coast Air Quality Management District.

The Day fire, so called because it began on Labor Day, has burned largely unchecked as crews struggle in mountainous terrain to expand containment beyond 20%, according to the U.S. Forest Service. The blaze was concentrated in Lockwood and Rose valleys, about seven miles north of Fillmore on Wednesday. About 2,100 firefighters are engaged, and no lives or structures have been lost.

gary.polakovic@latimes.com