After five straight days of smoky conditions, the air quality got downright scary Friday, prompting a valley air district official to advise people to cancel outdoor activities.
In Stanislaus and Merced counties, the smoke from hundreds of Northern California wildfires pushed the air quality to the "very unhealthy" range.
It's believed to be the first time the air quality entered the so-called purple zone in the north part of the San Joaquin Valley.
"Any outdoor events at this level of unhealthy air should be canceled," said Anthony Presto, a spokesman for the eight-county San Joaquin Valley Air Pollution Control District. "At this stage, very unhealthy means simply that. It is very unhealthy to breathe the air outside right now. The best thing is for people to remain indoors where you can use a filtered air conditioner."
The very unhealthy conditions are forecast for today as well and valley residents can expect the smoke to linger for several days.
According to district guidelines, young children and seniors, as well as people with chronic health conditions, should avoid all physical activity outdoors today. Everyone else, especially children, should avoid prolonged or heavy exertion outdoors.
The bad air can damage the lungs of children, trigger asthma attacks, or result in heart attacks and arrhythmia in people with heart problems, health experts say.
Organizations appeared to be getting the message.
The YMCA of Stanislaus County canceled final baseball games for children today, moving award ceremonies to its McHenry Avenue building in Modesto.
Chief Executive Officer Phil McGovern said the YMCA will have to decide about day camps next week.
The Youth Action Commission of Stanislaus County had planned a "Let's Get Moving" walk-a-thon today to promote healthy living. But organizers put that on hold until late July or August.
The group still plans to hold its graduation ceremonies at 5 p.m. today at the Modesto Police Department.
Worsened by weather system
Officials said the air quality deteriorated further because of a ridge of high pressure moving over California from the Southwest. It strengthened the natural inversion layer that traps pollutants over the San Joaquin Valley, pushing the sooty particles and other pollutants closer to the ground.
Of concern are the tiny particles that can get deep into the lungs. The concentration of those particles got close to the very unhealthy range Friday in Modesto.
Ozone is the main pollutant driving the "very unhealthy" reading in Stanislaus County, especially high ozone readings in Turlock, said Shawn Ferreria, a senior air quality specialist for the valley air district.
The air in San Joaquin County was rated unhealthy Friday and will be unhealthy today, the district said.
It uses an air quality index calculated from five common pollutants to rate the air quality on a six-point scale: good, moderate, unhealthy for sensitive groups, unhealthy, very unhealthy and hazardous.
It's rare for the pollution to reach the very unhealthy level, but it has happened this week in Kern, Tulare, Fresno and now Stanislaus and Merced counties.
Ferreria said the conditions in the San Joaquin Valley are not as dire as in the foothills, which have approached the hazardous rating.
Stanislaus County health officials said they have not seen any advisories on the bad air from the state Department of Public Health. At some point, county emergency services agencies could discuss further measures for protecting the public. We anticipate that, if this carries over the weekend, that will be quite a few sequential days and perhaps we will start talking," said Dr. Janwyn Funamura, assistant public health officer for Stanislaus County.
Beside staying indoors, people can do other things such as keeping the windows up while driving and pressing the recirculation button on their car air conditioners.
Many home air-conditioning units have air intake filters that keep clean air circulating inside the home. People can avoid adding to indoor air pollution by not smoking, not burning candles and not using vacuum cleaners, which can stir up dust, Funamura said.
People working outdoors, particularly in areas near fire activity, may want to wear disposable particulate respirators, as the California Air Resources Board and local air districts suggest.
The recommended types of respirators can be found at hardware stores. They have two straps and are designated "N-95" or "P-100," the California Division of Occupational Safety and Health said. The respirators offer limited protection, because they do not provide oxygen or filter many of the toxins in smoke.
The air district is discouraging valley residents from celebrating with home fireworks during the Fourth of July.
Gov. Schwarzenegger said Friday he would not order a statewide ban of fireworks. But because of fire danger, he said, "I do encourage fire-affected counties to take a good look at their resources and take the appropriate steps at the local level, including a fireworks ban if necessary to protect their communities."
Information about indoor air pollution and filter devices is available at
In Stanislaus and Merced counties, the smoke from hundreds of Northern California wildfires pushed the air quality to the "very unhealthy" range.
It's believed to be the first time the air quality entered the so-called purple zone in the north part of the San Joaquin Valley.
"Any outdoor events at this level of unhealthy air should be canceled," said Anthony Presto, a spokesman for the eight-county San Joaquin Valley Air Pollution Control District. "At this stage, very unhealthy means simply that. It is very unhealthy to breathe the air outside right now. The best thing is for people to remain indoors where you can use a filtered air conditioner."
The very unhealthy conditions are forecast for today as well and valley residents can expect the smoke to linger for several days.
According to district guidelines, young children and seniors, as well as people with chronic health conditions, should avoid all physical activity outdoors today. Everyone else, especially children, should avoid prolonged or heavy exertion outdoors.
The bad air can damage the lungs of children, trigger asthma attacks, or result in heart attacks and arrhythmia in people with heart problems, health experts say.
Organizations appeared to be getting the message.
The YMCA of Stanislaus County canceled final baseball games for children today, moving award ceremonies to its McHenry Avenue building in Modesto.
Chief Executive Officer Phil McGovern said the YMCA will have to decide about day camps next week.
The Youth Action Commission of Stanislaus County had planned a "Let's Get Moving" walk-a-thon today to promote healthy living. But organizers put that on hold until late July or August.
The group still plans to hold its graduation ceremonies at 5 p.m. today at the Modesto Police Department.
Worsened by weather system
Officials said the air quality deteriorated further because of a ridge of high pressure moving over California from the Southwest. It strengthened the natural inversion layer that traps pollutants over the San Joaquin Valley, pushing the sooty particles and other pollutants closer to the ground.
Of concern are the tiny particles that can get deep into the lungs. The concentration of those particles got close to the very unhealthy range Friday in Modesto.
Ozone is the main pollutant driving the "very unhealthy" reading in Stanislaus County, especially high ozone readings in Turlock, said Shawn Ferreria, a senior air quality specialist for the valley air district.
The air in San Joaquin County was rated unhealthy Friday and will be unhealthy today, the district said.
It uses an air quality index calculated from five common pollutants to rate the air quality on a six-point scale: good, moderate, unhealthy for sensitive groups, unhealthy, very unhealthy and hazardous.
It's rare for the pollution to reach the very unhealthy level, but it has happened this week in Kern, Tulare, Fresno and now Stanislaus and Merced counties.
Ferreria said the conditions in the San Joaquin Valley are not as dire as in the foothills, which have approached the hazardous rating.
Stanislaus County health officials said they have not seen any advisories on the bad air from the state Department of Public Health. At some point, county emergency services agencies could discuss further measures for protecting the public. We anticipate that, if this carries over the weekend, that will be quite a few sequential days and perhaps we will start talking," said Dr. Janwyn Funamura, assistant public health officer for Stanislaus County.
Beside staying indoors, people can do other things such as keeping the windows up while driving and pressing the recirculation button on their car air conditioners.
Many home air-conditioning units have air intake filters that keep clean air circulating inside the home. People can avoid adding to indoor air pollution by not smoking, not burning candles and not using vacuum cleaners, which can stir up dust, Funamura said.
People working outdoors, particularly in areas near fire activity, may want to wear disposable particulate respirators, as the California Air Resources Board and local air districts suggest.
The recommended types of respirators can be found at hardware stores. They have two straps and are designated "N-95" or "P-100," the California Division of Occupational Safety and Health said. The respirators offer limited protection, because they do not provide oxygen or filter many of the toxins in smoke.
The air district is discouraging valley residents from celebrating with home fireworks during the Fourth of July.
Gov. Schwarzenegger said Friday he would not order a statewide ban of fireworks. But because of fire danger, he said, "I do encourage fire-affected counties to take a good look at their resources and take the appropriate steps at the local level, including a fireworks ban if necessary to protect their communities."
Information about indoor air pollution and filter devices is available at
