Fires

Here's the air quality outlook for July 4 and beyond, amid Northern California wildfires

Sacramentans planning to watch fireworks burst in the area on Wednesday might not have to worry too much about air quality, but conditions may worsen as the week wears on.

On Tuesday, Sacramento is forecast to experience similar weather conditions as it did Monday, said Thomas Hall, spokesperson for the Sacramento Metropolitan Air Quality District. That means a clearer morning, followed by the potential for smoke in the evening.

For the Fourth of July, onshore winds (aka the Delta Breeze, which blows from south-southwest to north-northeast) are predicted to dominate in the region. As the County Fire is currently burning northwest of Sacramento County, these winds shouldn't dramatically worsen smoke conditions Wednesday, Hall said.

Thursday will potentially be the worst day this week for smoke in the county, as winds are expected to turn instead toward the southeast, Hall said.

On Monday, Elk Grove and the Arden Arcade area faced the highest particulate matter (PM) concentrations, but it's unclear whether or not that pattern will continue Tuesday night, Hall said.

All of this could change, Hall cautioned, if more wildfires ignite throughout the week. As long as smoke remains in the air, ozone levels are expected to increase, but they are not forecast to exceed the range typical for this time of year. Although normal, these ozone levels are considered unsafe for at-risk groups, such as children, older adults and those with lung conditions.

Smoke will continue to inundate cities near the blaze on Tuesday, according to the Yolo-Solano Air Quality Management District. The cities of Vacaville and Dixon will experience the worst smoke in the morning and afternoon, while Esparto, Davis and Woodland will be affected in the late afternoon and evening.

On Wednesday, the Delta Breeze will carry most of the smoke toward those three cities, Yolo-Solano Air Quality Management District spokeswoman Jenny Tan said.

Still, Tan said, the winds have been particularly unpredictable as of late, so residents in Rio Vista and Knights Landing should be prepared to take the necessary precautions if they smell smoke coming their way.

Smoke is not expected to completely clear up in Yolo and Solano counties before the end of the week, Tan said.

In general, residents should avoid outdoor physical activity, close windows and doors that might let in smoke, turn off all wood-burning appliances and turn on their air conditioners, according to the district.

Anyone who feels nauseous, dizzy or otherwise unwell after exposure to smoke is encouraged to contact their doctor, Tan said.

Much of the Bay Area received a respite from smoke on Tuesday. According to the Bay Area Air Quality Management District, an inversion layer was protecting San Francisco and the surrounding regions from incoming smoke as of 10:30 a.m. The predicted wind change will also draw smoke away from the region Wednesday and the rest of the week, the district said.

Hourly updates on PM concentration across the state are available via Wildland Fire Air Quality Response Program's monitoring service.

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The predicted wind direction and its effect on the County Fire for July 3 & 4. Bay Area Air Quality Management District

Many regional air quality management districts in Northern California are cautioning residents about the added health hazards that fireworks pose.

Fireworks release nefarious particles such as soot, ash and metals into the atmosphere, and air monitors in the San Joaquin Valley have accordingly detected unsafe spikes in PM concentrations every July 4 evening, the district said.

As such, the city of Winters in Yolo County had canceled its July 3 fireworks show as of Monday morning.

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On July 4, 2017, in the city of Visalia, particulate matter levels in the air exceeded the "Heavily Polluted" benchmark around 10 p.m., rendering the air unsafe. San Joaquin Valley Air Pollution Control District


If outdoors in hazardous conditions, residents should consider donning face masks with high efficiency particulate air (HEPA) filters or an N-95 mask, as regular dust masks don't filter out wildfire air pollution safely, the American Lung Association advises. These warnings are especially pertinent for members of at-risk groups.

In general, smoke may look entirely gaseous, but it contains miniscule chunks of PM that pose health risks ranging from headaches to heart problems.

Combined with cloudless weather and hot temperatures, smoke concentration increases the production of ozone. The molecule is an essential component of the Earth's upper atmosphere, but it's unhealthy and synonymous with smog when present in altitudes closer to sea level.

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