Northern California’s raging wildfires have blotted the skies with acrid smoke for weeks, but the air quality has still been better than a bad winter day.
More than half a dozen test sites throughout the Sacramento Valley routinely registered higher measurements of the potentially harmful substance known as PM2.5 during the month of January, according to Sacramento Bee analysis of data from California Air Resources Board.
The highest recording during the last 10 years in Sacramento County was 74 micrograms per cubic meter recorded in June 2008 when there was an active fire in the county, the data show. The second-highest reading — 64 micrograms per cubic meters — was registered on T Street in February of this year.
The culprit: wood-burning stoves and fireplaces.
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Like the wildfires that are scorching communities this summer, they each release particle pollution into the atmosphere, creating possibly dangerous health issues for some.
Public health groups and environmental advocates say the trend should concern residents all year and not just when there’s a wildfire.
“These fine particles get into our lungs, get into our bloodstream and damage our health so whether it’s in the wintertime or the summertime,” said Bill Magavern, policy director for the Coalition for Clean Air.
“Whether it’s through burning of fossil fuels or through wildfires the levels of particulate matter that we’re seeing now and that we’ve seen in the past in the Sacramento area are a concern.”
Ozone, which is also tracked with particulate matter, tends to get a lot of the attention. It forms in hot, sunny conditions when, for example, the exhaust from vehicle tailpipes go into the atmosphere. That turns into the haze known as summertime smog.
But both ozone and particulate matter are pollutants that threaten public health, which is why many closely watch the Air Quality Index. But if you isolate the particle pollution, which has been linked to cancer, respiratory issues and low-birth weight, the higher levels during winter are undeniable.
“Particle pollution are tiny droplets and bits of ash and soot and diesel exhaust that form up and tend to show higher in the winter months when we see spikes in fireplace usage,” said Will Barrett, who advocates for clean air on behalf of the American Lung Association in Sacramento.
“That’s when we tend to see more of the wintertime impact from particle pollution when weather conditions are more likely to trap pollution for days on end if there’s a stagnant air period and not a lot of rain, we can see weeks on end of particle pollution trapped close to the ground and causing health impacts and fine particle pollution.”
The peak pollution levels aren’t always present at each collection site that covers the area between from Sacramento and Solano counties, north to Shasta County.
It’s more common in the cities of the four-county Sacramento region, including Woodland, Elk Grove, Roseville and most of the four testing sites in Sacramento. The city of Chico in Butte County also sees higher particle pollution levels in the winter.