Thanks to wildfires blanketing Central California, Merced County's air quality could remain bad for the second day in a row today.
Shawn R. Ferreria, Fresno-based senior air quality specialist with the San Joaquin Valley Air Pollution Control District, said Monday's air quality index registered 140 in Merced County and is predicted to stay at 129 today. Any reading between 101 and 150 is considered unhealthy for sensitive groups.
Ferreria said rising ozone readings were beating out measurements of particulate matter churned out by the spate of wildfires and both ozone and particulate readings are responsible for the unhealthy for sensitive groups rankings.
A spokesman for Mercy Medical Center Merced said Monday the hospital's emergency department has not encountered any significant increase in respiratory cases because of smoky air conditions in this area.
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Stanislaus County's air quality readings were 147 on Monday and predicted to be the same for today. The air district's closest live monitoring station to Merced is in downtown Turlock. It measures particulate matter 2.5 microns in size or smaller, one of the byproducts of wildland fires that are still burning in Mariposa County and other parts of the state.
Lightning strikes Saturday in the foothills triggered a number of dry vegetation fires in Merced and Mariposa counties. The impact of these fires was light Sunday but worsened Monday, with the smell of smoke evident and the sky murky.
Things were worse in San Joaquin County, Ferreria said. Monday's air quality reading there was 156 and expected to be 155 today. Air quality readings of 150 to 200 are considered unhealthy for all groups.
Ferreria said residents with asthma or other lung problems are urged to stay indoors. The small particles in the smoke are capable of getting deep into the lungs, causing health problems.
Exposure to the particle pollution can aggravate lung disease, cause asthma attacks and acute bronchitis and increase the risk of respiratory infections, according to the air district.
Short-term exposure to particle pollution has also been linked to heart attacks and arrhythmias in people with heart disease, according to the U.S. Environmental Protection Agency.
Older adults and children should avoid prolonged exposure, strenuous activities or heavy exertion, and everyone else should reduce exposure and strenuous activity, air district officials warn.
The thunderstorm system that came through California on Saturday generated 5,000 to 6,000 lightning strikes, and sparked more than 700 fires, said Daniel Berlant, a spokesman for Cal Fire.
Associate Editor Doane Yawger can be reached at (209) 385-2485 or firstname.lastname@example.org. Modesto Bee reporter Tim Moran contributed to this report.