Smoke from wildfires burning in northern California and southern Oregon drifted over the Monterey Bay Area Tuesday and has degraded air quality in parts of Monterey, San Benito, and Santa Cruz counties.
The Monterey Bay Air Resources District (MBARD) said concentration of smoke has reached levels of the Air Quality Index (AQI) that are moderate or unhealthy for sensitive groups in some areas. Air quality will be variable and unpredictable as conditions change depending on wind and fire activity, MBARD said.
Meanwhile, around the San Francisco Bay Area, the Bay Area Air Quality Management District issued an air quality advisory through Wednesday because of the smoke. Officials advised people to stay indoors, wear a mask when going outdoors, and to use air conditioners to recirculate air if driving.
The smoke is not expected to exceed national health standards or prompt a Spare the Air alert, AQI said.
The National Weather Service said a developing low pressure system inland, combined with a high pressure system over the ocean and a lingering fog bank has allowed high altitude smoke to mix down to the surface. As the inversion reestablishes itself over the region Wednesday, it will trap smoke already at the surface. However, meteorologists say an increased onshore flow should abate the smoky conditions and bring a noticeable improvement to local air quality Thursday and Friday.
The NWS also said to expect seasonal temperatures, with coastal temperatures ranging from the mid 50s to the upper 60s, and inland temps ranging from the low 50s to the low 80s.
Watsonville weighed in at 131 in the Air Quality Index (AQI) at 10am Wednesday. AQI puts 50-100 as moderate, 100-150 as unhealthy for sensitive groups and 150-200 as unhealthy.