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Primary air pollutant in the Sierraville area:
PM2.5 - 75 Moderate
If you are unusually sensitive to particle pollution, consider reducing your activity level or shorten the amount of time you are active outdoors.
Friday, April 4: Calm early morning winds have allowed pollutants to linger in the Portola area. Additionally, as an upper-level ridge of high pressure begins to build along the West Coast, atmospheric mixing will be limited. However, increasing east-northeasterly winds will disperse pollutants and carry a clean air mass into Portola through the midday and afternoon hours. As a result, AQI levels will be low-Moderate. Saturday, April 5: As the upper-level ridge of high pressure strengthens over northern California, warmer temperatures aloft will produce an inversion, inhibiting mixing throughout much of the day. Therefore, despite light to moderate easterly winds dispersing pollutants in the afternoon, AQI levels will remain low-Moderate. Sunday, a strong morning inversion will trap pollutants at ground level in Portola. Additionally, calm winds through the first half of the day will lead to pollutant build-up in Portola. However, light to moderate southwesterly winds will increase dispersion in the afternoon. Therefore, AQI levels will remain mid-Moderate. Monday, the next trough of low pressure aloft will traverse northern California, enhancing atmospheric mixing and producing light to moderate southwesterly daytime winds. However, calm winds will hinder dispersion during the morning and evening, leading to low-Moderate AQI levels. Tuesday, as the trough of low pressure departs to the east, atmospheric stability will increase, reducing mixing over Portola. However, light to moderate southwesterly winds will continue to aid dispersion, keeping AQI levels low-Moderate. Wednesday, an upper-level ridge of high pressure will build over northern California, reducing mixing in the atmosphere. Furthermore, calm to light winds throughout the day will allow pollutants to accumulate in Portola. As a result, AQI levels will increase to mid-Moderate.
Primary Pollutant: PM2.5 - 62 Moderate
Primary Pollutant: PM2.5 - 66 Moderate
Primary Pollutant: PM2.5 - 68 Moderate
Primary Pollutant: PM2.5 - 60 Moderate
Primary Pollutant: PM2.5 - 62 Moderate
Primary Pollutant: PM2.5 - 69 Moderate