(Yuba-Sutter, CA) — Asthma and allergy sufferers in the mid-valley may notice an increase in symptoms this week as weather and emissions combine to reduce air quality.

An area of high pressure has dominated the weather over Northern California for the past few days. And prolonged stretches of stagnant air can lead to increased pollution levels in the Valley. In general, air quality in the Valley is at its worst from late evening through early morning. Conditions gradually improve from late morning through the late afternoon.

Anyone sensitive to reduced air quality should avoid strenuous activity during the early morning, late evening and overnight hours. And, For those with spring allergies, expect an increase in tree, grass and weed pollen this week as milder afternoons bring some vegetation out of winter dormancy.