Pollen
Many people are allergic to pollen, and pollen can be an asthma trigger.
On high pollen days, stay indoors with the windows closed. Using your air conditioner may help to filter outside air coming into the home.
Source: EPA
Antelope, Arden Park, Cameron Park, Carmichael, Citrus Heights, El Dorado, El Dorado Hills, Elk Grove, Elverta, Fair Oaks, Folsom, Galt, Granite Bay, Herald, Loomis, Mather, North Highlands, Orangevale, Penryn, Placerville, Pleasant Grove, Rancho Cordova, Rancho Murieta, Rescue, Rio Linda, Rocklin, Roseville, Shingle Springs, Sloughhouse, Wilton, Woodland