() With nearly 3000 acres burning in Califonia, health experts say N95 respirator masks offer the best protection against harmful wildfire smoke, provided they are worn correctly and fit properly.

The masks, readily available at hardware stores and pharmacies, can filter out fine particles found in smoke that can irritate eyes, nose, throat and lungs, according to public health officials.

However, they do not protect against hazardous gases sometimes present in smoke.

Health officials emphasize that proper fit is crucial. The mask should have two straps that go around the head, seal tightly to the face, and be certified by the National Institute of Occupational Safety and Health.

Single-strap paper dust and surgical masks do not adequately protect from wildfire smoke.

The most effective protection remains to stay indoors and limit outdoor activity during smoky conditions. Those who must be outside should take frequent breaks, as breathing through respirator masks requires more effort.

Health officials warn that masks should be discarded when breathing becomes difficult, if they become damaged, or if the inside becomes dirty. They also note that respirator masks are not approved for children and will not work effectively for people with facial hair.