SANTA CLARITA (CNS) – While fire crews are making progress in their battle against the raging Sand Fire, health officials warned that because of smoke from the blaze, air quality was expected to remain bad in the area for the next two days.

County health officials said air will be unhealthy for everyone in the Santa Clarita, San Fernando and Antelope valleys and the San Gabriel Mountains.

The South Coast Air Quality Management District extended a smoke advisory until midnight Thursday for portions of the Santa Clarita Valley and the San Gabriel Mountains. The agency urged residents in those areas to stay indoors, and to avoid using swamp coolers or wood-burning appliances.

Health officials urged people living or working in the Santa Clarita, Antelope and San Gabriel valleys and the San Gabriel Mountains with heart disease, asthma or other respiratory conditions to minimize outdoor activities.