Who is affected? Everyone, but the elderly, the young and those with health problems are more susceptible to health effects.
Safety tips: Stay indoors as much as possible. Put off exercising outdoors. Don't mow the lawn. If you must work outside, take frequent breaks.
If you need help: Call a doctor if you experience shortness of breath, wheezing, coughing or unusual fatigue.
When will it be over? The haze could clear out sometime Tuesday but may return later this week, depending on the wind.