What is the difference between a Health Watch and a High Pollution Advisory?
A “Health Watch” means the highest concentration of pollution may approach the federal health standard. Unusually sensitive people should consider reducing prolonged or heavy outdoor exertion during a health watch. “High Pollution Advisory” or “HPA” means the highest concentration of pollution may exceed the federal health standard. Active children, adults and people with lung disease such as asthma should reduce prolonged or heavy outdoor exertion. Maricopa County employers enlisted in the Trip Reduction Program are asked to activate their HPA plans on high pollution advisory days.
