No Caution Required The sun may be low on the horizon,obscured or below the horizon due to darkness hours.
Guide 0-50 = Good Air quality is considered satisfactory 50-100 = Moderate Air quality is acceptable 100-150 = Unhealthy for Sensitive Groups 150-200 = Unhealthy Everyone may begin to experience health effects 200-300 = Very Unhealthy Health warnings of emergency conditions. 300+ = Hazardous Health alert !
Guide 0-3 = Safe. 3-5 = Caution Required. 6-8 = Fair Skin types Protect yourself. 8-10 = Fair to Dark Skin Risk high sun burn risk. 10+ = High Risk All Skin types very dangerous.