SOUTH COAST AIR QUALITY MANAGEMENT DISTRICT DAILY AIR QUALITY FORECAST VALID: THU., SEP. 17, 2026 -------------------------------------------------------------------------------- SRA AREA 1-HR 8-HR 8-HR 24-HR 24-HR 1-HR MAX NUMBER OZONE OZONE CO PM10 PM2.5 NO2 AQI PPB PPB PPM UG/M3 UG/M3 PPB -------------------------------------------------------------------------------- Los Angeles County: South Coast Air Basin 1 Central LA Co 49 41 1.0 17 9 23 50 2 NW Coastal LA 41 37 0.2 17 6 17 34 3 SW Coastal LA 36 33 0.2 16 7 6 39 4 S Coastal LA 47 41 0.2 16 7 19 39 5 Southeast LA Co 47 41 0.6 17 8 19 44 6 W San Fernando Vly 56 47 0.3 17 7 16 44 7 E San Fernando Vly 55 48 0.6 18 9 19 50 8 W San Gabriel Vly 50 43 0.3 20 10 12 53 9 E San Gabriel Vly 60 54 0.4 23 11 18 55 10 Pomona Walnut Vly 59 51 0.3 31 10 24 53 11 S San Gabriel Vly 49 42 0.3 21 9 16 50 12 S Central LA Co 45 39 0.2 16 8 15 44 13 Santa Clarita Vly 64 54 0.2 18 9 15 50 15 San Gabriel Mts 57 50 0.3 31 10 24 53 Los Angeles County: Mojave Desert Air Basin 14 Antelope Vly 56 53 0.2 21 11 29 55 Orange County: South Coast Air Basin 16 N Orange Co 49 44 0.2 25 8 11 44 17 Central Orange Co 44 40 0.3 15 7 16 39 18 N Coastal Orange Co 44 40 0.2 15 5 17 37 19 Saddleback Vly 46 42 0.2 25 5 16 39 20 Central Coastal 43 40 0.2 15 5 14 37 21 Capistrano Vly 40 38 0.2 22 5 12 35 Riverside County: South Coast Air Basin 22 Norco/Corona 55 49 0.4 36 9 18 50 23 Metro Riverside Co 61 50 0.7 40 10 17 53 24 Perris Vly 61 56 0.4 31 8 18 54 25 Lake Elsinore 48 45 0.2 14 7 11 42 26 Temecula Vly 41 38 0.2 31 6 11 35 27 Anza Vly 49 47 0.2 37 9 11 50 28 Hemet/San Jacinto 51 48 0.3 30 7 17 44 29 Banning 57 53 0.3 29 7 11 49 -------------------------------------------------------------------------------- -------------------------------------------------------------------------------- SRA AREA 1-HR 8-HR 8-HR 24-HR 24-HR 1-HR MAX NUMBER OZONE OZONE CO PM10 PM2.5 NO2 AQI PPB PPB PPM UG/M3 UG/M3 PPB -------------------------------------------------------------------------------- Riverside County: Salton Sea Air Basin 30 Coachella Vly 63 58 0.2 48 16 12 64 Riverside County: Mojave Desert Air Basin 31 E Riverside Co 43 39 0.2 32 9 10 50 San Bernardino County: South Coast Air Basin 32 NW San Bernardino Vly 54 47 0.3 35 14 15 60 33 SW San Bernardino Vly 55 48 0.3 37 11 21 55 34 C San Bernardino Vly 67 57 0.3 36 10 24 58 35 E San Bernardino Vly 68 57 0.6 34 10 21 58 36 W San Bernardino Mtns 60 51 0.3 33 11 21 55 37 C San Bernardino Mtns 68 60 0.3 35 7 24 67 38 Big Bear Lake 59 53 0.3 32 6 21 49 San Bernardino County: Mojave Desert Air Basin 39 Phelan 60 55 0.3 28 7 24 51 40 Hesperia 68 58 0.3 28 8 25 61 41 Trona 54 49 0.2 33 6 19 45 42 Victorville 68 58 0.3 28 8 25 61 43 Yucca Vly 56 52 0.2 33 10 18 53 44 Barstow 58 54 0.2 26 9 33 50 45 Twentynine Palms 51 48 0.2 33 9 16 50 -------------------------------------------------------------------------------- -------------------------------------------------------------------------------- AIR QUALITY FORECAST -------------------------------------------------------------------------------- ON THU., SEP. 17, 2026, THE SOUTH COAST AIR QUALITY MANAGEMENT DISTRICT PREDICTS THE AIR QUALITY WILL BE ... GOOD in the following area(s): Banning Pass Area AQI: 49 Ozone Big Bear Lake AQI: 49 Ozone Coastal Area AQI: 39 PM2.5 Inland Orange County AQI: 39 PM2.5 Metropolitan Area AQI: 50 PM2.5 Northern Mojave Desert AQI: 50 PM2.5 San Fernando/Santa Clarita Valleys AQI: 50 PM2.5 Temecula/Anza Area AQI: 50 PM2.5 MODERATE in the following area(s): Antelope Valley AQI: 55 PM2.5 Central Mojave Desert AQI: 53 PM2.5 Coachella Valley/Low Desert AQI: 64 PM2.5 Hemet/Elsinore Area AQI: 54 Ozone Riverside Valley AQI: 53 PM2.5 San Bernardino Mountains AQI: 67 Ozone San Bernardino Valley AQI: 60 PM2.5 San Gabriel Mountains AQI: 53 PM2.5 San Gabriel Valley AQI: 55 PM2.5 Victor Valley AQI: 61 Ozone ------------------------------------------------------------------------ ------------------------------------------------------------------------ WEATHER FORECAST ------------------------------------------------------------------------ High temperatures will remain as much as 5 to 10 degrees below average. Night and morning coastal low clouds will spread inland across much of the valleys. Inversion Base: 3119 FT | Breaking Temperature: 82 DEG F Inversion Breaking: NO | Maximum Mixing HEIGHT: 4070 FT ------------------------------------------------------------------------ ------------------------------------------------------------------------ AIR QUALITY FORECAST RULE IMPLICATIONS ------------------------------------------------------------------------ Area 40 - South Coast Air Basin: BURN Area 53 - Mojave Desert Air Basin: BURN Area 55 - Salton Sea Air Basin: BURN Beach Fire Ring Wood Burning: Allowed in All Areas Residential Wood Burning: Allowed in All Areas Coachella Valley Rule 403.1 Wind Forecast: Winds Below 25 MPH ------------------------------------------------------------------------ ATTENTION ALL SCHOOLS AND INDUSTRIES THIS IS THE SOUTH COAST AIR QUALITY MANAGEMENT DISTRICT NO AIR POLLUTION OR HEALTH ADVISIORY EPISODES ARE PREDICTED FOR THURSDAY, SEPTEMBER 17, 2026 IN THE SOUTH COAST AIR BASIN.