SOUTH COAST AIR QUALITY MANAGEMENT DISTRICT DAILY AIR QUALITY FORECAST VALID: MON., SEP. 21, 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 56 49 1.0 21 9 16 50 2 NW Coastal LA 47 44 0.2 21 8 11 44 3 SW Coastal LA 41 38 0.1 21 8 10 44 4 S Coastal LA 51 48 0.3 20 8 19 44 5 Southeast LA Co 54 48 0.7 21 9 17 50 6 W San Fernando Vly 51 48 0.3 21 9 10 50 7 E San Fernando Vly 58 56 0.6 22 10 13 54 8 W San Gabriel Vly 60 51 0.3 24 11 10 55 9 E San Gabriel Vly 74 60 0.3 26 11 14 67 10 Pomona Walnut Vly 62 51 0.3 32 10 17 53 11 S San Gabriel Vly 59 51 0.4 24 10 16 53 12 S Central LA Co 53 47 0.4 21 9 15 50 13 Santa Clarita Vly 64 55 0.2 23 11 9 55 15 San Gabriel Mts 61 55 0.3 32 11 21 55 Los Angeles County: Mojave Desert Air Basin 14 Antelope Vly 70 63 0.2 27 11 27 77 Orange County: South Coast Air Basin 16 N Orange Co 53 47 0.1 25 8 10 44 17 Central Orange Co 48 43 0.3 19 8 11 44 18 N Coastal Orange Co 45 43 0.3 19 5 16 40 19 Saddleback Vly 46 44 0.2 24 5 12 41 20 Central Coastal 44 42 0.2 18 5 11 39 21 Capistrano Vly 41 40 0.2 25 5 9 37 Riverside County: South Coast Air Basin 22 Norco/Corona 55 50 0.4 30 8 12 46 23 Metro Riverside Co 61 56 0.7 31 10 12 54 24 Perris Vly 59 54 0.4 31 9 13 50 25 Lake Elsinore 46 44 0.2 17 8 8 44 26 Temecula Vly 46 42 0.2 34 6 8 39 27 Anza Vly 56 52 0.2 40 6 9 48 28 Hemet/San Jacinto 55 51 0.3 30 7 13 47 29 Banning 61 56 0.2 30 8 9 54 -------------------------------------------------------------------------------- -------------------------------------------------------------------------------- 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 72 62 0.2 52 8 10 74 Riverside County: Mojave Desert Air Basin 31 E Riverside Co 44 40 0.2 30 5 10 37 San Bernardino County: South Coast Air Basin 32 NW San Bernardino Vly 63 53 0.4 35 12 11 56 33 SW San Bernardino Vly 58 50 0.3 33 10 15 53 34 C San Bernardino Vly 67 59 0.3 34 10 18 64 35 E San Bernardino Vly 65 57 0.5 32 10 17 58 36 W San Bernardino Mtns 65 56 0.3 33 11 23 55 37 C San Bernardino Mtns 68 62 0.2 34 8 27 74 38 Big Bear Lake 61 57 0.2 32 5 25 58 San Bernardino County: Mojave Desert Air Basin 39 Phelan 59 55 0.2 30 7 34 51 40 Hesperia 62 59 0.2 30 8 35 64 41 Trona 56 55 0.2 38 7 16 51 42 Victorville 66 64 0.2 31 9 37 80 43 Yucca Vly 58 55 0.2 30 5 20 51 44 Barstow 68 62 0.2 34 8 47 74 45 Twentynine Palms 52 51 0.2 29 5 19 47 -------------------------------------------------------------------------------- -------------------------------------------------------------------------------- AIR QUALITY FORECAST -------------------------------------------------------------------------------- ON MON., SEP. 21, 2026, THE SOUTH COAST AIR QUALITY MANAGEMENT DISTRICT PREDICTS THE AIR QUALITY WILL BE ... GOOD in the following area(s): Coastal Area AQI: 44 PM2.5 Hemet/Elsinore Area AQI: 50 PM2.5 Inland Orange County AQI: 44 PM2.5 Metropolitan Area AQI: 50 PM2.5 Temecula/Anza Area AQI: 48 Ozone MODERATE in the following area(s): Antelope Valley AQI: 77 Ozone Banning Pass Area AQI: 54 Ozone Big Bear Lake AQI: 58 Ozone Central Mojave Desert AQI: 51 Ozone Coachella Valley/Low Desert AQI: 74 Ozone Northern Mojave Desert AQI: 74 Ozone Riverside Valley AQI: 54 Ozone San Bernardino Mountains AQI: 74 Ozone San Bernardino Valley AQI: 64 Ozone San Fernando/Santa Clarita Valleys AQI: 55 PM2.5 San Gabriel Mountains AQI: 55 PM2.5 San Gabriel Valley AQI: 67 Ozone Victor Valley AQI: 80 Ozone ------------------------------------------------------------------------ ------------------------------------------------------------------------ WEATHER FORECAST ------------------------------------------------------------------------ Below normal temperatures through Wednesday. Deep marine layer and chance of rain. Inversion Base: 3024 FT | Breaking Temperature: 81 DEG F Inversion Breaking: NO | Maximum Mixing HEIGHT: 3656 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 Above 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 MONDAY, SEPTEMBER 21, 2026 IN THE SOUTH COAST AIR BASIN.