SOUTH COAST AIR QUALITY MANAGEMENT DISTRICT DAILY AIR QUALITY FORECAST VALID: WED., DEC. 17, 2025 -------------------------------------------------------------------------------- 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 32 24 0.7 43 22 54 75 2 NW Coastal LA 30 26 0.8 40 18 28 68 3 SW Coastal LA 35 32 1.0 41 18 43 68 4 S Coastal LA 39 27 1.4 42 19 46 69 5 Southeast LA Co 36 23 1.1 43 27 48 84 6 W San Fernando Vly 37 36 1.1 36 15 42 62 7 E San Fernando Vly 31 28 1.0 42 14 47 60 8 W San Gabriel Vly 41 31 0.9 42 14 43 60 9 E San Gabriel Vly 32 27 0.7 37 17 48 66 10 Pomona Walnut Vly 38 25 0.8 49 29 48 88 11 S San Gabriel Vly 34 22 0.9 43 29 45 88 12 S Central LA Co 41 28 0.8 42 23 37 77 13 Santa Clarita Vly 38 36 0.4 37 11 23 55 15 San Gabriel Mts 36 32 0.8 41 11 45 55 Los Angeles County: Mojave Desert Air Basin 14 Antelope Vly 35 34 0.6 33 15 12 62 Orange County: South Coast Air Basin 16 N Orange Co 33 22 0.8 54 28 37 86 17 Central Orange Co 32 21 1.2 43 25 27 81 18 N Coastal Orange Co 36 23 1.2 40 16 41 64 19 Saddleback Vly 37 27 0.5 54 20 35 71 20 Central Coastal 30 23 0.7 36 30 32 90 21 Capistrano Vly 36 26 0.5 43 31 32 92 Riverside County: South Coast Air Basin 22 Norco/Corona 42 28 1.0 73 37 40 105 23 Metro Riverside Co 44 27 1.1 85 40 40 112 24 Perris Vly 39 30 0.8 60 22 43 75 25 Lake Elsinore 47 37 0.5 31 17 32 66 26 Temecula Vly 44 40 0.5 31 7 29 39 27 Anza Vly 47 42 0.4 34 6 28 39 28 Hemet/San Jacinto 43 39 0.7 46 14 41 60 29 Banning 42 38 0.7 39 11 33 55 -------------------------------------------------------------------------------- -------------------------------------------------------------------------------- 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 48 45 0.3 48 17 27 66 Riverside County: Mojave Desert Air Basin 31 E Riverside Co 35 31 0.3 33 6 20 33 San Bernardino County: South Coast Air Basin 32 NW San Bernardino Vly 36 24 0.9 31 22 48 75 33 SW San Bernardino Vly 38 23 1.0 70 36 50 102 34 C San Bernardino Vly 40 31 0.9 54 23 54 77 35 E San Bernardino Vly 39 32 0.9 70 14 45 60 36 W San Bernardino Mtns 38 29 0.8 40 12 48 56 37 C San Bernardino Mtns 49 35 0.9 51 6 47 47 38 Big Bear Lake 39 36 0.8 46 11 43 55 San Bernardino County: Mojave Desert Air Basin 39 Phelan 41 38 0.7 37 7 39 39 40 Hesperia 36 34 0.8 38 7 44 42 41 Trona 34 28 0.4 26 6 12 33 42 Victorville 40 37 0.7 38 9 37 50 43 Yucca Vly 43 38 0.4 38 7 30 39 44 Barstow 37 26 0.6 38 8 42 44 45 Twentynine Palms 35 32 0.4 37 6 27 34 -------------------------------------------------------------------------------- -------------------------------------------------------------------------------- AIR QUALITY FORECAST -------------------------------------------------------------------------------- ON WED., DEC. 17, 2025, THE SOUTH COAST AIR QUALITY MANAGEMENT DISTRICT PREDICTS THE AIR QUALITY WILL BE ... GOOD in the following area(s): Central Mojave Desert AQI: 39 PM2.5 Northern Mojave Desert AQI: 44 PM2.5 Temecula/Anza Area AQI: 39 PM2.5 Victor Valley AQI: 50 PM2.5 MODERATE in the following area(s): Antelope Valley AQI: 62 PM2.5 Banning Pass Area AQI: 55 PM2.5 Big Bear Lake AQI: 55 PM2.5 Coachella Valley/Low Desert AQI: 66 PM2.5 Coastal Area AQI: 90 PM2.5 Hemet/Elsinore Area AQI: 75 PM2.5 Inland Orange County AQI: 92 PM2.5 Metropolitan Area AQI: 86 PM2.5 San Bernardino Mountains AQI: 56 PM2.5 San Fernando/Santa Clarita Valleys AQI: 62 PM2.5 San Gabriel Mountains AQI: 55 PM2.5 San Gabriel Valley AQI: 88 PM2.5 UNHEALTHY FOR SENSITIVE GROUPS in the following area(s): Riverside Valley AQI: 112 PM2.5 San Bernardino Valley AQI: 102 PM2.5 ------------------------------------------------------------------------ ------------------------------------------------------------------------ WEATHER FORECAST ------------------------------------------------------------------------ Night and morning coastal low clouds with locally dense fog are expected, followed by partial clearing. Weak onshore flow brings slight cooling inland, though temperatures remain above normal. Inversion Base: 486 FT | Breaking Temperature: 72 DEG F Inversion Breaking: YES | Maximum Mixing HEIGHT: 2077 FT ------------------------------------------------------------------------ ------------------------------------------------------------------------ AIR QUALITY FORECAST RULE IMPLICATIONS ------------------------------------------------------------------------ Area 40 - South Coast Air Basin: NO-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: Prohibited in South Coast Air Basin Below 3000 ft 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 WEDNESDAY, DECEMBER 17, 2025 IN THE SOUTH COAST AIR BASIN.