El Niño has quickly become a household name, and its effects can be felt throughout the South Coast Air Basin. From very warm temperatures and increased humidity to warmer ocean water and higher tides, El Niño can influence weather conditions across Southern California. But what could it mean for air quality?
El Niño is a weather pattern that occurs when ocean temperatures in the central and eastern Pacific become warmer than normal, influencing atmospheric circulation and weather patterns around the globe. According to the National Oceanic Atmospheric Administration (NOOA), El Niño is strengthening and has a greater than 90% chance of becoming a very strong event during fall and winter 2026-27. *
For Southern California, one potential impact is increased rainfall during the winter. More rain can be good news for air quality because precipitation helps remove airborne particles and pollutants from the atmosphere. Storm systems can also bring stronger winds and atmospheric mixing that helps disperse accumulated pollution.
Typically, rainfall is associated with decreases in ozone and fine particulate matter (PM2.5), two pollutants that can affect public health. However, the relationship between weather and air quality is complex, and El Niño does not guarantee specific weather or air-quality conditions. Temperature, wind, rainfall and atmospheric conditions can all influence pollution levels.
Whatever El Niño brings this winter, residents can stay informed by checking local air quality before heading outdoors and signing up for air quality alerts at aqmd.gov or downloading the South Coast AQMD app.
* https://www.cpc.ncep.noaa.gov/products/predictions/long_range/fxus05.html?ftag=YHF4eb9d17&utm_source