The first five months of 2026 in Southern California have been the smoggiest — with the highest number of unhealtful air days — in more than a decade, according to statewide air monitoring. So far this year, the South Coast air basin, which includes Los Angeles, Orange, Riverside and San Bernardino counties, has seen 39 days when the concentration of lung-irritating ozone (commonly known as smog) exceeded the federal standard, according to preliminary state air quality data. That’s even worse than the infamously hot and hazy 2017, when Greater Los Angeles had 36 unhealthful air days by June 4 and ultimately saw 145. Many of the roughly 18 million people who live in the air basin have been subjected to unhealthful levels of ozone, a highly corrosive gas that triggers asthma attacks and a wide range of respiratory illnesses. This has taken many by surprise since successive days of smog more commonly happen in summer, when heat waves and intense sunlight convert man-made pollution into ozone. “If we have this many violations by this time, …