In April, the city of Los Angeles failed an important air quality test, which could be surprising after the COVID-19 pandemic, when most of us weren’t driving around.

So why is LA’s air so bad?

Five things you need to know:

  1. The American Lung Association’s air quality report gave the counties in Southern California an 'F,' making LA the worst in the U.S. 
  2. Smog — the yellowish shroud that often hangs over us — is actually ozone. There is good ozone, which is high above us in a layer where it’s more naturally occurring and protects the earth from getting too much UV radiation, and there is bad ozone — human-made, low on the ground and extremely bad for you. Bad ozone can cause asthma attacks, strokes, heart attacks and even lung cancer.
  3. So how does it happen? Generally, nitrogen oxide (NOx) from car exhausts and volatile organic compounds (VOCs) from gasoline and solvents mix together, and on hot, cloudless, sunny days, the sun's rays hit them to cause a photochemical reaction that creates ozone. Cities like LA make it worse because they’re semi-basin, which traps the ozone and keeps it there.
  4. The culprit is a complex mix of things. It is estimated that nearly 40% of our country's imports come through the LA area, transported, of course, by fossil fueled vehicles that put particles in the air. These can lead to smog.
  5. Throw in the hottest heat waves and particles from wildfire smoke, and that’s why we’ve had one of the worst ozone years in nearly a 1/4 of a century. 

Scientists suggest cutting back on fossil fuels, especially for transportation and zero emissions for all vehicles. The bigger picture, however, has to do with our climate, drought and forest fires.