New research has found Los Angeles skies are less smoggy, a sign that emission-control strategies are working.
Scientists analyzing air quality from a recent aircraft campaign and historical data found that ozone pollution in the Los Angeles region has declined over the past few decades. The team also found the air chemistry has changed, leading to a drop in levels of a compound that contributes to eye irritation.
The improved air suggests California's policies to reduce emissions are having an impact. Pollution comes from vehicles, industries and natural sources like plants.
New insights into LA's air came from a large field study in 2010 that relied on aircraft and a research ship to sniff the atmosphere.
The findings are being published in a journal of the American Geophysical Union.