Tropospheric column NO₂ concentrations (molecules/cm2) from the Ozone Monitoring Instrument (OMI) over the South Coast region of California from one day, August 1, 2008.

OMI NO₂ columns averaged over summer months (Jun-Aug) for the years 2005-2008 at 0.025 degree resolution. The satellite's 16 day repeat pattern provides daily measurements which partially overlap allowing an area-weighted average to produce a higher resolution image.

Emission Reductions Show Results

Over the past several years, California has enforced aggressive air quality regulations. Results of this action can be seen in Aura's OMI imagery below. OMI shows that decreases in nitrogen dioxide (NO₂) columns over the 4 years 2005-2008 approach 40%, almost the same as the weekend decrease observed in 2005.

Vehicles have a much smaller impact on local air quality than they did 20 years ago, but their emissions of heattrapping gases have continue. Mobile sources including passenger vehicles account for approximately half of California's global warming pollution.