U.S. Air Quality

Moderate Air Quality in Eastern U.S. and Southern California; Atlantic Hurricane Season Begins

There were widespread readings of Code Yellow (Moderate) air quality across the much of the eastern portion of the nation today, as seen in the loops of PM2.5 (below on left) and ozone (below on right) AQI values. PM2.5 conditions were also Code Yellow in southern California.

AOD levels were slightly elevated in the Southeast today, as shown by the MODIS Terra image for EPA Region 4 (below on left). Some light haze associated with the elevated AOD values is evident in the corresponding MODIS Terra true color image (below on right, overlaid with AQI values in Google Earth).

Yesterday was the beginning of the Atlantic hurricane season, which runs from June 1 to November 30. As Meloë noted in her post last week, we’ve already seen the first tropical depression form, although it did not develop into a named tropical storm. In their annual Atlantic hurricane season outlook, issued on May 21, NOAA predicted a “near-normal” hurricane season, including a 70% chance of 9-14 named storms, with 1-3 major hurricanes (Category 3, 4 or 5 on the Saffir-Simpson Hurricane Scale). Incidentally, the National Hurricane Center is debuting a new experimental Saffir-Simpson Wind Scale this year, which is designed to be less potentially misleading than the existing Saffir-Simpson Hurricane Scale in conveying to the public the damage that a hurricane might inflict upon landfall. The experimental Wind Scale will only include information on peak winds in the tropical system and will not include descriptions of storm surge ranges, flooding impact, or central pressure. Stay tuned to the Smog Blog throughout hurricane season, as we will keep you updated on any tropical systems that form and monitor the potential impacts on air quality in the U.S.