U.S. Air Quality

Moderate Air Quality Continues in Midwest; Mostly Good Conditions Elsewhere

Code Yellow (Moderate) PM2.5 air quality continued in the Midwest today, while conditions were mostly in the Code Green (Good) range across the rest of the country, as shown in the loop of PM2.5 AQI values (below on upper left). NOAA's Hazard Mapping System (HMS) Fire and Smoke product indicates that a thin layer of residual smoke from fires in British Columbia is lingering over the Midwest; this smoke may be contributing to the Code Yellow conditions at the surface. The smoke is not visible in the Terra MODIS true color image for the region (below on lower left, overlaid with AQI values in Google Earth), and MODIS AOD is not elevated (below on lower right), which supports HMS's report that the smoke is thin.

Along the East Coast, a coastal low pressure system is keeping temperatures unseasonably low and air quality in the Good range. In California, the Station fire in Los Angeles is still burning 157,220 acres with 56% contained, according to the National Interagency Fire Center. Smoke from the Station fire is visible in today's Terra MODIS true color image (below on left, overlaid with AQI values in Google Earth), but air quality seems to be well in the Code Yellow-to-Green range today across the Los Angeles area, which is good news. A new fire, the Oasis fire, has broken out north of San Francisco; it is burning 400 acres with 15% contained. Smoke from Oasis is visible in today's Terra MODIS true color image (below on right, overlaid with AQI values in Google Earth).

Looking ahead to Wednesday, PM2.5 air quality conditions are likely to persist in the Good-to-Moderate range. Forecasters have issued an Ozone Air Quality Action Day for the Houston, Texas, area, as ozone levels are expected to reach Code Orange (Unhealthy for Sensitive Groups). Code Orange ozone is also forecast for the Sacramento, California, metropolitan region and parts of southern California.

Posted by Amy Huff at September 8, 2009 7:02 PM