July 17, 2009
Unhealthy ozone concentrations in California, Moderate PM2.5 over the Eastern US.
Most of the country experienced Good ozone concentrations (source:EPA'S Airnow), with Unhealthy concentrations experienced in California (figure above), as expected according to yesterday's AQI forecast discussed by Jaime. The figure below shows the ozone concentration timeseries for several stations in California, which recorded concentrations greater than 75 ppb. Moderate concentarions were experienced in Texas, Oklahoma, Oregon, Idaho, Colorado, Utah, and New Mexico.
PM2.5 concentrations (left panel) reached Moderate levels in several eastern US states as the airmass of the weak cold front east of the I-95 Corridor stalled rising the PM2.5 concentrations, as light winds and humid air allow particles to form easily. This Moderate PM2.5 concentrations may have led to the high AOD recorded by MODIS Terra over the northern Mid-Atlantic states (right figure), as well, Saharan desert dust may have contributed to the AOD readings over the coast of Florida and southwestern Texas.
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