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E-M:/ PM 2.5 episode more widespread in Michigan today



PM 2.5 air pollution episode more widespread in Michigan today
and intensifying at some sites

Dearborn area predicted for Code Red today.   At 2 PM
Dearborn is nearly Code Red at 62.8 ug/M3

At 2 PM, the following monitoring sites are at Code Orange conditions:
Allen Park, Bay City, Dearborn, Flint, Grand Rapids, Houghton Lake,
Kalamazoo, Lansing, Port Huron, Ypsilanti.

Note the AQI listing at MDEQ's site has some understated reports
for Grand Rapids, Lansing and Kalamazoo.    Look at the
PM 2.5 Maps page for accurate report of air quality concentration...
....anything over 40.5 is "Code Orange"

http://www.deqmiair.org/pmmaps.cfm
(COLORS ON THIS MAP DON'T REPRESENT AIR QUALITY INDEX)

AIR QUALITY INDEX AT
http://www.deqmiair.org/index.cfm?page=home&sFlush=no
WITH UNDERSTATING ERRORS AT 2 PM FOR GRAND RAPIDS, LANSING AND KALAMAZOO

EPA's PM 2.5 Airnow site, national pm 2.5 view
http://www.airnow.gov/index.cfm?action="">

look at the screen at the bottom for an hour by hour display since midnight

EPA Airnow PM 2.5 forecast for Michigan
http://www.airnow.gov/index.cfm?action="">
Go here to get to EPA Airnow Midwest view and time series
http://www.airnow.gov/index.cfm?action="">

MDEQ OFFICIAL PM 2.5 FORCAST INFORMATION FOLLOWS:
========================================================
Forecast Summary: Monday, November 27th, 2006 through Monday, December 4th, 2006

PM-2.5: 24-hr concentrations are expected to be mostly High Moderate to Unhealthy for Sensitive Groups (USG) through Wednesday then Moderate on Thursday and mostly Good through the remainder of the forecast period.

Forecast Discussion:

The forecast week begins with PM-2.5 concentrations running in the Unhealthy for Sensitive Groups (40.5 -- 65.4 ug/m3) range for many of the state's monitors. The Dearborn monitor is running very near the Unhealthy threshold (65.5 ug/m3) and may well cross into that category during Monday and Tuesday. The weather feature responsible for our elevated fine particulate is a stationary front running through the mid to northern portion of the lower peninsula. Warmer temperatures, weak southerly winds and high relative humidity over the past few days have contributed heavily to increasing PM-2.5 concentrations. This trend is likely to persist through Wednesday before any significant changes occur.

Monday's PM-2.5 concentrations will likely be the worst for the week as light winds retard any potential mixing and atmospheric dilution. Although our next strong frontal system will not arrive until Thursday, winds will begin to increase during mid-day Tuesday in advance of that approaching system. The increasing winds should encourage atmospheric mixing and help hold higher particulate concentrations in check. Whether or not that atmospheric mixing is enough to reduce concentrations depends on the depth of the polluted layer of the atmosphere. Monday's upper air sounding shows our current mixing layer to be fairly deep which means the polluted layer of the atmosphere is also likely to be fairly deep. Without significant sun, I do not expect any thermal mixing and Tuesday's increased wind speeds may not be enough to counter decreasing air quality. Bottom line is that the PM-2.5 concentrations will likely not experience any significant improvement until the next fontal passage on Thursday. There may be some slight improvement late Tuesday and Wednesday, but at best, I expect High Moderate to Low USG to rule most of the lower portion of the state.

The models currently have the projected frontal system pushing through the area sometime on Thursday. The timing of the front varies with each model but passage should occur by Thursday night. Clean (and cold) air will filter in behind the front effectively ending this episode of poor air quality.

Extended Forecast:

Northerly winds should prevail during the rest of the forecast period keeping the region in Good air quality although temperatures will likely run cooler than normal.

Forecast updated by Jim Haywood: Monday, November 27th, 2006

Next forecast update: Monday, December 4th, 2006

Forecast Protocol




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