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E-M:/ New Haven/Muskegon didn't go purple

Yesterday I sent out a message about New Haven and
Muskegon going condition "purple" on ozone and smog
at 7 PM yesterday.

MDEQ's Laura Deguire called today to say that the
Air Division's AQI processor must have an error as
the purple indicator should not have been displayed
and they are looking into why it occurred.

None of this diminishes the fact that yesterday was
a very bad air pollution day.

You can see the highest 8 hour average information at


85 ppb -- 8 hour average is the level of the new health standard.

23 out of 24 MDEQ monitors showed concentrations at or above
85 ppb with New Haven the worst at 110 ppb in northern Macomb

More of this is expected today....see MDEQ forcast below...


An Ozone Action! Day Advisory is in effect for Wednesday, June 25th


An Ozone Action! Day Advisory is in effect for Wednesday, June 25th


OzoneAction! Day advisories will continue through Wednesday for both West Michigan and Southeast Michigan.  The current weather pattern, which brought ozone concentrations greater than the 85 ppb health threshold for nearly all MDEQ monitors on Monday, will continue and even intensify Tuesday and Wednesday.  Each day of this episode, which began Sunday, will yield increasing deterioration of air quality as the accumulation of stagnated air adds to the problem.  The combination of high pressure in the southeast quadrant of the country with low pressure in the northern plains will continue to pump hot, humid air tainted with upwind urban pollution into the state.  There is good agreement with all the models that Wednesday temperatures will approach the mid-90’s in the inland portion of the state as sunshine remains abundant.  To make matters worse, dew points will approach the 70 degree mark to add to the misery index.  It will be almost certain that nearly all MDEQ monitors will continue to show air quality in the “Unhealthy for Sensitive Groups” range with the possibility that some monitors may even exceed the more severe “Unhealthy” threshold (e.g. 105 ppb).


Air quality will continue to deteriorate through Wednesday as winds stay predominately southwest and ample sunshine will continue to promote widespread atmospheric photochemical reactions.  Relief is forthcoming but not until Thursday when a cold front approaches the region.  We will review the latest model predictions Wednesday morning to determine if the approaching frontal system could stall and conclude if any OzoneAction! advisories are warranted for Thursday.  In the meantime, individuals susceptible to elevated ozone concentrations and/or high temperature/humidity should continue to limit their outdoor exposure to protect their health.

Forecast updated: Tuesday, June 24rd by Jim Haywood

Next update: Wednesday, June 25th by Jim Haywood

For issues related to forecasting contact: MDEQ, Modeling and Meteorology Unit

Alex J. Sagady & Associates        http://www.sagady.com

Environmental Enforcement, Permit/Technical Review, Public Policy,
Evidence Review and Litigation Investigation on Air, Water and
Waste/Community Environmental and Resource Protection
Prospectus at:  http://www.sagady.com/sagady.pdf

PO Box 39,  East Lansing, MI  48826-0039 
(517) 332-6971; (517) 332-8987 (fax); ajs@sagady.com