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E-M:/ MDEQ Extends Smog Advisory to Thursday

MDEQ declares Thursday for smog advisory, in addition
to today...Wednesday.

At 2 PM the most polluted place in the state is Oak Park
in Oakland county at 89 ppb, 1 hr average.   Almost every
monitor in Michigan at this hour is in the 70s and a number
in the low to medium 80s, all 1 hour average.   If this were
Ontario, all of those monitors would be considered to be showing
unhealthy air quality in violation of provincial guidelines.

MDEQ Air Quality Division's Air Monitoring Unit web page with
near real time air quality information has been completely redone
and is really pretty nice.....check it out!!   You can start at the ozone page
and then look at other pollutants as well and the air quality index.


MDEQ Content follows.....



An Ozone Action! Day advisory IS declared for Wednesday, August 20th AND Thursday, August, 21st...


An Ozone Action! Day advisory IS declared for Wednesday, August 20th AND Thursday, August 21st...


Thursday contains the type of forecast discrepancies which can drive a meteorologist crazy. The issue is the timing of a cold front posed to drop down from the northwest during the day Thursday and pass through the region by Friday morning. The hope is that cold front will progress on schedule during Thursday so that our current ozone laden air can be flushed out and replaced by cooler, cleaner Canadian air. At the very least, the desire is that preceding clouds would arrive in time to hamper photochemical reactions before we cross into the “Unhealthy for Sensitive Groups” range.

Unfortunately, many factors are coming into play which cause us to doubt the accuracy of the model projections. First, the low pressure cell spawning the cold front is cutting itself off from the regular west-east upper atmosphere flow. This causes systems to move much slower than the models usually project. Second, the upper atmosphere will be cooling tomorrow despite the warming at the surface. With the high humidity accompanying high temperatures at the surface, this would normally indicate a good probability for clouds and severe weather outbreaks. However, a hot layer of air separates the hot, humid surface air from the colder, dryer upper atmosphere. This effectively caps the surface air and potentially blocks convective activity.

History has taught us that a weather pattern, as described above, can have good odds of continuing poor air quality. The highest potential, I believe, will occur in Southeast Michigan and the southern counties of West Michigan. So while the atmosphere may cloud up, the potential for elevated ozone remains high enough to cause us to continue the OzoneAction! Day advisories through Thursday for both Southeast and West Michigan.


The good news is that the cold front will eventually pass through the region by Friday morning. High pressure behind the front will funnel in cool, clean, and dry air to set up an extremely pleasant weekend with daytime highs in the upper 70’s and lows in the mid to lower 50’s. As such, we anticipate Thursday will be the last day of the current elevated ozone episode.

Forecast updated:  Wednesday, August 20th by Jim Haywood
Next update:  Thursday, August 21th by Jim Haywood  

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