[ADEQ Forecasts] ADEQ Extends Air Pollution Health Watch through Wed., Dec. 5

[forecasts@lists.azdeq.gov]

Health message for Tuesday, Dec 04: Unusually sensitive people should
consider reducing prolonged or heavy exertion.

Health message for Wednesday, Dec 05: Unusually sensitive people should
consider reducing prolonged or heavy exertion.

Synopsis and Discussion
TODAY'S PM-2.5 HEALTH WATCH HAS BEEN EXTENDED THRU WEDNESDAY DECEMBER 05
Taking a look a Monday's particle pollutant data indicates that
approximately 31% of the total particulate matter measured at the
Durango monitoring site during the 24-hour period consisted of PM-2.5
(fine particles) while at the West Phoenix site it was a whopping 46%.
The presence of these fine particles in such high ratios contributed to
reductions in visibilities to <10 miles at some valley airfields at
times on Monday and again this morning.  Local ACARS soundings this
morning revealed the presence of a phenomenally strong (nearly 12 deg C
or 21 deg F) surface-based radiation inversion that reaches all the way
to 3900+ feet AGL.  This is the strongest such local inversion recorded
at ADEQ since archiving began in October 2003; the next closest in
magnitude was the 10.4 deg C inversion on December 24 2005.   Hourly
PM-2.5 concentrations are elevated again this morning and average near
30ug/m3 thru 9:00 a.m. at several sites.  Although the very strong ridge
aloft currently overhead will begin to weaken on Wednesday, the
low-level air mass will remain quite stagnant.  In addition, the arrival
of mid and high cloud cover by the afternoon may offset the hoped-for
improvement in dispersion due to a slight increase in wind speeds and
mixing depths.  As a result, the PM-2.5 Health Watch has been extended
thru Wednesday as a continued precaution for those with heart or lung
disease.  -Reith

For more information, please visit our Web page:
http://www.azdeq.gov/environ/air/ozone/ensemble.pdf

**********************************************************************
NOTICE: This e-mail (and any attachments) may contain PRIVILEGED OR 
CONFIDENTIAL information and is intended only for the use of the specific 
individual(s) to whom it is addressed.  It may contain information that is 
privileged and confidential under state and federal law.  This information 
may be used or disclosed only in accordance with law, and you may be 
subject to penalties under law for improper use or further disclosure of the 
information in this e-mail and its attachments. If you have received this e-
mail in error, please immediately notify the person named above by reply e-
mail, and then delete the original e-mail.  Thank you.