[ADEQ Forecasts] ADEQ Issues High Pollution Advisories for Particulate Matter-10 and Ozone

[forecasts@lists.azdeq.gov]

Health message for Thursday, August 25: People with respiratory disease,
such as asthma, should avoid any outdoor activity; everyone else,
especially the elderly and children, should limit outdoor exertion.

Health message for Friday, August 26: People with respiratory	disease,
such as asthma, should limit outdoor exertion.


...SAME DAY PM10 AND OZONE HIGH POLLUTION ADVISORY FOR THURSDAY, AUGUST
25, 2011...
...THURSDAY'S PM10 HPA IS BEING EXTENDED THROUGH FRIDAY, AUGUST 26,
2011...
...AN OZONE HEALTH WATCH IS BEING ISSUED THROUGH FRIDAY, AUGUST 26,
2011...
An area of disturbance in the stealth of the night generated a wall of
dust that pushed northwest from north of Tucson through Pinal County
(Casa Grande), settling out in northwestern Maricopa County.  That's a
path of more 130 miles.  It took just over 4 hours for the wall of dust
to move through.  In its wake, nearly all of Pinal County's PM10
monitors and several more of Maricopa County's monitors exceeded the
health standard.  This occurred between 1-2am this morning.  Even if
every hour from now until midnight registered completely clean air, the
24-hr average still exceeds.  Thus, we have issued a PM10 High Pollution
Advisory for Thursday.  There's not much anyone can do to prevent
something that has already happened, but there is plenty they can do to
keep it from becoming worse as well as protecting their healthy by
avoiding outdoor exposure today.
Ozone levels were in the 90s of the Air Quality Index (AQI) at several
forecast area monitors on Thursday as well.  That wall of dust that
brought all of the particulates also imported some ozone as well.  Many
Valley monitors are starting 10 to 20 parts per billion (ppb) higher
than 24 hours earlier.  As the sun comes out, addition ozone will be
generated, likely pushing some parts over the Valley above the health
standard for ozone, as well.  Thus, we have also issued a same-day Ozone
HPA for Thursday.
Models are suggesting that we have an increased chance for some
showers/thunderstorms moving in tonight from the southeast.  Along with
this possibility comes the likelihood of more blowing dust.  This will
likely add to today's totals for PM10.  The hold over of lingering dust
Friday morning could be enough to push some Valley monitors over the
edge once more.  So... we are EXTENDING today PM10 HPA through Friday.
Cloud cover Friday morning along with a sustained southeast-to-northwest
flow should result in slightly lower Ozone levels, but we are issuing an
Ozone Health Watch for Friday with the target area of highest
concentrations in the north-central part of the forecast area.

Check back tomorrow for the weekend outlook.  Until then, have a good
day!  -J.Paul


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

For transportation alternatives:
www.valleymetro.org


If you have any questions or comments regarding this forecast please
contact:

Arizona Department of Environmental Quality
Office of Communications
1110 W. Washington St., Phoenix, AZ 85007
(602) 771-2215
ms15@azdeq.gov