[ADEQ Forecasts] ADEQ Daily Air Quality Forecast - Saturday, August 27, 2011

[forecasts@lists.azdeq.gov]

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

Health message for Saturday, August 27: Unusually Sensitive People should consider limiting prolonged exertion outdoors.


Synopsis and Discussion:
...A PM10 HIGH POLLUTION ADVISORY REMAINS IN EFFECT FOR FRIDAY, AUGUST 26, 2011...
FRIDAY'S OZONE HEALTH WATCH HAS BEEN EXTENDED THROUGH SATURDAY, AUGUST 27, 2011
The results are in for yesterday's air quality levels, and their pretty eye opening.  That early morning dust storm caused all but one site to exceed the 24-hr PM10 health standard.  Not only that, but Durango's monitor registered levels in the code BROWN category, which is HAZARDOUS.  That's incredible.  Durango's PM2.5 monitor was the only one to exceed that standard as well, but several others got close, reaching the upper MODERATE range.  Ozone levels exceeded at six monitors with Phoenix Supersite (17th avenue and Campbell) reaching 122 on the Air Quality Index (AQI).  Overall, it was not a good day to be outside in the Phoenix metro area (not to mention the 113°F heat!)
Many ozone monitors are at or below where they were yesterday.  A few are slightly higher.  The good news is that the rate of increase has slowed.  We have an Ozone Health Watch in place for today with the highest concentrations expected to be in the north and northwest part of the Valley, around Cave Creek, Glendale, North Phoenix, and Dysart.  Tomorrow's pattern and levels will be similar to today, so we are extending that Health Watch through Saturday.  With high pressure breaking down Sunday through next week, we will see a shift in winds out of the southwest.  This will not only drop our thunderstorm chances, but also help decrease local ozone levels.
The dust has cleared out nicely as mostly monitors are now showing PM10 concentrations in the GOOD range.  We still have the PM10 HPA in place for today, but that will be allowed to expire at midnight with no further extension.
The latest WRF-RUC model suggests thunderstorms will develop over the Valley tonight around 8pm.  If it does happen, that would be a good thing as rain will clear the air and stabilize the soil.  It's only when the storm originate outside of the Valley the concern of significant dust is raised.
    
Check back on Sunday for the weekend wrap up and a look ahead at next week's weather and air quality.  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