# Presentation: 745065

## Saharan Dust Event Impacts on Florida Particulate Concentrations

- 2007 National Air Quality Conference
- Orlando, Florida
- February 12, 2007
- Tammy Eagan
- Meteorologist, Florida Department of Environmental Protection

## July 24, 2005, Sunday

- Saharan dust impacts to Florida are documented in many ways, including spectacular images from satellite, but even these images do not quantify how much and what kind of particles will travel to the state, expected on Tuesday.

## Sunrise, Sunset

## Lift of Dust Storm

- This is Phoenix, but the image is similar to a Saharan dust storm, and it is through this lifting that the coarse particles are able to enter the trans-Atlantic winds and travel to Florida.

## PM10 From Around the State

**Notes:**
The graph of PM10 from sites around the state clearly show that a wide-scale high concentration event occurred on June 23, 2004

## The Old Method of Detection

**Notes:**
Manual PM10 filters have always shown clearly in their colors, the impact of Saharan dust by the distinctive reddish-brown color. In the PM2.5 data, the speciation analysis allows for a more objective identification of days with an influx of Saharan dust.  Investigation of these events show that the PM2.5 for Saharan dust contains elevated aluminum concentrations.  On June 23rd, the aluminum is over 30 times the average annual concentration.

## The New Method of Detection

**Notes:**
This graph shows PM10, and PM2.5 graphed at 1/10 scale for ease of comparison with the aluminum concentration.  The spike in aluminum concentration is an indication of Saharan dust and is rarely present at significant levels throughout the year.

## A fine look

**Notes:**
In the graph of the PM2.5 from sites around the state, the impact of Saharan event is not as clear. In fact the highest concentrations of the year occurred in Miami on New Year’s Day, followed by the Fourth of July, both elevated concentrations were attributable to fireworks. 

## Saharan PM10 and PM2.5 

**Notes:**
General assumptions hold that the Saharan dust that crosses the Atlantic is fine particulate (PM2.5).  If true, any increase in levels of PM10 would be completely accountable in the PM2.5 concentration since PM10 includes all of PM2.5 plus the coarse fraction of particles from 2.5 to 10 micrometers.  Looking at the day before and day after the largest impact, the PM2.5 concentration averaged 12.7 mg/m3.  Analogously, the PM10 averaged 28.1 mg/m3. The day of the impact, the PM2.5 concentration rose to 23.8 mg/m3, showing an approximate excess over the previous and following day of 11.1 mg/m3.  Therefore, the expected increase in PM10 concentration would be about 11.1 mg/m3 and the expected concentration would be about 39.2  mg/m3.  

## Only One Example

**Notes:**
However, the actual concentration for June 23rd is 78.8 mg/m3, an under estimate of 39.6 mg/m3.  This discrepancy can only be explained by acknowledging that in addition to an influx of fine particles from the Sahara, Florida is impacted by slugs of coarse particles as well.

## Travel time

- June 17, 1999 TOMS and July 2, 1999
- One to two week travel time is common
- From Laboratory for Atmospheres TOMS Project, NASA Goddard Space Flight Center

## Lift of the Storm

- This image, taken April 29, 2005 by Sgt. Shannon Alredge at Al Asad in western Iraq near the Syrian and Jordanian boarder, shows the power of a desert dust storm.
-  This tempest reached 1.6 kilometers into the sky.  It is that reach that allows the dust to enter the trans-Atlantic winds and travel to Florida.

## Contact Information

- Tammy Eagan
- Florida Department of Environmental Protecton
- (850)921-9567
- Tammy.Eagan@DEP.State.FL.US