Pensacola Bay, in the panhandle of Florida, is about 115 nautical miles from the site of the BP disaster. Nautical miles are slightly larger than statute miles, or the miles you are used to measuring on land.
On land, 115 nautical miles would be the same as 132 statute miles. In a car, it takes more than two hours to cover that distance. That's the distance from Washington, DC to Philadelphia. Toledo is closer than that to Cleveland. Sacramento is closer than that to San Francisco.
If something was burning in Cleveland, the folks in Toledo would be surprised to see it show up in their city. If something was spilled in Philly, you wouldn't expect to smell it in Washington. If something fouled the air in San Francisco, you wouldn't expect it to hurt people in Sacramento.
I make the point because our friends at the EPA have been measuring the levels of benzene, toluene, and xylene in the air along the shore of the Witch's Brew formerly known as the Gulf of Mexico. If you look at their numbers for the area around Pensacola Bay it is clear the concentrations of these compounds in the air have increased substantially over the last few weeks.
First, a tale of two images. These come from the EPA's site, where they publish the data from their mobile Trace Atmospheric Gas Anaylzer. As the EPA explains:
The TAGA monitors have been conducting two types of monitoring:
•air toxics found in crude oil that may evaporate from the spill into the air, and
•chemicals from dispersants that have the highest potential to get into the air in any significant amounts.
The first image shows their route along Alabama's coast and Florida's panhandle on July 5th of 2010:
The black line marks the route of the mobile air sampling unit. The white portions of that line mark areas where aromatic hydrocarbons were detected in the air. Compare the first image to a similar image from a couple weeks back (June 24, 2010):
The change around West Pensacola is slight, but noticeable. It is unclear if the affected area has grown or merely moved across the mouth of the bay. There also appears to be an increase in detected pollutants along the shore by Orange Beach. However, the biggest change is to the East around Santa Rosa Sound.
These images simply represent locations where pollutants were detected in the air. They don't say anything about the concentration of pollutants. For that information, you have to look at the data the EPA provides.
The changes in concentration are clearly seen when you compare the data from July 5 (warning, csv file) to the data from June 24. The greatest concentrations measured are centered around Pensacola Bay. If you map the coordinates provided in the data, you can pinpoint the locations where the data was collected. The area covered by these coordinates is shown below:
When you compare the numbers between the two sampling runs, the differences are striking. This bar chart compares the average numbers from the two sampling runs:
Although there is no significant increase in the benzene levels measured, there are dramatic increases in both toluene and xylene levels. The toluene levels have increased 7-fold, while xylene levels increased 10-fold.
It's no wonder the local Pensacola paper reported
Oil cleanup workers outnumbered the beach goers Wednesday afternoon (July 7,2010) on the beach outside the entrance to Ft. Pickens as workers kept busy picking up tar balls and removing bags of oil-contaminated sand.
It is important to note the reported levels for aromatic hydrocarbon pollutants are well below the OSHA guidelines for acceptable workplace exposure. However, these numbers are still disturbing. In the first place, there has been very little storm activity. Second, there has not been a lot of rain. In other words, this is the stuff that has shown up with light breezes 115 nautical miles away from the accident. People working closer are obviously being exposed to much higher levels. The reason I am documenting this now is I expect these numbers will continue to climb the further we get in to summer. It will be interesting to see if the EPA continues providing the data if things get much worse.