Uno mas dias.
We flew our last research flight here in Mexico yesterday, and it was a banner flight for many instruments. One of the people on board measures SO2, and he reported a concentration of 300 ppb at one point as we flew over a refinery just south of Mexico city, and later he figured that it might be closer to 500 ppb after he did a calibration. This is very VERY high! CN spiked at the same time, as did sulfuric acid, and we could even smell the pollution in the cabin.
I got some great pictures that show the pollution really well:
Here you can see the haze that obscures the mountains in the background, as well as the contrast between it and the blue sky above. Just below the clouds is the massive layer of pollution that we were approaching.
Now we're over Mexico city, and we could barely see the ground due to the pollution. Just below us the ground was somewhat visible, and a little further away was almost completely obscured.
Here we are not far above the downtown area, and you can JUST make out the skyscrapers in the upper half of this photo.
And finally, contrast that against this last picture, where we are out of the pollution to the east of Mexico City, and can actually see a few layers of mountains off in the distance.
So today I am packing up both my personal belongings and our equipment for the shipment home. I am to fly on the ferry back to Jeffco in Boulder, which means that I don't need to get up at 0400 for the 0700 departure on the once-daily Continental flight that goes through Houston. Ours is a direct 4 - 5 hour flight, mostly at altitude, with only some of the instruments running due to a very short 15-minute preflight warm-up. Then I have two (2!) weeks and two days before I ride the ferry up to Seattle for INTEX-B. I'd better get packing...