You are correct. It seems he fell prey to a pretty common rumor...
https://www.stripes.com/blogs-archi...ing-the-air-at-kandahar-1.151166#.XrMbIijYrrc
If you’re the type of person who enjoys filling your lungs with crisp, clean air, then Afghanistan would fit your definition of hell on Earth. Rumor is the air quality at Kandahar Air Field is so bad that troops stationed there automatically get a 10 percent disability rating.
Having caught a nasty case of bronchitis in Iraq two years ago, The Rumor Doctor has tremendous sympathy for troops who have to breathe the dust and other nasty stuff in the air downrange, so he decided to investigate.
While no one disputes that air quality in Afghanistan is terrible, you can file the disability rating rumor with other legends about Kandahar Air Field that The Rumor Doctor has already debunked.
“Currently, Kandahar Airfield is not considered an automatic 10 percent disability rating ‘just for being there and breathing the air,’” Maj. Stacy Mosko, preventative medicine officer for the 10th Mountain Division, said in an email.
Mosko also dispelled the notion that you could ever get an automatic disability rating. To get such a rating, troops must have a certified physical problem, and that is only determined after a medical exam, he said.