The last time we talked I was under the influence of fart gas. So please don't take too much of it to heart. A lot has changed since then. I had my sphincter insured for four bucks in case it ever goes haywire again. I would recommend doing the same if you want to avoid breathing the brown air.
I don't really know why fart gas has that effect on me. When I was a kid I didn't fart at all. Not until I was seven. I am guessing that the lack of breathing farts means my tolerance never built up. My body chemistry is such that the methane in farts has the same effect as nitrous oxide (laughing gas) has in other people.
I was in the Cub scouts the first time I was subjected to severe fart intake. We were on our first camping trip and I had to sleep with Artie "The Ox" Pifgenoe. The pup tent was very confining. As soon as the zipper went up, Artie's ass began screaming. Farts were tearing out. They weren't used to being out in the open so they found the first place they could to go back into hiding. My nose. I was huffing so much fart that my face turned blue.
Then I started laughing. My stomach cramped up so hard that I fractured a rib. I was laughing and laughing. It hurt so bad that I was crying. And The Ox stayed asleep. Luckily the Scout Master heard me and tore the tent open with a machete and dragged me into fresh air. I was chopper lifted to the hospital so that the doctors could study me.
The doctors found nothing wrong with me. I was put through test after test but they all came up unconclusive. Eventually the psychologist did a thorough analysis on me and traced my problem back to my parents.
Apparently, before I was born, my Dad has such intestinal problems that he was always leaking fart gas. My Mom, in order to survive, built up antibodies in her system that neutralized the gas before it even reached her smelling sense. When I was growing in her stomach, I had zero exposure to fart gas. Though I do remember playing with a tapeworm.
In addition to my lack of exposure to fart, the psychologist found something else interesting. The sound of a fart had just as much effect on me as the actual fart gas. All I had to do was hear a fart and my brain chemistry would produce a laughing effect. I was put under a cat scan while listening to a tape of dog farts and they plotted my brain activity. Sure enough, the farts produced the same effect as someone huffing a tank full of NOX.