A few years ago, I passed the swelling body of raccoon roadkill about 100 feet from my driveway. It was mid-summer, so the flies were swarming and the smell was nauseating, even from driving by in a car. Later that day, while I was outside cutting grass, I saw the neighbor woman walk up the road and start dragging it towards her house...with her bare hands.
She only made it about 15 feet before the decomposing leg tore off in her hand.
She tossed it aside and started dragging from another leg. I know this woman owns a shovel. I freaked out and told everyone that I was certain she was keeping a pet zombie and needed the raccoon for food because there was no other reason for retrieving the roadkill. It was hundreds of feet from her house, and there aren't any houses between ours-- just an empty field, so it was perfectly fine decomposing on its own along the road. Once she went home, I'm sure she realized the smell on her hands wouldn't wash away. You see, all decaying flesh smells bad...really bad.
If there really was a zombie apocalypse, survivors would be vomiting profusely. The smell of one dead body, let a lone a flock of dead bodies, would make you instantly vomit. If you tried to avoid this by rubbing Vicks VapoRub inside/ under your nose, you'd be muting one of your best early-warning alert senses, meaning, if there was a zombie coming, you'd smell him before you saw him.
As the bodies decomposed, they'd be bloated with air. The bacteria that feed off of the rotting flesh produce gases and the body's like a multi-layered balloon-- lots of cavities to trap the gasses. The environment will greatly impact this, with hot weather increasing the speed of decomposition. First, sores would appear on the skin and the overall skin would become discolored; then, the ears, nose, and fingers/toes would fall off. Lastly, bones would begin to become exposed, limbs would fall off, teeth would be missing, and the eyes would be lost. Sadly, the second-life expectancy of a zombie would be less than a year, and as time progressed, it would become less and less capable of hunting and feeding.
The two main causes of eau de zombie are cadaverine and putrescine-- compounds produced during the putrification of flesh. Both are toxic, but only in amounts so large that it's doubtful they'd kill you in a zombie apocalypse. These smell so horrid and they'll permeate your clothing and your hair, so you'll carry the scent with you for days.
When the zombie apocalypse hits, there are a few things you'll want to do:
1) Double glove. It's likely you'll be in some sort of hand-to-hand combat with a zombie at one point or another. Your best defense against retaining the zombie smell: wear a pair of nitrile gloves, then place a pair of latex gloves over them. If you have trouble sliding one pair of gloves over the other, try a little powder-- but just a little!
2) Change your clothes, and often. Throw your old ones away after you've worn them. The smell won't wash out of them, and you won't have time to keep trying. It's the zombie apocalypse-- keep your Valentino gown in the closet and raid a Wal-Mart for shite you can wear n' toss.
3) Did one of those slabs of decay touch you? Ugh...take a bath in diluted vinegar. I'd pick pickle scent over putrid any day.
3) Does your hide-out smell from their constant clawing at your boarded up doors and windows? Sprinkle some odor-absorbing materials around: charcoal, baking soda, coffee grounds-- whatever you can scrounge.
4) While you're in the stores looting, don't forget the sticky fly strips! Zombies are the perfect host for bacteria, fungi, and insects! Flies would flourish in these walking opportunities and would create clouds around the zombies from their intense swarms.
