Maybe he's been eating a lot of cheese or just has very rotten breath.
Depends on where you smell it. If it's your breath, it can be a sign of diabetes. More info, please.
it is so coz particles in air are constantly moving
Car exhaust can smell like rotten eggs when the fuel has a lot of sulphur in it.
One regular drink containing an ounce of alcohol will make your breath smell.
Sulfur and Hydrogen
Sulfur is the component in gunpowder that produces a smell similar to rotten eggs when it is burned.
samonella, extract
If an automobile battery is in normal condition, there should be very little smell from it. The one smell that you should be aware of is the smell of rotten eggs, which indicates severe and dangerous problems with the battery. Once a battery begins to smell like rotten eggs, it cannot be saved, but must be immediately replaced. Please be aware that rotten-egg batteries can explode. Rotten-egg batteries are frequently much hotter than normal batteries would be, and the hot rotten-egg batteries are the most dangerous. The most common cause of rotten-egg batteries is an alternator which constantly overcharges, so the alternator should usually be replaced along with the battery.
It makes your breath smell fine and dandy.
Some farts smell of rotten eggs because they contain Hydrogen Sulphide - which is what gives rotten eggs their smell!
proscuitto shouldn't smell rotten, it should smell salty and just a bit meaty.