Number sign. Not to be confused with the Chinese character äº, the sharp sign (â¯), the viewdata square (â), the numero sign (â), the equal and parallel to symbol (â) or the game Tic-tac-toe's grid. The symbol # is most commonly known as the number sign, hash, or pound sign.
The poison ivy rash is not contagious. When a person touches the poison ivy leaf, a substance on the surface of the leaf (a resin) rubs off. Over the next 48 to 72 hours the skin reacts to the resin by becoming red and developing bumps and blisters at and around the site where the resin was.
All parts of the plant can give you a rash. If you burn poison ivy, urushiol can attach to smoke particles, which can land on your skin and infect you; worse, you can inhale the toxin, and it can severely damage your lungs. Washing does remove the oil, but it can also spread it. Air alone can not spread the compound.