That could be pheromones.
Yes, they do, and it can attract others to the area.
...Cycle of life
Skunks are most commonly known to emit a terrible odour. Tasmanian devils also emit a pungent odour when disturbed.
Internal combustion engines don't emit cloroflorocarbons, but they do emit hydrocarbon's. Hydrocarbons are/is unburned fuel which can be caused by a number of things,but it all leads back to unburned fuel.
Light doesn't emit light, but other things do, like stars for example. Many things give off light, but white light is the only visible light, and is made up of many different colors, like a rainbow. The sun and other stars emit such light.
Things that shine - emit light - through biological processes. Fireflies etc
Electromagnetic radiation is emitted from many different things. Some of the things that emit electromagnetic radiation are microwaves, x-rays and radios.
No. They emit no odor and of cause being inanimate object they can not smell things themselves.
All objects and living things emit infrared radiation unless the object is not a black hole as well unless its temperature is not at the Absolute Zero ( I would call it an "infrared black hole") - such an object can only absorb infrared radiation.
you can find it IN chemical reactions. NH4cl emit NH3 while heating.
Yes - many things emit infrared radiation (IR), including toasters.
Yes, all living things vibrate. You are vibrating right now.