Gases and particles which are put into the air or emitted by various sources are called?

Possible Air pollution, I'm not exactly sure but i think that might be the closest answer i found. I'm am truly sorry if this is not the answer! here is a little description about air pollution just in case.

 Pollutants can be in the form of solid particles, liquid droplets, or gases. ... Usually, primary pollutants are substances directly emitted from a process, such as ash from a volcanic eruption, the carbon monoxide gas from a motor vehicle exhaust or sulfur dioxide released from factories.

The answer is joseph is observing the colour of the reaction mixture to see whether proteins are present in the given solution.

Wikipedia aswell can be used to solve the following questions