1) Why do traffic policeman wear masks at crowded crossroads??
2) How do plants and animals maintain the balance of oxygen and CO2 in the air ( or in theatmosphere)???
Plants take carbon dioxide to prepare food and release oxygen during daytime. This oxygen is taken in by animals and carbon dioxide is released. Thus, plants and animals help in maintaining balance of oxygen and carbon dioxide.
Traffic policemen wears mask to protect himself from the polluted air coming from the vehicles that may enter this nose and lead him to serious problems.
The photo above is from a raid in Ann Arbor, Michigan. “Police officers dressed in black and wearing masks executed a search warrant at MedMar about noon, seizing computers, cash, boxes, plastic bags and other items.’
Setting aside all the other issues, why would law enforcement need to wear masks? I have to say that if they showed up at a local homestead people might think they were robbers. That seems not only dangerous for the accused but for the police as well. This makes the action look like it was being carried out by a thuggish third world dictator instead of happening in a democracy.