Which of the following scientists are associated with the greenhouse effect?

State whether the following statements are true or false:
$(1)$ Severe respiratory diseases in children are caused by $NO_2$ gas.
$(2)$ Carbon monoxide binds with hemoglobin in the blood to form a carboxyhemoglobin complex.
$(3)$ The carboxyhemoglobin complex is $100$ times more stable than the oxygen-hemoglobin complex.
$(4)$ The $pH$ of rainwater is around $5.6$.

Smog is primarily caused by the presence of which of the following?

Which scientist first compared the Earth's atmosphere to a greenhouse effect,and when?

The main cause of air pollution in large cities is ........

Pure water would have a $BOD$ value of