Write down the effect of particulate pollutants on the environment. 

What is smog? How is classical smog different from photochemical smogs ? 

Given below are two statements :

Statement $I$ : If $BOD$ is $4\,ppm$ and dissolved oxygen is $8\,ppm$, then it is a good quality water.

Statement $II$ : If the concentration of zinc and nitrate salts are $5 ppm$ each, then it can be a good quality water.

In the light of the above statements, choose the most appropriate answer from the options given below :

Define environmental chemistry.

What do you mean by green chemistry? How will it help decrease environmental pollution?