The threshold limit of benzene is

Which of the following is/are inorganic gas (es)?

The permissible concentration of PM 10 in the air is

Which of the following is a secondary air pollutant?

The minimum size of smoke particle is

X ray films are a source of which of the following gas?

Which are the sources of arsenic pollution?

Which of the following is a source for boron air pollution?

Which is the major source for sulphur dioxide?

Which is the largest source for production of nitrous oxide?