21. Which of the following method is adopted for the measurement of NO2 in air?
- Chemiluminescence’s
- Beta attenuation
- Non-Dispersive Infra Red Spectroscopy
- Gravimetric
22. Which one of the following pairs of pollutants is formed due to photochemical reactions?
- CO and RSPM
- O3 and PAN
- PAN and NH3
- NH3 and CO
23. Which of the equipment is used for controlling gaseous pollutants in air?
- Cyclone air separator
- Bag house filter
- Electrostatic precipitator
- Wet scrubber
24. When is a photo chemical smog formed?
- Air stagnation
- High concentrations of hydrocarbon and nitrogen
- Both a and b
- None of these
25. Coal based thermal power stations pollute the atmosphere by adding
- NOx and SO2
- NOx, SO2 and SPM
- NOx, SO2, SPM and CO
- NOx, SPM and CO
26. A list of air pollutants is given below:
- Sulphur dioxide
- Carbon monoxide
- Radioactive substances
- Sulphuric acid
Which of these are ‘primary’ pollutants?
- i and ii only
- i, ii and iii only
- iii and iv only
- i and iv only
27. The most significant gaseous air pollutant is
- CO2 (Carbon-dioxide)
- O2 (Oxygen)
- SO2 (Sulphur-dioxide)
- Nitrogen
28. Which one of the following is a secondary pollutant of air?
- Sulphur dioxide
- Nitrogen oxide
- Peroxy acetyl nitrate
- Hydro-carbons
29. One of the following is not a primary pollutant in air.
- Volatile organic compounds
- PAN
- Oxides of Nitrogen
- Suspended particulates matter
30. Two primary air pollutants are
- Sulphur oxide and ozone
- Nitrogen oxide and peroxyacetyl nitrate
- Sulphur oxide and hydrocarbon
- Ozone and peroxyacety nitrate