1. Maximum allowable concentration of CO2 in air for safe working is __________ ppm (parts per million).
2. Tolerable limit of nitrogen oxides in air is __________ ppm.
3. Iron & manganese present as pollutant in water can not be removed by
4. In water chemical treatment plant, use of chloramines ensures
5. Which of the following is the common pollutant emitted from metallurgical smelters, thermal power plant and cement plants ?
6. During which of the following operating conditions of an automobile, carbon monoxide content in the exhaust gas is maximum ?
7. H2S present in gaseous stream can be removed by adsorption on
8. Inhalation of lead compounds present in automobile exhaust (using leaded petrol) causes
9. Replenishment of dissolved oxygen in water stream polluted with industrial waste occurs by
10. Aerodynamic noise resulting from turbulent gas flow is the most prevalent source of valve noise in fluid ilow control. It is caused due to
11. Smoke is produced due to
12. Fluorosis (a bone disease) is caused by the presence of high concentration of __________ in atmospheric air.
13. Threshold Limit Value (TLV) is the maximum allowable concentration (i.e. safe limit) of pollutants in air. Safe limit for SO2 in air is __________ ppm.
14. Main pollutants released from iron & steel industry is
15. Exposure to chemicals having carcinogenic properties cause
16. Scale formation in boiler is controlled by
17. Noise level heard at a distance of about 100 metres from a jet engine with after burner is about __________ decibels.
18. TLV of mercury in potable (drinking) water is about __________ ppm.
19. Which is the best and the most effective method for the removal of organic contaminant present in the polluted water in very small quantity (say < 200 mg/litre)?
20. Which is a secondary air pollutant ?
21. Which of the following is the most detrimental for water used in high pressure boiler ?
22. Turbidity of water is an indication of the presence of
23. Presence of excess flourine in water causes
24. Siderosis is a disease caused by the inhalation of __________ dust.
25. Which of the following pollutants is not emitted during volcanic eruptions ?