Q. Acute danger to human life (i.e. death) exists, if the concentration of CO₂ in atmospheric air exceeds __________ percent (by volume).

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Q. Methyl iso-cynate (MIC) gas (TLV <1 ppm), which caused Bhopal gas tragedy in 1984 falls under the category of __________ toxic gas.

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Q. Noise level heard inside a bus in busy city traffic or inside a sub-way train corresponds to about __________ decibels.

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Q. Workers working in __________ industry are most prone to white lung cancer.

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Q. A standard test for determination of hardness in water is termed as __________ test.

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Q. TLV of lead for public sewer/waste water is about __________ ppm.

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Q. Presence of nitrates in water in excess of 50 ppm causes

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Q. In sewage treatment, the detention period allowed for oxidation ponds ranges from __________ weeks.

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Q. The maximum permissible noise level to which a man working in a chemical plant can be exposed for eight hours per day is about __________ decibels.

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Q. The most commonly used chemical coagulant in water treatment is

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Q. The biological decomposition of organic substances in wastes controlled conditions is called

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Q. Lung cancer & DNA breakage are the major ill effects of excessive ozone exposure to human beings. Ozone layer depletion in the atmosphere is mainly caused by the presence of

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Q. Smog is not formed due to the presence of __________ in the atmosphere.

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Q. Pick out the correct statement.

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Q. Which of the following is not a source of ozone emission in the atmosphere ?

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Q. Oceans act as sinks for atmospheric gases including carbon dioxide whose concentration in the atmosphere is increased by the

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Q. Pick out the correct statement.

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Q. The upper layer of atmosphere is called the

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Q. Coal mines drainage waste water (acidic in nature) results from the earth's water percolating through the voids created in coal bed during mining. This polluted water which either drains out naturally to water courses or are removed before starting the mining is

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Q. Fine grit present in sewage is removed in the __________ during sewage treatment.

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