As per the world health organisation (WHO) specification, the maximum permissible concentration (i.e., TLV) of particulate matter in air is __________ ?g/m3.(?g-microgram)
Options
A. 10
B. 90
C. 800
D. 750
Correct Answer
90
Environmental Engineering problems
Search Results
1. Pick out the wrong statement
Options
A. Low ozone layer thickness in polar regions is due to cold climatic conditions
B. Amount of unburnt hydrocarbons emitted by two stroke petrol engine is more as compared to that emitted by a four stroke engine.
C. Carbon monoxide present in the two stroke petrol engine exhaust is much less as compared to that emitted from a four stroke engine.
D. Mercury as a pollutant can enter the blood stream & the digestive system/ lungs and is responsible for causing minamate disease.
8. 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
Options
A. neutralised by alkali treatment.
B. left as such without any treatment.
C. diluted with fresh water to reduce its acidity.
9. 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