Environmental Engineering Test 1 Nddc Scholarship

(c). 1000

The Earth’s atmosphere extends up to about 1000 km above the surface, though most of the atmospheric mass lies within the first 100 km.

(b) Troposphere

The troposphere is the lowest layer of the atmosphere, extending about 8–15 km, and contains roughly 70% of the atmospheric mass.

(d) none of the above

The upper layer of the atmosphere is called the exosphere, which lies above the thermosphere.

• Troposphere → lowest layer

• Stratosphere → above troposphere

• Mesosphere → above stratosphere

• Thermosphere → above mesosphere

• Exosphere → uppermost layer

(c) photochemical oxidations of organic matter.

This is not a natural source of pollutants; it is a secondary reaction that occurs in the atmosphere due to sunlight acting on primary pollutants.

(a) automobile exhaust

Automobile exhaust is a man-made source of air pollution, while forest fires and bacterial action in soil/swamps are natural sources.

(c) automobile exhaust

Automobile exhaust is the largest contributor to air pollution, especially in urban areas, due to the massive number of vehicles releasing carbon monoxide, nitrogen oxides, hydrocarbons, and particulates.

(c) biological treatment of wastes.

The lagooning process is primarily used for the biological treatment of wastewater, where natural processes involving algae, bacteria, and sunlight help break down organic matter.

(b) 5

For aquatic life to survive, the dissolved oxygen (DO) content in water should not fall below 5 ppm.

(c) carbon monoxide

Carbon monoxide (CO) is the major constituent of air pollutants, primarily released from automobile exhaust and incomplete combustion of fuels.

(d) all (a), (b), and (c).

Sulphur dioxide (SO₂) causes respiratory diseases, leads to acid rain that reduces plant productivity, and results in the corrosion of building materials.