Environmental Engineering Test 1 Nddc Scholarship

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

Higher CO₂ concentration allows shortwave solar radiation in, absorbs and reflects longwave infrared radiation, and traps heat, leading to global warming.

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

Deforestation, industrialization, and increased transportation all release greenhouse gases, thereby accentuating the greenhouse effect.

Global warming may result in:
(d) all (a), (b) and (c)

Global warming increases the risk of floods, cyclones, and reduced food production.

Ozone is:
(b) a secondary pollutant

Ozone is formed secondarily in the atmosphere by photochemical reactions involving primary pollutants like NOx and hydrocarbons.

The term smog is a portmanteau of the words smoke and fog. It refers to a type of intense air pollution that reduces visibility. Modern smog, such as photochemical smog, is often a mix of nitrogen oxides, sulfur oxides, and organic compounds that react with sunlight, but the traditional definition remains the combination of smoke and fog.

Aerosols are defined as a suspension of fine solid particles or liquid droplets in air or another gas. Because they are extremely small (often less than \(1\mu m\)), they have a very low settling velocity and can remain suspended in the atmosphere for long periods, allowing them to be transported globally by wind currents.

[Image showing the difference between primary and secondary air pollutants]
Primary pollutants are emitted directly from a source, while secondary pollutants form in the atmosphere through chemical reactions. Sulphur dioxide (\(SO_2\)) is a primary pollutant because it is released directly from volcanic eruptions and industrial processes (like burning coal). Ozone and photochemical smog are secondary pollutants formed by reactions involving sunlight and nitrogen oxides.

Particulates include any solid or liquid particles suspended in the air. Dust, mists, smoke, fumes, and soot are all physical particles. Even photochemical smog contains a high concentration of particulate matter (like peroxyacetyl nitrates and secondary organic aerosols). Therefore, all the listed options are types of particulates.

While industrial and domestic burning contribute to CO levels, automobile exhaust is the primary source of carbon monoxide in most urban environments. It is produced by the incomplete combustion of carbon-based fuels (gasoline/diesel) in internal combustion engines.

The term carcinogenic literally means "cancer-causing." Hydrocarbons like benzene and polycyclic aromatic hydrocarbons (PAHs) are known to damage DNA and lead to the development of cancer. While they can also cause respiratory issues, their specific classification as 'carcinogens' directly links them to oncology.