Environmental Engineering Test 1 Nddc Scholarship

While 'growth' is a general term, a sudden and rapid increase in the number of individuals in a species within a short period is specifically termed a population explosion. This often occurs when resources become abundant or when significant improvements in healthcare and sanitation drastically reduce the mortality rate while birth rates remain high.

Thomas Malthus, in his 'Essay on the Principle of Population,' theorized that the human population grows in a geometric ratio (2, 4, 8, 16...), while the food supply only increases in an arithmetic ratio (1, 2, 3, 4...). He argued that this disparity would eventually lead to 'Malthusian catastrophes' like famine, disease, or war unless population growth was checked.

An air pollutant is a substance in the air that can have adverse effects on humans and the ecosystem. While Carbon dioxide (\(CO_2\)) is a natural part of the atmosphere, its excessive release from burning fossil fuels makes it a major pollutant responsible for global warming. Note that ground-level ozone and CFCs are also pollutants, but in general ecological contexts, \(CO_2\) is the primary concern for atmospheric change.

From a biological and environmental perspective, noise is defined as unwanted sound. It does not necessarily have to be loud to be classified as noise; any sound that is disruptive, annoying, or physically painful to the listener can be considered noise pollution, potentially leading to stress, hearing loss, and sleep disturbances.

Soil erosion is a primary cause of land degradation where the fertile topsoil is removed by water or wind. While deforestation and waterlogging contribute to the problem, the actual loss of the physical soil structure and its nutrients (erosion) is the most direct cause of the land becoming unproductive or 'degraded'.

Biochemical Oxygen Demand (BOD) is a measure of the amount of dissolved oxygen that aerobic microorganisms (microbes) need to decompose the organic matter present in a water sample at a specific temperature. High BOD levels indicate that the water is heavily polluted with organic waste, which can deplete oxygen and suffocate aquatic life.

Eutrophication is the process where a water body becomes overly enriched with minerals and nutrients (like nitrogen and phosphorus). This extra nourishment leads to the excessive growth of algae (algal blooms), which eventually die and decompose, depleting the water's oxygen and causing the death of other aquatic organisms like fish.

Photochemical smog is a type of air pollution produced when ultraviolet light from the sun reacts with oxides of nitrogen (\(NO_x\)) and volatile organic compounds (VOCs) in the atmosphere. This reaction creates a brownish haze containing secondary pollutants like ozone and PAN, which are harmful to human health and vegetation.

Marble is composed of calcium carbonate (\(CaCO_3\)). When sulphur dioxide (\(SO_2\)) is present in the air, it can react with water to form sulphuric acid (acid rain). This acid reacts with the marble, essentially dissolving the stone and causing significant structural damage over time through a process often called 'stone leprosy'.