- A pollutant refers to a substance or form of energy that is introduced into the environment, leading to unintended consequences or diminishing the utility of a particular resource.
- The extent of a pollutant’s adverse impact on human health is determined by its characteristics and concentration.
- Primary pollutants are impurities directly emitted from their original source, examples of which include CO2, SO2, and NO.
- Secondary pollutants are created through the interaction of pollutants like HC, NO, and O3 in the environment (under conditions of moisture and sunlight), resulting in the formation of new substances such as PAN (Peroxyacetyl Nitrate), petrochemical smog, and formaldehyde.
CLASSIFICATION OF POLLUTANTS
Pollutants are classified based on the following criteria:
- Source of Pollution:
- This classification considers the origin or cause of pollutants, distinguishing between industrial emissions, vehicular exhaust, agricultural runoff, and other sources.
- Mode of Release:
- It categorizes pollutants based on how they are released into the environment, whether through point sources (specific, identifiable sources like chimneys) or non-point sources (diffuse sources like agricultural fields).
- Presence in Nature:
- Pollutants are classified based on their natural occurrence or human-induced introduction. Some pollutants are naturally present but become harmful in excessive amounts due to human activities.
- Degree of Degradability:
- This classification focuses on the degradability or persistence of pollutants in the environment. Some pollutants readily break down, while others persist for extended periods, causing long-term environmental impact.
POLLUTANTS- BASED ON SOURCE OF POLLUTION
Primary Pollutants:
- Primary pollutants are directly released into the atmosphere from natural or artificial sources. These pollutants are immediately emitted from the source and maintain their original form in the environment. Examples of primary pollutants include ashes, smoke, fumes, dust, nitric oxide, sulphur dioxide, hydrocarbons, and various other substances.
Secondary Pollutants:
- Secondary pollutants are formed as a result of chemical reactions or physical interactions between primary pollutants or between primary pollutants and other components in the atmosphere. Unlike primary pollutants, secondary pollutants are produced as a result of transformations or reactions involving the main pollutants. Examples of secondary pollutants include sulfur trioxide, nitrogen dioxide, aldehydes, ketones, and ozone. These pollutants are not directly emitted but result from the alteration of primary pollutants through atmospheric processes.
POLLUTANTS – BASED ON DEGREE OF DEGRADABILITY
Non-Degradable Pollutants:
- Decay slowly in the natural environment.
- Accumulate and physiologically magnify as they migrate through the biogeochemical cycle and food chains.
- Remain in complex forms as they are not acted upon by microorganisms.
- Accumulate in nature and persist for a longer time.
- Do not emit foul odor during decomposition.
- Examples include mercury salts, long-chain phenolic compounds, DDT, and aluminum cans.
Degradable/Biodegradable Pollutants:
- Degrade quickly through natural processes.
- Can be acted upon by microorganisms, leading to conversion into inorganic substances.
- Do not accumulate in nature as they are biodegradable.
- Examples include heat or thermal pollution and domestic sewage.
- Emit foul odor during decomposition.
POLLUTANTS- CAUSE
Commercial or Industrial Waste:
- Definition: Waste generated by facilities primarily engaged in business, trade, recreation, education, sport, or entertainment.
- Importance: Proper disposal and management of industrial waste are crucial to prevent environmental pollution and protect human health.
Rapid Urbanization:
- Description: Increasing migration to cities for jobs and affluence, with half of the world’s population already living in cities and a projected two-thirds by 2050.
- Impact: Urbanization can lead to challenges such as increased demand for resources, strain on infrastructure, and environmental degradation.
Fires in the Woods (Wildfires):
- Definition: Uncontrolled and unprescribed combustion or burning of plants in natural contexts like forests, grasslands, brushlands, or tundra.
- Cause: Environmental conditions, such as wind and topography, can contribute to the spread of wildfires.
- Impact: Wildfires can cause significant ecological damage, loss of biodiversity, and contribute to air pollution.
Population Growth:
- Description: Recent global population increase amplifying the effects of agricultural and commercial operations.
- Impact: Higher population puts increased pressure on resources, leading to challenges such as food security, water scarcity, and habitat loss.
Hazardous Waste:
- Definition: Waste with features making it unsafe or harmful to human health or the environment, including liquids, solids, gases, and sludge.
- Sources: Industrial production process wastes and batteries are mentioned as examples.
- Management: Proper disposal and treatment of hazardous waste are critical to prevent adverse health and environmental effects.
Deforestation and Improper Agricultural Practices:
- Definition: Loss of forest land for purposes like agriculture, urbanization, or mining, contributing significantly to global greenhouse gas emissions.
- Impact: Deforestation results in habitat loss, biodiversity decline, and contributes to climate change.
Frequently Asked Questions (FAQs) – Pollutants
1. What is a pollutant?
A pollutant refers to a substance or form of energy introduced into the environment, leading to unintended consequences or diminishing the utility of a particular resource.
2. How does a pollutant’s characteristics and concentration impact human health?
The extent of a pollutant’s adverse impact on human health is determined by its characteristics and concentration.
3. What are primary pollutants?
Primary pollutants are impurities directly emitted from their original source, such as CO2, SO2, and NO.
4. How are secondary pollutants formed?
Secondary pollutants are created through the interaction of pollutants like HC, NO, and O3 in the environment, under conditions of moisture and sunlight, resulting in the formation of new substances.
5. How are pollutants classified?
Pollutants are classified based on the source of pollution, mode of release, presence in nature, and degree of degradability.
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