Environment Pollution Flashcards
Pollution
It is the excessive addition of material to physical environment making a less fit or unfit for life
Pollutants are materials or factors that cause adverse effect on the natural quality of any component of environment
Classifications
According to form there are two types of pollutants
Primary pollutants like DDT and plastic
Secondary pollutants like peroxyacetyl nitrate
According to the nature of disposal there are biodegradable pollutants (like sewage) and non biodegradable pollutants (plastics, glass, salts of heavy metals and radioactive substances)
According to origin they are natural or anthropogenic
Major air pollutants and their sources
Carbon monoxide:
It is a colourless and odourless gas
Produced by incomplete burning of carbon based fuels like petrol, diesel, wood, etc
Produced from the combustion of natural synthetic products like cigarettes
Lower the amount of oxygen that enters our blood
Slows our reflexes and makes us confused and sleepy
Carbon dioxide:
Principal greenhouse gas emitted as the result of human activities like the burning of coal, oil or natural gas
Chlorofluorocarbons (CFC)
Gas released from AC or refrigeration
It rises the stratospheric temperature when it comes in contact with other gases and reduces the ozone layer
Lead:
It is present in petrol, diesel, lead batteries, paints and hair dye products
It affects children
It causes nervous system damage, digestive problems and even cancer
Ozone:
Occurs naturally in the upper layers of atmosphere
Shields Earth from harmful ultraviolet rays of the Sun
At ground level it is pollutant with highly toxic effects
Major source of ground level ozone emissions are vehicles and industries
Make eyes itch and burn
It lowers our resistance to cold and pneumonia
Nitrogen oxide
Causes smog and acid rain
Produced from burning fuels like petrol, diesel and coal
Nitrogen oxide can make children susceptible to respiratory diseases in the winters
Suspended particulate matter
Consists of solids in air in the form of smoke, dust, vapour, remains suspended for extended periods, is the main source of haze that reduces visibility
Sulphur dioxide
Gas produced from burning coal mainly in thermal power plants
Industrial processes like production of paper and smelting of metals produce Sulphur dioxide
Major contribution to smog, acid rain and lung diseases
Smog
The term was first used by HAD Voeux in 1905
Smoke+ fog
It is hazy ear that causes difficulty in breathing
It is a combination of water vapour and dust
It’s caused by heavy traffic, high temperature, calm winds, etc.
It hampers visibility and harms the environment.
Causes respiratory problems and that’s related to bronchial diseases
Heavy smog decreases UV radiation and the decrease of natural vitamin D production causing rickets
Fly ash
Produced from the combustion of solid material
Residue rises with gases into atmosphere
Very fine powder and tends to travel far in air
Composed of aluminium silicate, silicon dioxide and calcium oxide
Fly ash is captured by electrostatic precipitators or other particle filtration equipments before flue gases reach chimneys of coal fired power plants
If not captured and disposed of properly it can believe the air and water and caused respiratory problems
Fly ash in air slowly settles on and leaves crops in the fields to thermal power plants and lowers plant yield
Causes of pollution:
Uncontrolled growth in human population
Rapid industrialisation
Urbanization
Uncontrolled exploitation of nature
Forest fires
Radioactivity
Volcanic eruptions
Strong winds
Biological pollutants like plants, mite, pet fur, fungi, parasite and bacteria
Formaldehyde
Radon,
Asbestos
Pesticides,
Perfumes
Hair dyes
Furniture polish
Glue
Air freshener
Moth repellents
Wood preservatives
Mercury
Cadmium
Synthetic fibre
Tobacco
Types of air pollution
Natural pollutants
These are released from the natural sources or as a result of natural activity
Some examples are: pollen and volatile organic compounds from plants, hydrogen sulphide etc from volcanic eruptions, etc.
Primary pollutants are emitted directly into the air as a result of natural or human activities like nitrogen oxides, carbon dioxide, carbon monoxide, hydrocarbons and particulates released from furl burning
Secondary pollutants
These are produced as a result of chemical reaction between primary pollutants and normal atmospheric compounds under the influence of electromagnetic radiations from the Sun
For example when sulphur dioxide reacts with oxygen in the atmosphere it forms sulphur trioxide, a secondary pollutant.
Sulphur trioxide further reacts with water vapour to form another secondary pollutant sulphuric acid which is component of acid rain
Indoor air pollution
Refers to the physical chemical and biological characteristics of air in indoor environment within home or institution/commercial facility
For example energy efficiency improvement sometimes make houses relatively air tight and reduce ventilation raising pollution levels
In rural areas, people rely on traditional fuels causing pollution
In urban areas, construction of tightly sealed buildings and reduced ventilation cause pollution
Impact of air pollution on flora and fauna
Effects on vegetation:
Retarded photosynthesis
Sulfur dioxide causes chlorosis, plasmolysis, membrane damage and metabolic inhibition
Hydrocarbons like ethylene lead to premature leaf fall, fruit drop, shedding of floral buds, curling of petals and discoloration of sepals
Ozone damage chlorenchyma and destructs foliage in many plants
Effects on animals:
Deterioration of materials and aesthetic loss
Control measures
Selection of suitable fuel with low sulphur content that is efficient for utilization
Modifications in industrial processes and/or equipments to reduce emission
Selection of suitable manufacturing site and zoning at a distance from residential areas and insulation of chimneys
Destroying pollutants by thermal or catalytic combustion
Conversion of pollutants to less toxic form
Collection of pollutants
Water sprinkling on roads
Smog guns to fight against air pollution
Removal of particulate pollutants from air by arresters and scrubbers
Control of gaseous pollutants through combustion, absorption and adsorption
Control of automobile exhaust by the use of efficient engines like multipoint fuel injection engine, catalytic converter filters in vehicles can convert nitrogen oxide to nitrogen and reduce potential hazards of nitrogen oxide, use of good quality automobile fuels, use of lead free petrol, use of compressed natural gas
Government initiative to control air pollution:
Notification of national ambient air quality standards and sector specific emission and effluent standards for industries
Setting up of monitoring network for assessment of ambient air quality
Introduction of cleaner gaseous fuels like CNG,LPG, ethanol blending etc
Launching of national air quality index composed of 8 pollutants like PMIO, PM2.5, NO2, SO2, CO, O3, NH3, Pb.
Leap frogging from BS-IV to BS-VI standards for vehicle by first April 2020
Banning of burning of biomass
Promotion of public transport network
Pollution under control certificate
Issuance of directions under air (prevention and control of pollution) act of 1981
Installation of online continuous monitoring devices by 17 highly polluting industrial sectors
Regulating the bursting of pollution emitting crackers
Notification of graded response action plan for Delhi identifying source wise action for various levels of air pollution etc
