Water and Air Pollution

5.1 Fecal-Oral Infection Transmission Route 208020762072

The fecal-oral transmission route is the pathway through which pathogens from the feces of an infected person reach the mouth of a new host, causing diseases such as cholera, typhoid, dysentery, diarrhea, hepatitis A, and polio. This is a major mode of disease transmission in developing countries like Nepal where sanitation and hygiene are inadequate.

5.1.1 The F-Diagram 208020762072

The transmission follows these pathways from infected feces:

1. Fluids (Water): Contaminated water used for drinking, cooking, or washing
2. Fields (Soil): Open defecation contaminates soil; crops grown on contaminated land
3. Flies: Houseflies carry pathogens from feces to exposed food
4. Fingers: Unwashed hands after defecation transfer pathogens to food, utensils, or directly to mouth
5. Food: Contaminated food prepared with unwashed hands or washed with polluted water

5.1.2 Primary & Secondary Barriers 2080

Primary Barriers (prevent pathogens from leaving the fecal environment):

• Sanitary latrines/toilets: Prevent feces from reaching the environment
• Proper sewage disposal: Contained sewerage systems prevent ground and water contamination
• Safe excreta disposal: Pit latrines, septic tanks, composting toilets

Secondary Barriers (prevent pathogens from reaching the new host):

• Water treatment: Boiling, chlorination, filtration of drinking water
• Hand washing with soap: Before eating and after defecation
• Food hygiene: Proper cooking, covering food, washing vegetables
• Fly control: Covering food, using screens, keeping clean surroundings
• Health education: Awareness about personal and community hygiene

The fecal-oral group of infections are diseases transmitted when pathogens in the feces of an infected person are ingested by another person through contaminated water, food, or hands. These diseases are prevalent in areas with poor sanitation and unsafe water supply.

5.1.3 Common Fecal-Oral Diseases

• Cholera: Caused by Vibrio cholerae; severe watery diarrhea and dehydration
• Typhoid: Caused by Salmonella typhi; prolonged fever, abdominal pain
• Dysentery: Bloody diarrhea caused by Shigella or Entamoeba histolytica
• Hepatitis A & E: Viral liver infections transmitted through contaminated water/food
• Poliomyelitis: Viral infection affecting the nervous system
• Diarrhea: Multiple pathogens; leading cause of death in children under 5 in Nepal
• Intestinal worms: Roundworm, hookworm, whipworm — through soil contamination

Prevention: Safe water supply, proper sanitation (toilets), hand washing with soap, food hygiene, health education, and fly control are the key measures to break the fecal-oral transmission cycle.

Pathogens transmitted via fecal-oral route:

• Viruses: Hepatitis A & E virus, Polio virus, Rotavirus (causes viral diarrhea in children, known as "stomach flu")
• Parasites: Entamoeba histolytica, Giardia, Cryptosporidium, Microsporidia (unicellular); Roundworms, tapeworms, pinworms (intestinal worms)
• Bacteria: Campylobacter, Salmonella, Shigella (food poisoning/traveler's diarrhea), Clostridium difficile (antibiotic-associated diarrhea), Salmonella typhi (typhoid fever), Vibrio cholerae (cholera), Toxoplasma gondii

Key transmission concepts:

• Auto-infection: Transmission of microbes from one's own stool back to oneself
• Fomites: Various objects (utensils, toys, surfaces) capable of carrying microbes from contaminated hands
• Routes: Contaminated hands (shaking hands, changing diapers, gardening, handling pets), contaminated food (raw fruits/vegetables), contaminated drinking water (lakes, swimming pools, tap water in low-hygiene areas), and houseflies

5.2 Preventive Measures 2076

Preventive measures to control the transmission of fecal-oral infections can be categorized into:

5.2.1 Safe Water Supply 2076

• Provision of piped, treated water supply
• Water treatment at household level — boiling, filtration (ceramic/bio-sand filters), chlorination, SODIS (Solar Disinfection)
• Protection of water sources from contamination (well covers, spring protection)

5.2.2 Sanitation

• Construction and use of sanitary latrines — pour-flush, VIP latrines, eco-san toilets
• Proper sewage collection and treatment systems
• Community-Led Total Sanitation (CLTS) programs, Open Defecation Free (ODF) zones

5.2.3 Personal & Food Hygiene

• Hand washing with soap at critical times (after toilet, before eating, before food preparation)
• Proper food handling — cooking thoroughly, covering food, washing fruits/vegetables
• Use of clean utensils and safe food storage

5.2.4 Environmental Sanitation

• Solid waste management — proper collection and disposal
• Drainage improvement to prevent stagnant water
• Vector control — fly screens, insecticide spraying, keeping surroundings clean

5.2.5 Health Education

• Community awareness programs on hygiene and sanitation
• School health programs
• Mass media campaigns on safe water and sanitation

5.3 On-Site Sanitation Including Eco-Sanitation

On-site sanitation refers to systems that collect, store, and treat human excreta at the point of generation, without connection to a centralized sewer network. These are especially suitable for rural areas, peri-urban settlements, and areas where centralized sewerage is impractical or too costly.

5.3.1 Types of On-Site Sanitation Systems

1. Pit Latrines: Simple pit (traditional), Ventilated Improved Pit (VIP) latrines with fly screens and vent pipes to reduce odor and flies
2. Pour-Flush Latrines: Water-seal latrines with a U-trap that prevents flies and odor; connected to a soak pit or twin-pit system
3. Septic Tanks: Underground chambers where sewage undergoes anaerobic digestion; effluent goes to a soak pit or drain field
4. Composting Toilets: Dry toilets where feces are decomposed aerobically with added carbon material (ash, sawdust)

5.3.2 Dry System

A dry toilet operates without flush water. Features:

• Requires no water to function — prevents underground water pollution
• Functions as a composting toilet; separates all fluids at source ensuring dry pit conditions
• Suitable for urban, peri-urban, and rural areas; weather resistant, reliable and hard-wearing
• Easily constructed with minimum maintenance; pit lifespan increases to 20–40 years if maintained correctly

Advantages: Saves water (useful in water-scarce/costly areas), prevents pollution of surface/groundwater, enables safe reuse of excreta after composting/drying.

Challenges: No water seal — odors may be a problem; pits are very difficult to empty safely when full.

5.3.3 Wet System

Waste is diluted with a flush of water. Example: septic tank system. Features:

• Requires water to function; prevents underground water pollution
• User friendly, accessible and adaptable (disabled, elderly, children can use it)
• Odorless and free from flies

Advantages: Free from flies and odors, increases standard of life, decomposes solid waste easily, controls spreading of diseases.

Challenges: Repairs to pipes, removing sludge from septic tanks, maintaining stabilization ponds, wastes water in water-scarce areas.

5.3.4 Eco-Sanitation (ECOSAN)

Eco-sanitation is a closed-loop sanitation process in which human excreta is recycled, rendered safe, and used for agriculture. Its main objective is to prevent pollution from happening rather than to control it after it happens, and to minimize the use of non-renewable resources. The key principles are:

• Prevention of pollution: Rather than disposing of excreta into waterways
• Sanitization of excreta: Through composting, dehydration, or storage to destroy pathogens
• Safe reuse: The sanitized product is used as fertilizer in agriculture (closing the nutrient loop)

Objectives of Eco-Sanitation:

• Reduction in the transmission of pathogens from human excreta into the human cycle
• Promotion of safe, hygienic recovery and use of nutrients, organics, water, and energy
• Preservation of soil fertility, improvement of agricultural productivity and food security
• Energy reduction in fertilizer production; substitution of mineral fertilizer
• Improvement of health condition of society and minimization of water pollution

5.3.5 Types of Eco-Sanitation Toilets

• Urine-Diverting Dry Toilet (UDDT): Separates urine and feces; feces are dried/composted, urine is diluted and used as fertilizer
• Twin-Pit Alternating Toilet: Two pits used alternately; when one is full, it is sealed and contents are composted while the other is used
• Biogas-Linked Toilet: Excreta fed into a biogas digester producing methane for cooking and digested slurry for fertilizer

Advantages of Eco-Sanitation:

• Minimal water requirement
• Nutrients (N, P, K) recycled back to agriculture
• No groundwater contamination
• Suitable for water-scarce and flood-prone areas
• Reduces dependency on chemical fertilizers

5.4 Importance of Health Education 20732072

Health education is the process of informing and motivating people to adopt healthy practices, prevent diseases, and improve their quality of life. It is a critical component in water and sanitation programs, especially in developing countries like Nepal.

5.4.1 Importance of Health Education

• Behavioral change: Promotes adoption of healthy habits such as hand washing, safe water storage, and use of toilets
• Disease prevention: Awareness about waterborne diseases reduces incidence of cholera, typhoid, diarrhea, and dysentery
• Community participation: Educated communities actively participate in sanitation programs (CLTS, ODF campaigns)
• Sustainability: Knowledge ensures proper maintenance of water supply and sanitation infrastructure
• Reduces child mortality: Education about ORS (Oral Rehydration Solution), breastfeeding, and nutrition saves lives
• Women empowerment: Health education particularly benefits women and girls regarding menstrual hygiene, maternal health, and family planning

5.4.2 Status in Nepal 2073

Health education in Nepal is extremely poor due to:

• Low literacy rate
• Poor health services and accessibility of health stations
• Unscientific and unhealthy superstitions
• Lack of sense of responsibility in every individual as a member of society

Benefits of Health Education:

• Enables a person to remain physically fit and in proper health
• Enhances the health of the community
• Promotes proper utilization of available health resources
• Enables people to make healthier choices and uplift quality of life
• Enhances ability to avoid air, water, and other borne diseases
• Reduces premature deaths
• Decreases financial expenses on treatment
• Enables people to pressure governmental bodies to enhance health services and facilities

Health education plays a vital role in combating water pollution and its health impacts:

• Awareness about contamination sources: Educating communities about how open defecation, improper waste disposal, and industrial effluents pollute water sources
• Household water treatment: Training on boiling, chlorination, filtration (bio-sand/ceramic filters), and SODIS techniques
• Safe water storage: Using covered containers with narrow mouths, not dipping hands in stored water
• Sanitation practices: Proper use and maintenance of toilets, handwashing stations, and drainage
• Environmental protection: Encouraging communities not to dump waste in rivers, protecting water sources from contamination
• Institutional role: School hygiene programs, community health workers (Female Community Health Volunteers in Nepal), mass media campaigns for World Water Day/National Sanitation Week
• Monitoring water quality: Training local users to test water quality using simple kits (H2S vial test for fecal contamination)

In Nepal, organizations like UNICEF, WHO, WaterAid, and the Department of Water Supply and Sewerage (DWSS) actively conduct health education programs. The government's National Hygiene and Sanitation Policy emphasizes health education as a key intervention alongside infrastructure development.

5.5 Organic Pollution 20812073

Organic pollution refers to the contamination of water by organic substances — materials derived from living organisms such as sewage, food waste, animal waste, plant debris, and industrial organic chemicals. Organic pollutants consist of proteins, carbohydrates, fats, and nucleic acid in various combinations. When organic matter enters a water body, microorganisms decompose it, consuming dissolved oxygen (DO) in the process. This oxygen depletion is measured by BOD (Biochemical Oxygen Demand).

5.5.1 Sources & Effects

• Domestic sewage (raw or treated — human excreta, kitchen waste, detergents)
• Industrial effluents (food processing, paper/pulp mills, breweries, tanneries)
• Urban run-off carrying organic debris
• Farm wastes (animal manure, crop residues)
• Organic chemicals
• Food processing waste
• Lubricants (motor oil, Mobil)
• Burning fossil fuels (coal, oil, and gas)

Effects of organic pollution:

• Depletion of dissolved oxygen → fish kills, death of aquatic organisms
• Eutrophication — excessive nutrient loading causes algal blooms
• Foul odor and unsightly appearance
• Spread of waterborne diseases

5.5.2 Aerobic Digestion 2073

Decomposition of organic matter by microorganisms in the presence of oxygen. This is the natural self-purification mechanism of streams and rivers.

• Process: Organic matter + O₂ → CO₂ + H₂O + New Cells + Energy
• Conditions: Requires adequate dissolved oxygen (DO > 2 mg/L), moderate organic load
• End Products: Carbon dioxide, water, stable inorganic compounds (NO₃⁻, PO₄³⁻, SO₄²⁻)
• Characteristics: Odorless, efficient, faster decomposition
• Practical Examples:
  • Activated Sludge Process: Wastewater is aerated in a tank; bacteria decompose organic matter aerobically; used in municipal wastewater treatment plants
  • Trickling Filters: Wastewater trickled over a bed of stones/plastic media; biofilm of microorganisms degrades organic matter
  • Aerated Lagoons: Large ponds with mechanical aerators; used in Hanumanghat and Sallaghari treatment plants in Bhaktapur, Nepal
  • Composting: Solid organic waste decomposed aerobically with turning for aeration

5.5.3 Anaerobic Digestion 2073

Decomposition of organic matter by microorganisms in the absence of oxygen.

• Process: Organic matter → CH₄ (methane) + CO₂ + H₂S + New Cells
• Conditions: No dissolved oxygen; sealed/enclosed environment; pH 6.8–7.4; temperature 30–38°C (mesophilic) or 50–57°C (thermophilic)
• End Products: Biogas (60–70% CH₄, 30–40% CO₂), digestate (nutrient-rich slurry)
• Characteristics: May produce foul odor (H₂S), slower process, but produces useful biogas
• Practical Examples:
  • Biogas Plants: Widely used in rural Nepal; cattle dung and human waste fed into a sealed digester; produces methane for cooking fuel and slurry for fertilizer
  • Septic Tanks: Underground anaerobic treatment of household sewage; solids settle and undergo anaerobic decomposition
  • Stabilization Ponds (anaerobic zone): Deep ponds where bottom layers are anaerobic; used in Dhobighat and Kodku treatment plants in Kathmandu valley
  • Landfill Gas: Organic waste in landfills decomposes anaerobically producing methane

Comparison:

5.5.4 Inorganic Pollutant (Definition) 2081

Inorganic pollutant: A pollutant of mineral origin, not basically of carbon structure. Inorganic pollutants include minerals, metals, and chemical compounds that contaminate the environment.

• Examples: Nitrate (NO₃⁻), fluoride, iron, manganese, arsenic, heavy metals (lead, mercury, cadmium), insecticides, pesticides.

For detailed discussion of each inorganic pollutant and its effects, see Section 5.6.

5.5.5 Mitigative Measures of Indoor Air Pollution (Nepal Context) 2081

Indoor air pollution (IAP) is a critical issue in Nepal, where ~90% of total energy comes from traditional biomass fuels. Indoor pollutant levels can be 2–5 times (sometimes 100+ times) higher than outdoor levels. Key mitigation measures:

1. Improved Cooking Stoves (ICS): Replace traditional open-fire stoves with improved designs that have chimneys and better combustion efficiency — reducing smoke by 50–70%.
2. Biogas as Alternative Fuel: Promote biogas plants (400,000+ installed in Nepal) to replace firewood and dung-cake burning with clean-burning methane gas.
3. Improved Ventilation: Install windows, ventilation holes, and chimneys in kitchens. Traditional houses often lack ventilation in cooking areas.
4. Separate Kitchen Design: Move cooking areas away from living and sleeping spaces to reduce exposure.
5. Alternative Energy Sources: Promote LPG, solar cookers, and electric cooking where grid electricity is available.
6. Health Education: Awareness programs about the health risks of indoor smoke (respiratory diseases, eye problems, lung cancer) and available alternatives.

For full discussion of indoor air pollution causes, health effects, and control strategies, see Section 5.9.

5.6 Inorganic Pollution 2073207120702069

Inorganic water pollution is the contamination of environment caused by inorganic pollutants — pollutants of mineral origin and not of basically carbon structure. The concentration of these pollutants is increasing over the years. Major inorganic pollutants include nitrate, fluoride, iron, manganese, arsenic, heavy metals, insecticides, and pesticides.

5.6.1 Major Inorganic Pollutants

1. Nitrate (NO₃⁻):

• Found in the manufacture of dyes and explosives (e.g., Amatol — a powerful explosive containing TNT)
• Found in medicine used for treating intestinal disorders (bismuth sub nitrate)
• When mixed with phosphates, causes eutrophication — substantial increase in aquatic plants, leading to oxygen depletion
• Health effect: Blue baby syndrome (Methemoglobinemia) in infants | WHO limit: 50 mg/L

2. Fluoride (F⁻):

• Used to purify water, but excessive fluoride can cause bone fracture in adults
• Coal is a major source — extensively seen in countries with coal-burning plants such as China
• Responsible for damaging crops; improper disposal of fluoridated waste may result in leaching
• Dental fluorosis (<1.5 mg/L beneficial); skeletal fluorosis (>4 mg/L) | WHO limit: 1.5 mg/L

3. Iron (Fe):

• Corrosion of water supply iron pipes results in rusty color and metallic taste of water
• Though iron is essential, excessive intake is linked to Alzheimer's, arteriosclerosis, diabetes
• Iron toxicity in water results in death of fish
• Can cause algae blooms, which creates biological oxygen demand | WHO limit: 0.3 mg/L

4. Manganese (Mn):

• Has a tendency to accumulate in organisms and plants — harmful exposures further up the food chain
• Causes adverse health effects: hallucinations, changes in behavior, weakness, speech problems, headaches, tremors, bronchitis, balance problems, and permanent disease like impotence
• Causes discoloration and turbidity in water | WHO limit: 0.1 mg/L

5. Arsenic (As):

• A semi-metallic element, extremely poisonous
• A high-profile problem due to the use of deep tube wells for water supply in the Ganges delta
• A 2007 study showed that over 13.7 crore people in more than 70 countries are affected by arsenic poisoning of drinking water
• Can cause lung cancer, skin cancer, birth defects, and reproductive problems | WHO limit: 0.01 mg/L

6. Heavy Metals (Cu, Cd, Pb, Hg, Se):

• Get mixed in water from industries, automobile exhaust, mines, and even natural soils
• Cadmium found in fertilizer — if consumed can cause diarrhea, and over time liver and kidney damage
• Lead found in lead water pipes — if consumed by children can cause mental retardation
• Mercury: Minamata disease | Chromium: cancer

7. Insecticides:

• Chemical agents used to kill insects in the field
• Organophosphate insecticides include malathion, parathion, and dimethoate
• Types: Broad spectrum, Narrow spectrum, Pheromones, Miticides

8. Pesticides:

• Chemicals used to eliminate or control agricultural pests that damage crops and livestock
• Examples: chlorinated hydrocarbon DDT, chlordane, toxaphene
• Types: Insecticides (kill insects by blocking reproduction/disrupting nervous system), Herbicides (kill weeds), Fungicides (kill fungus), Rodenticides (kill rats and mice)

Effects of Insecticides/Pesticides on Environment:

• Cellular and DNA damage
• Cancers, tumors, and lesions on fish and animals
• Disruption of endocrine system; reproductive inhibition or failure
• Suppression of immune system
• Teratogenic effects (physical deformities such as hooked beaks on birds)
• Poor fish health (low red to white blood cell ratio, excessive slime on scales/gills)
• Intergenerational effects (effects not apparent until subsequent generations)
• Physical effects such as egg shell thinning

5.6.2 Pollution from Sludge & Industrial Waste 20732070

Industrial sludge and waste contain heavy metals (lead, mercury, cadmium, chromium), toxic chemicals, organic compounds, acids, alkalis, oils, and suspended solids. When discharged into water bodies without proper treatment:

• Physical effects: Increased turbidity, temperature changes (thermal pollution), color and odor changes, sedimentation on river/lake beds
• Chemical effects: Heavy metals bioaccumulate in the food chain; toxic chemicals cause long-term health effects; pH changes harm aquatic life
• Biological effects: Oxygen depletion from organic sludge → fish kills; toxic chemicals destroy aquatic ecosystems; eutrophication from nutrient-rich effluents
• Health effects: Contaminated water used for drinking and irrigation causes cancer, neurological diseases, organ damage, and skin diseases

Mitigation Measures:

1. Effluent Treatment Plants (ETP): Mandatory for all industries before discharge — primary (screening, sedimentation), secondary (biological treatment), and tertiary (chemical treatment, filtration)
2. Sludge Treatment: Thickening, digestion (aerobic/anaerobic), dewatering, and safe disposal in engineered landfills
3. Pollution standards enforcement: National effluent discharge standards with regular monitoring and penalties
4. Cleaner production: Waste minimization at source, recycling, reuse of process water
5. Buffer zones: Maintain vegetation buffers along river banks to filter pollutants
6. Environmental Impact Assessment (EIA): Mandatory for new industries near water bodies

Industrial waste and sludge are major sources of water pollution globally and in Nepal. Industries such as carpet factories, tanneries, breweries, distilleries, and brick kilns discharge untreated or partially treated effluents directly into rivers.

Key pollutants: Heavy metals (Pb, Cr, Hg from electroplating and tanning), organic chemicals (dyes, solvents), acids and alkalis, suspended solids, and thermal effluents.

Impacts:

• Bagmati River in Kathmandu receives untreated sewage from over 3 million people and industrial waste — severely polluted with BOD exceeding 200 mg/L in some stretches
• Fish populations have been decimated in urban river stretches
• Groundwater contamination through leaching from industrial dump sites
• Loss of aesthetic and recreational values of water bodies

Mitigation measures: Mandatory ETP installation, enforce Industrial Enterprises Act (1992), Polluter Pays Principle, promote common effluent treatment plants (CETP) for industrial clusters, community-based monitoring of river water quality, strengthening the role of Department of Environment and Nepal Bureau of Standards and Metrology.

5.6.3 Pesticide Hazards in Nepal 2071

Pesticide hazards arise from the use of insecticides, herbicides, and fungicides in agriculture that contaminate water, soil, and food.

• Pesticide use has increased significantly since the 1950s — mainly organochlorines (DDT, BHC), organophosphates, and carbamates
• DDT was widely used for malaria control in the Terai; now banned but residues persist in soil and groundwater
• Indiscriminate use of pesticides in vegetable farming (especially in periurban areas of Kathmandu) — often without following recommended doses or safety periods
• Imported vegetables from India often contain high pesticide residues

Health hazards:

• Acute poisoning: Nausea, vomiting, headache, skin irritation, respiratory problems, and death in severe cases
• Chronic effects: Cancer, endocrine disruption, reproductive problems, neurological damage
• Bioaccumulation: Persistent pesticides like DDT accumulate in the food chain, concentrating in top predators

Water pollution from pesticides: Agricultural runoff carries pesticide residues into rivers, lakes, and groundwater. In Nepal, studies have found pesticide residues in vegetables and water sources in Kathmandu valley, Chitwan, and other intensive farming areas.

Mitigation: Promote Integrated Pest Management (IPM), organic farming, enforce Pesticide Act and Regulations, farmer training on safe handling, provide protective equipment, regulate pesticide imports and sales.

5.6.4 Industrial Wastewater & Treatment 2069

Industrial wastewater is the water discharged from industrial processes that contains pollutants harmful to the environment and human health. The characteristics depend on the type of industry:

• Carpet/textile industry: Dyes, chemicals, high BOD, color
• Tanneries: Chromium, sulfides, high BOD, suspended solids
• Food processing/breweries: High organic load, BOD, fats, oils
• Paper/pulp mills: Lignin, chlorinated compounds, high suspended solids
• Metal industries: Heavy metals (Pb, Zn, Cu, Ni), acids, cyanides

Treatment Methods:

1. Primary Treatment: Physical processes — screening (removing large debris), grit removal, sedimentation (settling of suspended solids), oil and grease removal (skimming)
2. Secondary Treatment: Biological processes — activated sludge, trickling filters, aerated lagoons, rotating biological contactors — to remove dissolved organic matter
3. Tertiary Treatment: Advanced treatment — chemical coagulation/flocculation, activated carbon adsorption, membrane filtration, disinfection (chlorination, UV), nutrient removal (N, P)
4. Sludge Treatment: Thickening, anaerobic digestion, dewatering (filter press, centrifuge), safe disposal

5.6.5 Bagmati River Pollution 2069

1. Direct discharge of untreated municipal sewage from Kathmandu, Lalitpur, and Bhaktapur
2. Industrial effluent discharge without treatment — carpet, dyeing, and food processing industries
3. Solid waste dumping on river banks and into the river
4. Encroachment of river banks by settlements and squatters
5. Non-functional or inadequate wastewater treatment plants (Dhobighat, Kodku, Guheshwori)
6. Religious and cultural activities generating waste at temple areas along the river
7. Rapid urbanization exceeding infrastructure capacity
8. Lack of storm-water drainage separation from sewer lines

5.7 Sources, Causes & Impacts of Air Pollution 207920782077207520732072207120702069

Air pollution is defined as the presence of substances in the atmosphere in quantities and duration that are injurious to human health, property, plant life, animal life, or that unreasonably interfere with the comfortable enjoyment of life.

5.7.1 Sources of Air Pollution 2079207820732070

1. Burning fossil fuels: In industries, coal, oil, and natural gas are burned releasing CO₂, CO, NOₓ, and SO₂ to the atmosphere
2. Motor vehicles: Vehicle use is increasing rapidly — between 1900 and 1970, emissions of nitrogen oxides increased by 690%
3. Incomplete burning of fuel: Releases Volatile Organic Chemicals (VOCs)
4. Garbage: Garbage in landfills emits methane gas; many household products give off VOCs
5. Natural sources: Forest fires emit particulates and VOCs into the atmosphere
6. Ultra-fine dust particles: Dislodged by soil erosion when water and weather loosen layers of soil
7. Radioactive fallout: Yields high amounts of energy plus harmful SO₂ and heavy metals; causes defoliation, deformation, and undergrowth damage in trees
8. Volcanoes: Spew out SO₂ and large amounts of pulverized lava rock (volcanic ash); a big eruption can darken the sky and affect the earth's entire atmosphere
9. Smog: Intense local pollution usually trapped by a thermal inversion; mostly from automobiles or coal
10. Powerlines: High voltage lines near polluted cities attract air with harmful particulates; electricity causes ionization of air; inhaled ionized air increases free radicals → tissue damage, aging, and development of cancer

5.7.2 Causes (Pollutants) 207920782075207320722071

• Particulate Matter (PM₁₀, PM₂.₅): From diesel vehicles, brick kilns, construction dust, biomass burning
• Carbon Monoxide (CO): Incomplete combustion of fossil fuels in vehicles
• Sulfur Dioxide (SO₂): Burning of coal and petroleum containing sulfur; industrial processes
• Nitrogen Oxides (NOₓ): High-temperature combustion in vehicle engines and power plants
• Hydrocarbons (VOCs): Evaporation of fuels, incomplete combustion, industrial solvents
• Lead (Pb): Combustion of leaded gasoline (now largely banned)
• Ozone (O₃): Secondary pollutant formed by reaction of NOₓ and VOCs in sunlight (photochemical smog)

5.7.3 Impacts of Air Pollution 207920782075207320722071

• Health impacts: Respiratory diseases (asthma, bronchitis, emphysema), cardiovascular diseases, lung cancer, eye irritation, headache, premature death (WHO: 2.4 million deaths/year globally)
• Environmental impacts: Acid rain (from SO₂ and NOₓ), ozone layer depletion, global warming, smog, reduced visibility
• Ecological impacts: Damage to vegetation and forests, harm to wildlife, crop yield reduction, soil acidification
• Material damage: Corrosion of buildings, monuments (Taj Mahal), metals, and infrastructure

1. Health Impacts:

• Respiratory diseases — asthma, bronchitis, chronic obstructive pulmonary disease (COPD), lung cancer
• Cardiovascular problems — heart attacks, strokes due to fine particulate matter (PM₂.₅)
• CO poisoning — reduces oxygen-carrying capacity of blood, causes headache, dizziness, death at high levels
• Lead poisoning — brain damage, developmental delays in children
• WHO estimates: 2.4 million premature deaths annually from air pollution
• In Nepal: ARI (Acute Respiratory Infection) accounts for >30% of deaths in children under 5

2. Environmental Impacts:

• Acid rain — oxides of nitrogen and SO₂ in presence of atmospheric moisture turn into droplets of pure acid; attacks limestone, marble, metal; burns leaves of plants and makes lakes too acidic for aquatic life
• Global warming — experts expect a global rise in average temperature of 1.4 to 5.8°C in the next century; warmer temperatures expected to partially melt polar ice caps, raising sea levels
• Ozone depletion — CFCs, nitrous oxide from fertilizers, and methyl bromide attack ozone layer; UV radiation breaks CFCs releasing chlorine; a single chlorine atom can destroy up to 1,00,000 ozone molecules in the stratosphere
• Smog — reduces visibility; ozone in lower atmosphere damages vegetation, kills trees, irritates lung tissues, and attacks rubber

3. Economic Impacts:

• Increased healthcare costs
• Loss of agricultural productivity
• Damage to historical monuments and structures
• Reduced tourism revenue due to poor air quality

5.7.4 Sources of Water Pollution 2070

• Point sources: Industrial effluent outfall pipes, sewage treatment plant discharges, mine drainage
• Non-point sources: Agricultural runoff (fertilizers, pesticides), urban stormwater, atmospheric deposition (acid rain)
• Domestic sewage, solid waste dumping in rivers, religious/cultural waste, hospital waste

5.7.5 Air & Water Pollution in Kathmandu Valley 20782077

• Rapidly increasing vehicular traffic — from 75,159 vehicles (1990) to over 1 million today
• Brick kilns (over 100 around the valley) using coal and biomass
• Road dust and construction activities
• Industrial emissions — 74% of Nepal's industries are classified as air-polluting
• Waste burning (garbage, agricultural residue)
• Valley's bowl-shaped geography traps pollutants (temperature inversion)

Control measures: Use of catalytic converters in vehicles, electronic fuel injection systems, charcoal canisters for evaporative emissions, scrubbers in industrial chimneys, shift to cleaner fuels (natural gas, electric), emission standards enforcement, promoting renewable energy, afforestation, and public awareness.

5.7.6 Acid Rain 2069

Acid rain is the deposition of acidic components (wet and dry) formed when sulfur dioxide (SO₂) and nitrogen oxides (NOₓ) are emitted into the atmosphere and react with water vapor to form sulfuric acid (H₂SO₄) and nitric acid (HNO₃). Normal rain has pH ~5.6; acid rain has pH below 5.0, sometimes as low as 3.0.

Sources: Power plants burning coal (70% of SO₂), motor vehicles (43% of NOₓ), industrial processes (metal smelting, oil refining).

Impacts:

• Aquatic ecosystems: Fish populations decline or die as lake/river pH drops below 5.0; affects entire food chain
• Forests: Slow growth, leaf damage, nutrient leaching from soil; aluminium released from acidified soil damages roots
• Agriculture: Crop damage, reduced yields, soil nutrient depletion
• Buildings & monuments: Corrodes limestone, marble, metal structures; accelerates deterioration
• Groundwater: Acidified water dissolves toxic metals (Pb, Cu) from pipes, contaminating drinking water
• Human health: Respiratory problems from acid aerosols; contaminated drinking water

Control Measures:

• Use low-sulfur fuels and clean-burning alternatives (natural gas)
• Install scrubbers (flue gas desulphurization) in power plant chimneys
• Use catalytic converters in vehicles to reduce NOₓ emissions
• Liming — adding powdered limestone to acidified lakes and soils to neutralize acid
• Emission trading programs (cap-and-trade) for SO₂ and NOₓ
• International agreements and environmental regulations

5.8 Mitigation Measures 2079207820752074207220712070

Air pollution can be mitigated through the following measures:

5.8.1 Vehicular Emission Control 2079207520722071

• Use catalytic converters — reduce CO, HC, and NOₓ by converting them to CO₂, H₂O, and N₂
• Electronic fuel injection systems — ensure proper air-fuel mixing and complete combustion
• Charcoal canister — captures evaporative hydrocarbon emissions from fuel tank
• Mandatory vehicle emission testing and Green Sticker system
• Phase out two-stroke engines and old diesel vehicles
• Promote electric vehicles, CNG vehicles, and public transportation

5.8.2 Industrial Emission Control

• Install scrubbers (flue gas desulphurization) in chimneys to remove SO₂
• Use bag filters, electrostatic precipitators to capture particulate matter
• Use cleaner fuels (natural gas instead of coal)
• Enforce Industrial Enterprises Act (1992) and emission standards

5.8.3 Policy & Planning

• Enforce Nepal Vehicle Mass Emission Standard (2000)
• Environmental Protection Act (1996) enforcement
• Restrict registration of two-stroke engine vehicles in urban and tourist areas
• Urban planning — green belts, traffic management, pedestrian zones

5.8.4 Alternative Energy

• Promote renewable energy: solar, hydro, wind
• Improve energy efficiency in buildings and industries
• Promote improved cook stoves (ICS) in rural areas to reduce indoor smoke

5.8.5 Kathmandu-Specific Measures 207820772074

1. Transport sector: Expand electric bus fleet (Sajha Yatayat model), promote electric two-wheelers, improve road conditions to reduce dust, build cycle lanes and pedestrian paths
2. Brick kilns: Mandatory conversion to zig-zag technology or fixed chimney bull's trench kiln; relocate kilns away from residential areas
3. Road dust: Regular road sweeping and water sprinkling; pave unpaved roads; cover construction sites
4. Waste management: Ban open waste burning; establish proper waste collection and composting/recycling facilities
5. Green infrastructure: Plant trees along roads and in open spaces; protect and expand urban forest patches
6. Monitoring: Expand air quality monitoring network; establish Air Quality Index (AQI) alert system for public awareness
7. Institutional: Strengthen Department of Environment; enforce Environmental Protection Act, Vehicles and Transport Management Act

5.8.6 Water Pollution Mitigation Measures 20782070

Water pollution can be mitigated through the following measures:

1. Wastewater Treatment: Mandatory Effluent Treatment Plants (ETP) for industries — primary (screening, sedimentation), secondary (biological), and tertiary (chemical/filtration) treatment. Common Effluent Treatment Plants (CETP) for industrial clusters.
2. Sewage Management: Construct and maintain functional sewage treatment plants. Separate storm-water drainage from sewer lines. Expand sewer coverage in urban areas.
3. Solid Waste Management: Prevent solid waste dumping in rivers; establish proper collection, composting, and recycling systems. Enforce Solid Waste Management Act (2011).
4. Industrial Regulation: Enforce Industrial Enterprises Act (1992) and national effluent discharge standards. Apply Polluter Pays Principle with monitoring and penalties.
5. Safe Sanitation: Promote on-site sanitation (VIP latrines, pour-flush, septic tanks) and Community-Led Total Sanitation (CLTS) — Nepal achieved ODF status in 2019.
6. Agricultural Runoff Control: Promote Integrated Pest Management (IPM) and organic farming; enforce Pesticide Act; maintain vegetation buffer zones along river banks.
7. Source Protection: Protect water catchment areas, watershed management, rainwater harvesting, and groundwater recharge programs.
8. Institutional Measures: Strengthen the Department of Environment and Nepal Bureau of Standards and Metrology for regular water quality monitoring. Establish central water quality data bank.

Nepal-specific: The Bagmati Civilization Integrated Development Committee (Bagmati Action Plan) coordinates river cleaning in the Kathmandu valley. See Section 5.6.5 for Bagmati-specific causes.

5.9 Indoor Air Pollution 2071

Indoor air pollution (IAP) refers to the pollution in the air of indoor spaces like homes, offices, and buildings. People spend almost 90% of their time at home or offices, making indoor air quality critical. The absence of natural air currents to disperse pollutants results in accumulation at higher concentrations — indoor air levels of many pollutants may be 2–5 times, and occasionally even more than 100 times, the outdoor levels.

5.9.1 Sources of Indoor Air Pollution

• Asbestos insulation, bacteria, molds/mildews
• Animal dander and cat saliva, viruses
• House dust mites, cockroaches, pollen
• Tobacco smoke
• Unvented space heaters, kerosene space heaters
• Wood burning stoves, welding/soldering

5.9.2 Causes (Nepal Context) 2071

1. Biomass fuel combustion: Firewood, agricultural residues (straw, husks), animal dung — the primary source. In Nepal, ~90% of total energy comes from traditional biomass fuels
2. Coal burning: Used for heating in mountain regions
3. Poorly ventilated kitchens: Traditional houses have no chimneys or windows in cooking areas; smoke accumulates indoors
4. Kerosene lamps: Emit particulate matter and CO
5. Tobacco smoke: Indoor smoking contributes to pollutant levels
6. Building materials: Paints, adhesives, insulation may release volatile compounds
7. Incense and candles: Religious practices generate particulate matter

5.9.3 Health Effects

• Acute Respiratory Infection (ARI) — leading cause of death in children under 5 in Nepal (>30% of child deaths)
• Chronic Obstructive Pulmonary Disease (COPD) and chronic bronchitis, especially in women who cook
• Eye irritation, cataracts, blindness
• Lung cancer (2–4 times higher risk in biomass-burning households)
• Low birth weight in babies born to exposed pregnant women
• Mountain populations are more vulnerable due to poorly ventilated houses and cold climate requiring prolonged heating

5.9.4 Control Strategies

a) Source Control: Involves replacing the sources of indoor pollutants — replacement of wood burning stoves by gas or oil-fired furnaces, modification in design of gas/kerosene stoves, proper operation and maintenance of burners.

b) Increased Ventilation: Local and mechanical ventilation increases the rate of air exchange, decreasing pollutant concentrations — installation of hoods over cooking places, ductless cooking ranges with improved carbon filters.

c) Air Cleaning: Adsorbents are used to remove moisture and pollutants from air. Commonly used adsorbents: silica gel, activated alumina, activated carbon, manganese oxides.

5.9.5 Measures for Rural Nepal 2071

1. Improved Cook Stoves (ICS): Efficient stoves with chimneys that vent smoke outside; reduce fuel consumption by 30–50% and smoke by 70–80%
2. Alternative fuels: Promote biogas (gobar gas) — over 400,000 biogas plants installed in Nepal; LPG where accessible; solar cookers in sunny regions
3. Kitchen ventilation: Add windows, eaves spaces, smoke hoods above cooking areas; separate kitchen from living/sleeping areas
4. Behavioral change: Dry fuel wood properly before use (reduces smoke), keep children away from cooking area, avoid burning garbage indoors
5. Electrification: Expand rural electrification through micro-hydro and solar PV for lighting (replace kerosene) and electric cooking
6. Community forestry: Sustainable woodlot management to ensure fuel wood supply while promoting alternatives
7. Health education: Awareness programs on the health risks of indoor smoke, especially targeting women and Female Community Health Volunteers (FCHVs)

5.10 Severity of Its Problems in Nepal 2079

Nepal faces severe water and air pollution problems. Key facts on the severity:

• According to the Environment Pollution Index 2014 published by Yale University, Nepal ranked second from last after Bangladesh in terms of air quality and its effect on human health
• The bowl-shaped topography of the Kathmandu valley causes severe restrictions to the movement of air pollutants (temperature inversion traps pollutants)
• There are above 100 brick kilns in the Kathmandu valley alone (All Brick Kiln Association), operating during dry season releasing high concentration of pollutants
• In 2005, the Ministry of Population and Environment estimated that ambient air pollution was responsible for 1,600 premature deaths in the Kathmandu valley
• A NHRC/WHO study estimated 1,926 cases of premature death per year (NHRC/WHO, 2009) using the Environmental Burden of Disease (EBD) approach
• World Bank estimated Nepal's annual health cost attributed to urban air pollution was USD 21 million in 2007, equivalent to 0.29% of GDP
• WHO guidelines limiting values: TSP: 120 mg/m³, PM₁₀: 70 mg/m³

The government and various agencies have undertaken several efforts:

5.10.1 Legislative Measures 2079

• Environmental Protection Act (1996) & Rules (1997): Mandatory EIA/IEE for development projects
• Water Resources Act (1992) & Regulations (1993): Framework for water resource management and pollution control
• Industrial Enterprises Act (1992): Requires pollution control measures for industries
• Vehicles and Transport Management Act (1993): Emission standards for vehicles
• Nepal Vehicle Mass Emission Standard (2000): Regulates vehicular emissions
• Solid Waste Management Act (2011): Updated framework for waste management
• Nepal Petroleum Products Act (1993): Fuel quality regulation

5.10.2 Institutional Measures

• Establishment of the Ministry of Forests and Environment
• Department of Environment — monitoring and enforcement
• Nepal Bureau of Standards and Metrology — setting environmental standards
• Department of Water Supply and Sewerage — water supply and sanitation

5.10.3 Programmatic Measures

• Restriction on registration of two-stroke engine vehicles in major urban and tourist towns
• Ban on leaded gasoline
• Promotion of electric vehicles (Safa Tempo program — electric three-wheelers in Kathmandu)
• Bagmati Civilization Integrated Development Committee (Bagmati Action Plan) for river cleaning
• Community-Led Total Sanitation (CLTS) — Nepal declared national ODF status in 2019
• National Biogas Program — over 400,000 plants installed to reduce indoor air pollution
• Improved Cook Stove (ICS) programs in rural areas
• Ratification of Montreal Protocol (1996) — phasing out ODS by 2010

Challenges:

• Inadequate monitoring and weak enforcement of existing laws
• Lack of water quality standards and systematic data collection
• Non-functional wastewater treatment plants
• Rapid urbanization outpacing infrastructure development
• Insufficient budget and technical manpower for environmental management
• No central data bank on water or air quality

Quick-Revision Summary

Chapter 5 — Water & Air Pollution — 34 past exam questions

Key Points to Remember

1. F-Diagram: Feces → Fluids/Fields/Flies/Fingers/Food → New Host
2. BOD = Biochemical Oxygen Demand; measures organic pollution strength
3. 10 air pollution sources: fossil fuels, vehicles, combustion, garbage, natural, dust, radioactive, volcanoes, smog, powerlines
4. Key pollutants: PM₂.₅, CO, SO₂, NOₓ, VOCs, Lead, O₃
5. KTM valley: bowl-shaped geography traps pollutants; 100+ brick kilns; 1 million+ vehicles
6. Nepal: 2nd worst air quality (Yale 2014); ~90% energy from biomass; ODF status 2019