GROUP B - SAQ (10 MARKS EACH)

Q1. Household Water Purification - Four Methods, Advantages & Disadvantages (2+8=10)

Four Methods of Household Water Purification

1. Boiling
2. Chemical disinfection (chlorination, iodine)
3. Filtration (ceramic/candle filters)
4. Ultraviolet (UV) irradiation
5. (Also acceptable: Multi-stage Reverse Osmosis)

Detailed Description of Any Two Methods

(A) BOILING

• Kills all bacteria, spores, cysts, and ova - yields truly sterilized water
• Removes temporary hardness by driving off CO2 and precipitating calcium carbonate
• No special equipment or chemicals required
• Reliable and universally applicable

• Offers no residual protection against subsequent microbial contamination
• Alters taste (though harmless)
• Requires fuel - costly and adds to indoor air pollution
• Does not remove chemical contaminants (e.g., fluoride, arsenic)
• Impractical at community scale

(B) CHEMICAL DISINFECTION (Chlorination)

• Bleaching powder (CaOCl2): contains ~33% available chlorine; unstable on exposure to air/light
• Chlorine solution: 4 kg bleaching powder in 20 litres = 5% chlorine solution
• High Test Hypochlorite (HTH/Perchloron): 60-70% available chlorine; more stable
• Chlorine tablets (e.g., Halazone): 1 tablet of 0.5g disinfects 20 litres
• Iodine: 2 drops of 2% ethanolic iodine per litre; contact time 20-30 minutes

• Cheap, easy to apply at household level
• Provides residual protection against recontamination during storage and distribution
• Effective against most pathogens
• Easy to test using orthotoluidine test

• Ineffective against spores, protozoal cysts, helminthic ova, and certain viruses (polio, hepatitis) at standard doses
• Requires water to be clear and free from turbidity for efficient action
• Imparts taste and odour (chlorinous smell)
• Bleaching powder is unstable - loses potency on prolonged storage
• Iodine affects thyroid function with prolonged use

(C) FILTRATION (Ceramic/Candle Filters)

• Removes bacteria effectively; Katadyn filter has added oligodynamic action of silver
• No chemical addition
• Portable and usable at household level

• Does NOT remove viruses (filter-passing viruses pass through)
• Candles get clogged with impurities; must be cleaned by scrubbing under running water and boiled at least once a week
• Only suitable for clear (not turbid) water
• Not suitable for widespread use under Indian field conditions

(D) ULTRAVIOLET (UV) IRRADIATION

• Effective against bacteria, viruses, fungi, algae, protozoa, and yeast
• No foreign matter introduced; no taste or odour produced
• Short exposure period; overexposure not harmful

• No residual protection against subsequent contamination
• Water must be turbidity-free (turbid water reduces UV penetration)
• No simple rapid field test to assess treatment efficiency
• Equipment is expensive

Q2 & Q3. Fluorosis - Diagnosis, Clinical Features, Control (2+5+3=10)

Diagnosis

• At ~1 ppm: very mild mottling in 10% of children
• At 4-6 ppm: incidence approaches 100%, with marked increase in severity
• At 4 mg/L sustained: deficits in cortical bone mass and increased bone loss over time

Dental Fluorosis (Mottled Enamel)

• Small, opaque, paper-white areas scattered irregularly over tooth surface (early/mild)
• Discrete or confluent, deep brown-to-black-stained pits giving the tooth a corroded appearance (severe)
• Results from partial failure of enamel-forming ameloblasts
• Mottling is one of the first visible signs of excess fluoride intake during childhood
• Affects only developing permanent teeth (fluoride ingestion during tooth development)

Progressive Skeletal and Extra-skeletal Manifestations of Chronic Fluorosis

A. SKELETAL MANIFESTATIONS (Skeletal Fluorosis)

• Osteosclerosis: Increased bone density due to (i) elevated osteoblastic activity and (ii) replacement of hydroxyapatite by the denser fluorapatite
• Spinal column involvement: stiffness, backache, limitation of spinal movements
• Genu valgum (knock-knee) - especially in children

• Marked cortical thickening of long bones
• Numerous exostoses (bony outgrowths) scattered throughout the skeleton
• Calcification of ligaments, tendons, and muscle attachments
• Kyphosis, scoliosis
• Neurological complications due to spinal cord/nerve root compression: radiculopathy, myelopathy, paraplegia
• Disabling and crippling disease in its severest form

B. EXTRA-SKELETAL / NON-SKELETAL MANIFESTATIONS

• GI system: Nausea, vomiting, abdominal pain, constipation/diarrhea (chronic exposure)
• Neurological: Neuromuscular weakness, cognitive impairment (especially in children), headache, fatigue
• Renal: Polyuria, albuminuria (renal tubular damage with high fluoride levels)
• Reproductive: Reduced fertility (animal studies; evidence in humans is accumulating)
• Thyroid: Fluoride may inhibit thyroid function leading to hypothyroidism
• Cardiovascular: Elevated blood pressure, cardiac anomalies reported in high-endemic areas
• Metabolic: Hypocalcemia due to fluoride binding calcium (in acute high-dose exposure)

Control of Endemic Fluorosis at Community/Population Scale

1. Defluoridation of Drinking Water (most important)

• Nalgonda technique (developed in India by NEERI, Nagpur): Addition of alum (aluminium sulphate) and lime to water, followed by flocculation, sedimentation, and filtration. Reduces fluoride to safe levels (<1 mg/L). Can be used at household and community level.
• Activated alumina/activated charcoal adsorption: Used in treatment plants
• Reverse osmosis: Effective at household level; expensive
• Ion exchange: Removes fluoride ions
• Bone char/contact precipitation

2. Alternative Water Sources

• Shift to safe surface water sources or deep (confined) aquifers with acceptable fluoride levels
• Piped water supply from safe sources
• Rainwater harvesting

3. Nutritional Measures

• Adequate calcium and vitamin C intake reduces fluoride absorption and mitigates effects
• Adequate protein and antioxidants help

4. Surveillance and Screening

• Mapping of fluoride-affected areas; regular water quality monitoring
• Periodic school dental health surveys

5. Health Education

• Educate communities about danger signs, dietary measures, and the need to use safe water sources

Q4. Waterborne Diseases, Well Disinfection, BOD, Rainwater Harvesting (2+4+2+2=10)

Classification of Waterborne Diseases

• Bacterial: Cholera (Vibrio cholerae), typhoid (Salmonella typhi), paratyphoid, bacillary dysentery (Shigella), E. coli diarrhea, leptospirosis
• Viral: Infectious hepatitis A & E, poliomyelitis
• Protozoal: Amoebic dysentery (E. histolytica), giardiasis, cryptosporidiosis
• Helminthic: Ascariasis, guinea worm (dracunculiasis)

Steps of Disinfection of a Well

1. Calculate the volume of water in the well: Volume (litres) = (3.14 × d² × h)/4 × 1000 (where d = diameter in metres, h = depth of water column in metres)
2. Estimate chlorine demand using Horrocks' apparatus to determine the amount of bleaching powder required. Roughly 2.5 g of good bleaching powder disinfects 1,000 litres.
3. Prepare bleaching powder solution: Place calculated amount of bleaching powder in a bucket (not more than 100g per bucket), make a thin paste, add water to 3/4 full, stir, allow lime to sediment for 5-10 minutes. Transfer only the supernatant (discard lime sediment - adding lime increases water hardness).
4. Mix the solution into the well: Lower the bucket containing chlorine solution below the water surface; agitate well water vigorously both vertically and laterally several times for uniform mixing.
5. Contact period: Allow exactly 1 hour contact before drawing water for use.
6. Test for residual chlorine using the orthotoluidine arsenite (OTA) test. If free residual chlorine is less than 0.5 mg/litre at the end of 1 hour, repeat the chlorination procedure. Wells should be disinfected every day during cholera epidemics.

Biological Oxygen Demand (BOD)

• It is a measure of the organic pollution of water.
• High BOD = heavy organic pollution (sewage, industrial effluent)
• Standard BOD of clean, unpolluted river water: < 1 mg/L
• BOD of raw sewage: 200-400 mg/L
• Significance: High BOD depletes dissolved oxygen in water, killing aquatic life; used to assess the self-purification capacity of rivers and to evaluate effectiveness of sewage treatment plants.

Rainwater Harvesting

• Roof catchment systems: Rain falling on the roof is channelled via gutters and downpipes into storage tanks (ferro-cement tanks, underground cisterns). Most common for household use.
• Surface runoff harvesting: Directing surface runoff from land into ponds, check dams, or percolation tanks; also used for groundwater recharge.
• In-situ harvesting: Contour bunds, terracing, farm ponds to trap rain where it falls (used in agriculture).

• Provides safe drinking water in areas where groundwater is contaminated (e.g., with fluoride, arsenic)
• Reduces dependence on depleted aquifers
• Recharges groundwater; reduces flooding
• Low-cost, community-managed solution
• Quality: Rainwater is initially relatively pure but may be contaminated by roof materials, bird droppings, or atmospheric pollutants - must be filtered and disinfected before use

Q5 & Q8 & Q9. Safe & Wholesome Water + Water Related Diseases + Chlorination Principles (2+3+3+2 / 2+4+4 / 2+4+4=10)

Definition of Safe and Wholesome Water

WHO Quality Standards for Drinking Water

A. Physical Parameters

B. Chemical Parameters (Selected)

C. Bacteriological Parameters

• Total coliforms: 0 per 100 mL in treated piped water
• E. coli / thermotolerant coliforms: 0 per 100 mL (must not be detectable in any 100 mL sample)
• Residual free chlorine: 0.2-0.5 mg/L at consumer's tap

Principles of Chlorination

1. The water must be clear and free from turbidity: Turbid water impedes efficient chlorination - particles shield organisms from chlorine action. Pre-treat with sedimentation/filtration if turbid.
2. Chlorine demand must be estimated: The chlorine demand is the difference between chlorine added and residual chlorine at end of 60 minutes contact. This equals the amount consumed destroying bacteria and oxidizing organic/ammoniacal matter. The "break-point" is when this demand is fully met.
3. Adequate contact period: Free residual chlorine must be present for at least 1 hour contact to kill bacteria and viruses. (Note: chlorine has no effect on spores, protozoal cysts, and helminthic ova except in higher doses.)
4. Free residual chlorine: Minimum 0.5 mg/L free residual chlorine after 1 hour contact. This also provides a safety margin against subsequent recontamination during storage and distribution.
5. Correct total dose: Total chlorine dose = Chlorine demand of the specific water + 0.5 mg/L (required free residual)

• H₂O + Cl₂ → HCl + HOCl (hypochlorous acid)
• HOCl → H⁺ + OCl⁻ (hypochlorite ion)
• Disinfection is mainly due to hypochlorous acid (HOCl) - 70-80 times more effective than hypochlorite ion
• Works best at pH 7 (predominance of HOCl)
• Unreliable above pH 8.5 (HOCl ionizes to OCl⁻)

Q6. Bacteriological Tests for Surveillance of Drinking Water (2+8=10)

Definition of Safe and Wholesome Water

Bacteriological Tests for Drinking Water Surveillance

Why Coliforms?

• Easy to detect and enumerate
• Present in far greater numbers than pathogens
• More resistant to disinfection than most pathogens (conservative indicator)

Tests

1. Multiple Tube Fermentation (MTF) / Most Probable Number (MPN) Method

• Serial dilutions of water inoculated into tubes of MacConkey broth (lactose peptone water with Durham tube)
• Incubated at 37°C for 24-48 hours
• Positive: production of acid + gas (CO₂) from lactose fermentation
• Presumptively positive for coliforms

• Positive tubes sub-cultured into brilliant green bile broth (for total coliforms)
• Incubated at 44°C (for thermotolerant/fecal coliforms - mainly E. coli)
• Acid and gas production confirms fecal coliform presence

• Isolation on Eosin Methylene Blue (EMB) agar; typical metallic green sheen colonies indicate E. coli
• Gram stain, biochemical tests (IMViC) confirm E. coli

2. Membrane Filtration Technique (MFT)

• A measured volume of water (usually 100 mL) is passed through a cellulose nitrate membrane filter (pore size 0.45 μm) that retains all bacteria
• The membrane is placed on selective media (e.g., Endo agar, m-Endo medium)
• After incubation at 37°C (total coliforms) or 44°C (fecal coliforms), colonies are counted
• Results expressed as colonies per 100 mL
• Advantages: Rapid, more accurate, handles larger volumes, gives direct colony count
• Disadvantages: Cannot be used on turbid water (filter clogs); requires special membrane filters and vacuum equipment

3. Presence-Absence (P-A) Test

• Simplified test for routine surveillance of treated water supplies
• A single large volume (100 mL) of water added to a single bottle of medium
• Any coliform growth = fail; no growth = pass
• Cheaper, easier - suitable for rapid field use

4. H₂S Strip Test

• Simple, inexpensive field test
• A filter paper impregnated with sodium thiosulphate and ferric ammonium citrate is placed in a water sample
• H₂S-producing bacteria (indicator of fecal contamination) turn the strip black
• Used widely in rural India for rapid field screening

Interpretation (WHO/BIS Standards):

• Piped treated water: Total coliforms = 0/100 mL; E. coli = 0/100 mL
• Untreated groundwater/borewell: E. coli = 0/100 mL (should not be detectable)

Q7. Purification of Water at Large Scale (2+8=10)

Steps of Water Purification at Large Scale (Water Treatment Plant)

1. Collection / Intake

2. Pre-treatment / Screening

• Coarse screens (bar screens) and fine screens remove large debris, leaves, and suspended particles
• Pre-chlorination may be done at this stage to control algae and reduce taste/odour

3. Storage / Plain Sedimentation

4. Coagulation and Flocculation

• Coagulants like alum (aluminium sulphate) added at dose of 30-40 mg/L (adjusted by jar test)
• Alum forms a gelatinous precipitate (floc) of Al(OH)₃ which adsorbs colloidal particles, bacteria, and organic matter
• Assisted by slow stirring (flocculation) to aggregate fine particles into larger settleable masses
• Removes residual turbidity, colour, and micro-organisms

5. Sedimentation (Clarification)

• Water passed slowly through large sedimentation tanks; floc settles to the bottom (sludge)
• Reduces turbidity from ~25 NTU to ~5 NTU
• Residence time: 2-4 hours

6. Filtration

• Rate: 2-3 m.g.a.d (million gallons per acre per day)
• Sand grain size: 0.2-0.3 mm; depth 60-90 cm on gravel bed
• A biologically active "Schmutzdecke" (zoogloeal layer) forms on top - mainly responsible for purification
• Removes bacteria by 99.9-99.99%
• Cleaned by scraping and replacing top layer of sand
• Requires large land area

• Rate: ~200 m.g.a.d
• Sand grain size: 0.4-0.7 mm
• Requires chemical coagulation beforehand
• Cleaned by backwashing
• Removes bacteria 98-99%
• Requires less space

7. Disinfection (Chlorination)

• Chlorine gas (first choice - cheap, efficient), chloramine, or perchloron
• Paterson's Chloronome used for measuring and applying gaseous chlorine
• Goal: free residual chlorine of 0.2-0.5 mg/L at consumer's tap (after distribution losses)
• Applied after filtration (clear water)

8. Fluoridation / Defluoridation / pH Adjustment

• Where fluoride <0.6 mg/L, fluoride may be added (up to 1 mg/L) to prevent dental caries
• Where fluoride is excessive, defluoridation by Nalgonda technique
• pH adjustment if needed

9. Distribution

Q10. Waterborne Diseases + Principles of Chlorination (5+5=10)

Q11. Health Effects of Noise Exposure + Control of Noise Pollution (5+5=10)

Major Health Effects of Noise Exposure

A. Auditory Effects

1. Temporary Threshold Shift (TTS): Temporary reduction in hearing sensitivity following acute noise exposure; recovers with rest. Repeated TTS can progress to permanent damage.
2. Permanent Threshold Shift (PTS) / Noise-Induced Hearing Loss (NIHL): Irreversible sensorineural hearing loss due to destruction of hair cells in the organ of Corti.
   • Begins at 4000 Hz frequency (notch at 4 kHz on audiogram)
   • Gradually extends to speech frequencies (500-2000 Hz) causing functional deafness
   • NIHL is the most common occupational disease worldwide
3. Acoustic Trauma: Sudden, irreversible hearing damage from a single explosive noise (blast injury)
4. Tinnitus: Persistent ringing/buzzing in the ears, often associated with NIHL

B. Non-Auditory / Extra-Auditory Effects

1. Cardiovascular effects: Hypertension; increased heart rate; vasoconstriction; increased risk of ischemic heart disease; elevated serum cholesterol and adrenaline levels. Chronic noise raises systolic/diastolic BP.
2. Psychological effects: Annoyance, irritability, stress, anxiety, depression, reduced concentration, cognitive impairment (especially in children - impacts learning and academic performance)
3. Sleep disturbance: Noise at night (>45 dB) disrupts sleep cycles; causes fatigue, poor daytime performance, immune suppression
4. Neuroendocrine effects: Activation of the sympatho-adrenal axis and hypothalamo-pituitary-adrenal axis; elevated cortisol, adrenaline, noradrenaline
5. Reproductive effects: Increased rates of low birth weight and preterm birth in women chronically exposed to high noise levels during pregnancy
6. Gastrointestinal effects: Peptic ulcers, dyspepsia (mediated via stress hormones)
7. Performance and productivity: Reduced work efficiency; increased errors and accidents (noise masks warning signals)

• Residential areas: 55 dB(A) day; 45 dB(A) night
• Hospitals, schools: 35-40 dB(A)
• Industrial workplace: 85-90 dB(A) (8-hour TWA)

Control of Noise Pollution

A. INDIVIDUAL LEVEL

1. Personal Protective Equipment (PPE):
   • Ear muffs: reduce noise by 20-40 dB; cover the entire pinna; for very high noise
   • Ear plugs (cotton wool, foam, pre-formed rubber): reduce noise by 10-15 dB; inserted into ear canal
   • Canal caps: semi-insert protectors
2. Time limitation: Limit duration of exposure to high-noise environments (use work-rest cycles); no worker should be exposed to >85 dB for >8 hours/day
3. Behavioral: Avoid personal audio devices at high volumes; use quiet settings on appliances; choose quieter housing locations

B. COMMUNITY LEVEL

1. Engineering controls (at source):
   • Substitution of noisy machinery with quieter alternatives
   • Vibration damping and isolation; anti-vibration mounts
   • Enclosure of noisy equipment; acoustic shields/barriers
   • Maintenance of machinery to prevent excessive noise from wear
   • Mufflers/silencers on exhaust systems
2. Control in the transmission path:
   • Sound-absorbing panels and acoustic tiles in buildings
   • Green belts/tree belts along highways and industrial zones (trees reduce noise by 5-10 dB per 30m)
   • Earth berms, noise barriers/walls along highways
   • Building design (double-glazed windows, insulation)
   • Routing of heavy traffic away from residential areas
3. Town planning measures:
   • Zoning: separation of industrial, commercial, and residential zones
   • Land-use planning to keep noise-sensitive buildings (hospitals, schools) away from traffic/industry
   • Airports sited away from residential areas; flight path restrictions (night curfews)

C. POLICY / LEGISLATIVE LEVEL

1. Legislation and standards:
   • Environment (Protection) Act 1986 (India) - empowers government to set noise standards
   • Noise Pollution (Regulation and Control) Rules 2000 (India): sets ambient noise standards for industrial, commercial, residential, and silence zones
   • The Factories Act - regulates occupational noise exposure
   • Motor Vehicles Act - vehicle noise limits
2. Enforcement and monitoring:
   • Regular noise monitoring in workplaces (audiometry programs for workers)
   • Fines and penalties for violations
   • Vehicle fitness certificates linked to noise compliance
3. Public awareness and education:
   • Health education campaigns on dangers of noise
   • Restrictions on use of loudspeakers, firecrackers (especially near hospitals/schools)
   • Promotion of quiet technologies
4. International regulations: WHO Night Noise Guidelines; EU Environmental Noise Directive

GROUP C - SHORT NOTES (5 MARKS EACH)

1. Concept of Primary Health Care [JNM]

• Arose from failure of existing health services (hospital/specialist-centred, inequitable) to reach the masses
• International Joint WHO-UNICEF Conference at Alma-Ata, USSR, 1978; attended by 134 governments
• Goal: Health for All by the Year 2000 A.D. (HFA 2000)
• Accepted the principle: "The existing gross inequality in health status of people is politically, socially and economically unacceptable"

1. Education about prevailing health problems and methods of preventing and controlling them
2. Safe water supply and basic sanitation
3. Child and maternal health care including family planning
4. Appropriate treatment of common diseases and injuries
5. Prevention and control of endemic diseases
6. Immunization against major infectious diseases
7. Supply of essential drugs
8. Maintenance of food supply and proper nutrition

1. Social equity - equitable distribution of health care
2. Nation-wide coverage - universal access regardless of geography/economic status
3. Self-reliance - people are active participants, not passive recipients
4. Intersectoral coordination - health depends on sectors beyond health (agriculture, education, water, housing)
5. People's involvement - planning and implementation with community participation

• First level of contact between individuals, family, and community with the national health system
• Integrates promotive, preventive, curative, and rehabilitative services
• Involves a new cadre of health workers (community health workers, ASHA, anganwadi workers, multipurpose workers)
• Part of the country's overall socio-economic development plan
• "Health by the people" / "Health in people's hands"

2. Microbiological Indicators of Water Pollution [MsdMCH]

Characteristics of an Ideal Indicator Organism

1. Be present whenever the pathogen of concern is present
2. Be present in larger numbers than the pathogen (easy to detect)
3. Be at least as resistant to disinfection as the pathogen (or more resistant)
4. Not multiply in the water environment
5. Be easy, rapid, and inexpensive to detect and enumerate
6. Be absent from unpolluted water
7. Be harmless to the tester

Indicators Used

(A) Coliform Group (Most Important)

(B) Fecal Streptococci (Enterococci)

• Streptococcus faecalis, S. bovis, S. equinus
• More resistant to environment and disinfection than coliforms
• Useful when coliforms are absent but fecal contamination is still suspected
• FC:FS ratio (Fecal Coliform:Fecal Streptococcus ratio):
  • Ratio >4: contamination of human fecal origin
  • Ratio <0.7: contamination of animal fecal origin
  • Ratio 0.7-4: mixed origin

(C) Clostridium perfringens

• Anaerobic spore-forming organism found in human feces
• Spores are highly resistant to disinfection
• Its presence (even when coliforms are absent) indicates historical or remote fecal contamination
• Useful to detect intermittent or past contamination events

(D) Bacteriophages (Coliphages)

• Viruses that infect E. coli
• Used as indicators of viral contamination (surrogates for human enteric viruses like poliovirus, norovirus)
• More resistant to disinfection than bacterial coliforms; better correlate with enteric virus behavior

(E) H₂S-Producing Bacteria

• A simple, inexpensive field indicator
• Detection by H₂S strip test (paper impregnated with sodium thiosulphate + ferric ammonium citrate)
• Blackening = presence of H₂S-producers, suggesting fecal pollution
• Used widely in resource-limited settings and rural India

Microbiological Standards (WHO/BIS)

3. Sources and Consequences of Indoor Air Pollution in Rural India [RGK]

Definition

Sources of Indoor Air Pollution in Rural India

1. Biomass Combustion (Primary Source)

• Cooking fuels: Firewood (wood), agricultural crop residues (straw, stalks), animal dung (cowdung cakes), charcoal
• Used in poorly ventilated kitchens and open chulhas (cookstoves) in ~70% of rural Indian households (as per NSSO data)
• Produces: carbon monoxide (CO), particulate matter (PM2.5, PM10), nitrogen oxides (NOx), sulphur dioxide (SO₂), polycyclic aromatic hydrocarbons (PAHs), benzene, formaldehyde, and acrolein
• Women and children most affected (spend most time near cooking area)

2. Kerosene Combustion

• Kerosene lamps (lanterns), kerosene stoves
• Produces CO, soot, SO₂, and volatile organic compounds (VOCs)
• Poor-quality wick lamps generate high particulate emissions

3. Tobacco Smoke

• Environmental tobacco smoke (ETS) / second-hand smoke from cigarettes, bidis, hookahs
• Contains >4,000 chemical compounds; 70+ known carcinogens
• Important source of indoor pollution in homes where members smoke

4. Building Materials

• Asbestos in old roofing sheets: fibres become airborne during disturbance - causes mesothelioma, asbestosis
• Formaldehyde from plywood, chipboard, adhesives
• Radon gas seeping from soil/granite rocks through floor cracks (radioactive; lung carcinogen)

5. Biological Sources

• Mold, mildew, fungi on walls (damp housing) - spores cause allergic diseases
• Dust mites, cockroach allergens (important triggers for asthma)
• Rodent and animal dander
• Bacteria and viruses from overcrowding

6. Pesticides and Agricultural Chemicals

• Storage of pesticides indoors; fumigation for stored grain - organophosphates, DDT, BHC
• Vapours from these chemicals contaminate indoor air

7. Incense Burning / Dhoop / Agarbatti

• Religious burning of incense - releases fine particulate matter and VOCs
• Chronic exposure associated with increased respiratory symptoms

Health Consequences of Indoor Air Pollution

Respiratory Effects (Most Significant)

1. Acute Lower Respiratory Infections (ALRI) / Pneumonia in children: The single most important mortality consequence of IAP; responsible for ~1.6 million child deaths/year globally. Fine particulates impair mucociliary clearance and alveolar macrophage function.
2. Chronic Obstructive Pulmonary Disease (COPD): Biomass smoke is a leading cause of COPD in non-smoking women in rural India ("biomass COPD"). Chronic cough, progressive dyspnoea.
3. Asthma: Both initial sensitization and exacerbations triggered by biomass smoke, allergens (dust mites, mold), and ETS
4. Lung Cancer: Long-term exposure to PAHs (from biomass/coal combustion) and radon gas increases lung cancer risk. Coal smoke classified as Group 1 carcinogen (IARC).
5. Nasopharyngeal and laryngeal cancers: Associated with biomass smoke exposure

Cardiovascular Effects

• Fine PM2.5 enters systemic circulation → endothelial dysfunction, atherosclerosis, thrombosis
• Increased risk of ischemic heart disease, stroke (especially with coal/biomass smoke)
• CO from biomass combustion causes chronic low-level CO poisoning: headache, fatigue, impaired cognition, reduced oxygen-carrying capacity

Ocular Effects

• Conjunctivitis, irritation - from smoke and particulates
• Possible increased risk of cataracts (biomass smoke) - PAHs implicated

Pregnancy and Neonatal Outcomes

• Low birth weight, intrauterine growth retardation
• Increased stillbirth and perinatal mortality in women exposed to high IAP

Neurological Effects

• CO poisoning: chronic low-level exposure causes headache, dizziness, and cognitive impairment in children
• Adverse effects on neurodevelopment in children

Control of Indoor Air Pollution in Rural India

1. Improved Cookstoves (ICS): The Pradhan Mantri Ujjwala Yojana (PMUY) promotes LPG use; MNRE promotes biomass gasifier and improved chulhas that reduce smoke by 50-90%
2. LPG and clean fuels (LPG, biogas, solar cookers) to replace biomass - national priority
3. Better housing design: Proper chimneys, exhaust vents, windows for cross-ventilation
4. Tobacco control policies: Smoking bans indoors; Cigarettes and Other Tobacco Products Act (COTPA)
5. Health education: Awareness of dangers of biomass burning; promotion of clean fuel adoption
6. Radon mitigation: Sealing floor cracks, sub-slab depressurization