Air Pollution & Lung Impact - Smoggy Sicknesses
- Key Air Pollutants & Sources:
- Gases: Sulfur dioxide ($SO_2$), Carbon monoxide ($CO$), Nitrogen dioxide ($NO_2$), Ozone ($O_3$).
- Particulate Matter (PM): $PM_{2.5}$ (fine, deep lung penetration) & $PM_{10}$ (coarse).
- Indoor Pollutants: Tobacco smoke (active/passive), Radon (radioactive gas from soil, ↑ lung cancer risk), Formaldehyde (building materials, irritant).
- Respiratory System Impacts:
- Inflammation & Irritation: Acute tracheitis, bronchitis.
- Exacerbation of pre-existing conditions: Asthma, COPD.
- Chronic Effects: ↓ Lung function, chronic bronchitis.
- Carcinogenesis: Lung cancer (tobacco smoke, radon, $PM_{2.5}$). Mechanisms include oxidative stress and direct DNA damage.
⭐ $PM_{2.5}$ (particles < 2.5 micrometers) are major contributors to lung disease due to their ability to penetrate deeply into alveoli and even enter systemic circulation, causing inflammation and cardiovascular effects beyond the lungs. Tobacco smoke is a potent mix of carcinogens and irritants, significantly increasing lung cancer risk.
Pneumoconioses - Dusty Lung Diseases
Occupational lung diseases caused by inhalation of mineral dusts, leading to fibrosis.
| Disease | Agent | Occupation | Key Pathology | Complications |
|---|---|---|---|---|
| Silicosis | Silica | Mining, sandblasting, stone cutting | Silicotic nodules (upper lobes), eggshell calcification | Progressive Massive Fibrosis (PMF), ↑ TB risk, Caplan syndrome |
| Asbestosis | Asbestos fibers | Shipbuilding, insulation, construction | Asbestos bodies, diffuse interstitial fibrosis (lower lobes), pleural plaques | Lung cancer (bronchogenic carcinoma > mesothelioma), Mesothelioma, Caplan syndrome |
| Coal Worker's Pneumoconiosis (CWP) | Coal dust | Coal mining | Coal macules/nodules (upper lobes) | PMF, Caplan syndrome |
| Berylliosis | Beryllium | Aerospace, electronics, nuclear industry | Non-caseating granulomas (similar to sarcoidosis) | Chronic beryllium disease, ↑ lung cancer risk |
📌 Silicosis: Sandblasting, Stone cutting, Superior (upper) lobes, ↑ TB Susceptibility.
Heavy Metal Poisoning - Toxic Metal Menace
| Metal | Sources/Abs. | Clinical/Patho | Diagnosis |
|---|---|---|---|
| Pb | Paint, pipes (ingest/inhale) | CNS (↓IQ child), PNS (wrist drop), GI colic, Burton's line; Basophilic stippling, renal inclusions | BLL (>5 µg/dL child, >10 adult) |
| Hg | Dental amalgam, fish (ingest), vapor (inhale) | Tremors, erethism, Minamata, Acrodynia; ATN, neuronal damage | Blood/urine Hg |
| As | Pesticides, water (ingest/inhale) | Acute (GI, garlic breath); Chronic (skin, Mee's lines, cancers); Mito/capillary damage | Urine As; Hair/nail (chronic) |
| Cd | Batteries, smoking (inhale/ingest) | Kidney (tubular damage), Lungs (emphysema), Bones (Itai-Itai); Renal tubular necrosis | Urine Cd, ↑β2-microglobulin |
Chemical & Radiation Hazards - Potent Polluters
- Pesticides:
- Organophosphates/Carbamates: Cholinesterase inhibition → SLUDGE syndrome (📌 Salivation, Lacrimation, Urination, Defecation, GI distress, Emesis).
- Organochlorines (DDT): Neurotoxicity, endocrine disruption.
- Industrial Chemicals:
- Vinyl chloride → Angiosarcoma (liver).
- Benzene → Leukemia (AML).
- Aromatic amines → Bladder cancer.
- Radiation Hazards:
- Ionizing Radiation: DNA damage (direct/indirect). Units: Gray ($Gy$) absorbed dose, Sievert ($Sv$) equivalent dose.
- Stochastic effects: Cancer risk ↑ with dose (no threshold).
- Deterministic effects: Severity ↑ with dose (threshold exists, e.g., >2 $Gy$ for hematopoietic syndrome).
- Highly sensitive tissues: Lymphoid, hematopoietic, gonads.
- UV Radiation (Sunlight): Pyrimidine dimers in DNA → Skin cancers (melanoma, SCC, BCC).
- Ionizing Radiation: DNA damage (direct/indirect). Units: Gray ($Gy$) absorbed dose, Sievert ($Sv$) equivalent dose.
⭐ Benzene exposure is a significant risk factor for developing Acute Myeloid Leukemia (AML).
High‑Yield Points - ⚡ Biggest Takeaways
- Lead poisoning: Basophilic stippling, wrist/foot drop, neurotoxicity in children, Burton's line.
- Mercury poisoning: Minamata disease (organic), CNS/kidney damage (inorganic).
- Arsenic poisoning: Skin lesions (keratosis, pigmentation), Mees' lines, various cancers.
- Asbestos: Asbestosis, mesothelioma, lung cancer (synergistic with smoking), ferruginous bodies.
- Silicosis: Eggshell calcification (hilar nodes), ↑ TB risk, nodular fibrosis.
- Organophosphates: Acetylcholinesterase inhibition, cholinergic crisis (SLUDGE).
- PM2.5 air pollution: Exacerbates respiratory/cardiovascular diseases, linked to lung cancer.
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