Impacts of pollutants on human health
Each pollutant has a signature harm: fine particles hurt lungs and heart, heavy metals damage nerves and kidneys, and contaminated water spreads disease.
Pollutants and their health effects
| Pollutant | Main source | Health effect |
|---|---|---|
| PM2.5 and PM10 | Vehicles, industry, burning, dust | Asthma, lung and heart disease; PM2.5 reaches deep into the lungs and blood |
| Carbon monoxide | Incomplete combustion, vehicle exhaust | Binds haemoglobin and cuts oxygen supply; headache, death at high doses |
| Sulphur dioxide, nitrogen dioxide | Coal power, vehicles | Irritate the airways; bronchitis, asthma attacks |
| Ground-level ozone | Formed from NOx and hydrocarbons in sunlight | Chest pain, reduced lung function |
| Lead | Old paint, batteries, formerly leaded petrol | Harms brain development in children; anaemia |
| Arsenic | Contaminated groundwater | Skin lesions and cancers (arsenicosis) |
| Excess fluoride | Groundwater | Dental and skeletal fluorosis |
| Nitrates | Fertiliser run-off into wells | Blue baby syndrome (methaemoglobinaemia) |
| Pathogens | Sewage in drinking water | Cholera, typhoid, hepatitis A, diarrhoea |
| Noise | Traffic, industry, loudspeakers | Hearing loss, stress, high blood pressure, poor sleep |
Named diseases worth remembering
| Disease | Cause |
|---|---|
| Minamata disease | Methylmercury in fish, Minamata Bay, Japan |
| Itai-itai disease | Cadmium in water and rice, Japan |
| Silicosis | Silica dust from mining and stone cutting |
| Asbestosis | Asbestos fibres |
| Byssinosis | Cotton dust in textile mills |
| Black lung (coal workers' pneumoconiosis) | Coal dust |
Indoor and outdoor air pollution
PM Ujjwala Yojana (2016) gives LPG connections to poor households, cutting indoor smoke.
How NET asks this: match a pollutant with its disease (mercury-Minamata, cadmium-itai-itai, nitrates-blue baby), or link an industrial disaster to the gas involved.
Typical MCQ: “Which heavy metal caused Minamata disease?” Mercury (methylmercury), discharged into Minamata Bay, Japan, and eaten through fish.
Typical MCQ: “Why is carbon monoxide dangerous?” It binds haemoglobin far more strongly than oxygen does, so the blood carries less oxygen.
Minamata = Mercury. Itai-itai means 'it hurts, it hurts' in Japanese: the bone pain of cadmium poisoning.