MCQ Detailed View

Exhaust pollutants from vehicles and industrial processes contain several harmful substances, but carbon monoxide (CO) is considered the most hazardous to human health. Carbon monoxide is a colorless, odorless gas that is produced during incomplete combustion of fossil fuels. Unlike carbon dioxide, which is relatively harmless at typical atmospheric concentrations, carbon monoxide can directly affect the body’s ability to carry oxygen.

When inhaled, carbon monoxide binds to hemoglobin in red blood cells with an affinity over 200 times greater than oxygen. This forms carboxyhemoglobin, which prevents oxygen from binding to hemoglobin. As a result, oxygen delivery to vital organs such as the heart and brain is reduced, leading to hypoxia. Symptoms of carbon monoxide poisoning include headache, dizziness, nausea, weakness, and in severe cases, loss of consciousness or death.

Other exhaust pollutants like carbon dioxide (CO₂) contribute to global warming but are not acutely toxic at environmental levels. Lead particles were historically harmful, especially in gasoline, but are less common today due to unleaded fuels. Carbon particles (soot) can irritate the lungs and contribute to respiratory diseases but do not have the immediate systemic effects of carbon monoxide.

Understanding the health hazards of exhaust pollutants is crucial in biology, environmental science, and public health. Knowledge about carbon monoxide emphasizes the importance of vehicle emission controls, proper ventilation, and air quality monitoring to protect human health. This question also helps students link pollution, physiology, and real-life health impacts, which is an important part of everyday science.