What is a deadly gas produced by vehicles?

Carbon monoxide is a colorless, odorless gas that is produced as a byproduct of incomplete combustion in vehicle engines. When fuel burns, such as gasoline in cars, carbon monoxide can form if there is not enough oxygen available in the combustion process. This gas poses significant health risks, as it can be inhaled and enter the bloodstream, where it binds to hemoglobin more effectively than oxygen, reducing the blood's oxygen-carrying capacity.

While ozone is formed through reactions between sunlight and pollutants and can harm health at ground level, it is not directly emitted by vehicles. Nitrogen oxide is another pollutant produced by vehicles, contributing to smog formation and respiratory issues, but it is not classified as a deadly gas in the same context as carbon monoxide. Carbon dioxide is a greenhouse gas resulting from combustion, but it is not immediately toxic to humans at the levels typically encountered in everyday exposure, unlike carbon monoxide, which can be lethal in higher concentrations. Therefore, the designation of carbon monoxide as a deadly gas produced by vehicles is a critical point for understanding vehicle emissions and their impact on public health.