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One of the main causes of air pollution in cities is emissions from vehicles like cars and trucks. Cars emit various pollutants which are bad for human health when inhaled, like 1. Nitrogen oxides (NOx) 2. Carbon monoxide (CO) 3. Carbon dioxide (C02) . 4. Benzene Which of the above pollutants are not tolerated by human beings even at very low levels ?
Explanation
Vehicle emissions are a major source of urban air pollution, releasing nitrogen oxides (NOx), carbon monoxide (CO), and benzene [5]. Nitrogen oxides are highly irritating to the respiratory tract even at low concentrations [4]. Carbon monoxide is a poisonous gas that binds to hemoglobin more readily than oxygen; even low concentrations affect mental function, vision, and alertness [5]. Benzene is a known human carcinogen and air toxic that increases leukemia risk and causes blood disorders [5]. While carbon dioxide (CO2) is a primary greenhouse gas and vehicular pollutant, it is generally tolerated by humans at low ambient levels, as it is a natural component of the atmosphere and only becomes acutely toxic (causing unconsciousness or death) at very high concentrations [5]. Therefore, NOx, CO, and benzene are the pollutants considered intolerable or harmful even at very low exposure levels.
Sources
- [1] Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 17: Contemporary Issues > 1. Air Pollution > p. 38
- [5] https://afdc.energy.gov/vehicles/emissions-pollutants
- [4] https://wwwn.cdc.gov/tsp/mmg/mmgdetails.aspx?mmgid=394&toxid=69
- [2] FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.) > Chapter 11: World Climate and Climate Change > Greenhouse Gases(GHGs) > p. 96