[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › Environmental and occupational toxicology # Environmental and occupational toxicology How air pollution, solvents, pesticides and other chemicals at home and at work harm health, and how exposure is controlled. Updated Nov 2, 2026 Most people never overdose on a drug, but everyone breathes polluted air or meets chemicals at work. This field studies long, low-level exposures as well as accidents: the pollutants, the organs they damage, the limits set by regulators and the controls that protect workers. ## Key points - Outdoor air pollution (fine particles, ozone, nitrogen dioxide, sulfur dioxide, carbon monoxide) mainly causes heart disease, stroke, COPD, respiratory infections and lung cancer. - Carbon monoxide is colourless and odourless, displaces oxygen in the blood and is treated with oxygen. - Pesticides are a major cause of poisoning; farm workers who apply them face the greatest risk, and they are a leading means of self-poisoning in low- and middle-income countries. - Benzene, a solvent in fuel, damages the bone marrow and causes blood cancers. - The hierarchy of controls ranks protections: elimination, substitution, engineering, administrative controls, then personal protective equipment. ## Air pollutants Fine particles penetrate deep into the lungs and are the main health concern; ozone forms in sunlight from traffic emissions; nitrogen and sulfur oxides come from burning fuel. WHO attributes millions of premature deaths each year to outdoor air pollution, most of them in low- and middle-income countries, mainly from heart disease and stroke. Indoor smoke from cooking fuels adds to the burden. ## Carbon monoxide Carbon monoxide comes from incomplete burning in faulty heaters, stoves and engines. It binds haemoglobin in place of oxygen. Early symptoms (headache, dizziness, nausea) are easily mistaken for flu; severe exposure brings confusion, unconsciousness and lasting brain damage. Treatment is fresh air and oxygen, sometimes hyperbaric oxygen. Detectors near gas appliances prevent it. ## Solvents and industrial chemicals Aromatic hydrocarbons such as benzene, toluene and xylene are common solvents. Short exposures depress the nervous system; long exposure to benzene injures the bone marrow and increases the risk of leukaemia. Workplace limits for such chemicals are set from dose–response data and reviewed over time. ## Pesticides Insecticides are generally more toxic to people than herbicides. Organophosphates and carbamates cause the cholinergic toxidrome; some herbicides, such as paraquat, cause delayed lung injury. Those spraying need protection and bystanders should stay away during and after spraying. International bodies set residue limits for food, and WHO seeks bans on the most toxic and persistent products. ## Protecting workers - Elimination: remove the hazard. - Substitution: use a safer chemical. - Engineering controls: ventilation, enclosure, barriers. - Administrative controls: shorter or less frequent exposure, training. - Personal protective equipment: gloves, masks, suits; the last line, not the first. ## Memory aid Control from the top: Eliminate, Substitute, Engineer, Administer, then Protect (PPE). ## Test yourself Think of the answer, then tap the question to see it. ## Why is carbon monoxide poisoning often missed? The gas cannot be seen or smelled and early symptoms (headache, dizziness, nausea) resemble a viral illness. ## Which workers face the greatest risk from pesticides? Farm workers who apply them, and people nearby during and shortly after spraying. ## Which organ does long-term benzene exposure damage, and with what consequence? The bone marrow; it raises the risk of leukaemia and other blood disorders. ## Why is personal protective equipment the last step in the hierarchy of controls? It depends on each worker using it correctly; the higher steps remove or contain the hazard without relying on behaviour. 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Sources: [Ambient (outdoor) air pollution](https://www.who.int/news-room/fact-sheets/detail/ambient-(outdoor)-air-quality-and-health) (World Health Organization, 2026); [Pesticide residues in food](https://www.who.int/news-room/fact-sheets/detail/pesticide-residues-in-food) (World Health Organization, 2026); [Hierarchy of Controls](https://www.cdc.gov/niosh/hierarchy-of-controls/about/index.html) (National Institute for Occupational Safety and Health (NIOSH), CDC, 2026); [Carbon monoxide poisoning: MedlinePlus Medical Encyclopedia](https://medlineplus.gov/ency/article/002804.htm) (MedlinePlus (U.S. National Library of Medicine), 2026). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/pharmacology/topics/environmental-and-occupational-toxicology/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). 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