1. Interference with Cellular Respiration:
* Carbon monoxide (CO): This gas binds to hemoglobin in red blood cells with much higher affinity than oxygen, preventing oxygen transport to tissues. This leads to suffocation and cell death.
* Cyanide (CN-): Cyanide inhibits the enzyme cytochrome c oxidase, which is crucial for cellular respiration. This blocks the electron transport chain, preventing ATP production, leading to cellular energy crisis and death.
2. Oxidative Stress:
* Ozone (O3): This gas is highly reactive and can damage lung tissue by oxidizing cells. This can lead to inflammation, shortness of breath, and even lung fibrosis.
* Nitrogen dioxide (NO2): This gas is also a potent oxidizer and can cause similar damage to the lungs, as well as contributing to cardiovascular disease.
3. Neurotoxicity:
* Carbon disulfide (CS2): This gas can interfere with the central nervous system, leading to headaches, dizziness, and even coma.
* Hydrogen sulfide (H2S): This gas is highly toxic and can directly affect the brain, leading to paralysis, coma, and death.
4. Irritation and Inflammation:
* Ammonia (NH3): This gas is a strong irritant, causing burning sensations in the eyes, nose, and throat. It can also damage the lungs and lead to respiratory problems.
* Sulfur dioxide (SO2): This gas is a respiratory irritant, causing inflammation and bronchospasm. It can also contribute to acid rain and damage plants.
5. Other Mechanisms:
* Some gases can also be poisonous by causing physical damage to tissues. For example, chlorine gas (Cl2) can react with water in the lungs to form hydrochloric acid, leading to severe damage.
* Others act as biological toxins, interfering with specific biochemical pathways. For example, phosgene (COCl2), a chemical warfare agent, inhibits enzymes involved in respiration and can lead to pulmonary edema.
It's important to remember that toxicity is a complex issue, and the effects of a gas can vary depending on concentration, exposure time, and individual susceptibility.
For detailed information on specific gases, you can consult reliable sources such as the National Institute for Occupational Safety and Health (NIOSH) or the Centers for Disease Control and Prevention (CDC).
