Definition

1. Noun:
   • Asphyxiating gas: A chemical gas that has the effect of making people unable to breathe.
   • Choking gas / Suffocating gas: A gas that causes suffocation by depriving the body of oxygen or by direct toxic action on the respiratory system.

Usage Examples

• Noun:
  • Các lính cứu hỏa phải đeo mặt nạ phòng độc để tránh hơi ngạt. (Firefighters must wear gas masks to avoid the asphyxiating gas.)
  • Trong vụ cháy, nhiều nạn nhân tử vong không phải vì lửa mà vì hơi ngạt. (In the fire, many victims died not from the flames but from suffocating gas.)
  • Hầm mỏ cũ có thể chứa đầy hơi ngạt. (Old mines can be filled with choking gas.)

Advanced Usage

• Technical/Medical Context: Used to describe specific toxic industrial or chemical warfare agents that cause asphyxiation.
  • Chlorine gas was used as a hơi ngạt in World War I. (Khí clo đã được sử dụng như một loại hơi ngạt trong Thế chiến thứ nhất.)
• Figurative Use (Rare): Can be used metaphorically to describe an oppressive or stifling atmosphere.
  • Bầu không khí chính trị ở đó như một thứ hơi ngạt. (The political atmosphere there is like a kind of suffocating gas.)

Variants and Related Words

• Ngạt thở (Verb phrase): To suffocate, to be unable to breathe.
  • Nạn nhân có thể ngạt thở vì khói. (The victim could suffocate from smoke.)
• Chất độc thần kinh (Noun): Nerve gas (a specific, more lethal type of chemical agent).
• Khí độc (Noun): Poisonous gas / Toxic gas (a broader term that includes asphyxiating gases).

Synonyms

• Asphyxiant (n): A substance, especially a gas, that causes asphyxiation.
• Choking agent (n): A type of chemical weapon that injures the respiratory tract.
• Suffocating gas (n): A gas that causes suffocation.

Related Phrases / Compound Terms

• Hơi ngạt chiến tranh (Noun phrase): War gas / Chemical warfare agent.
  • Công ước cấm sử dụng hơi ngạt chiến tranh. (The convention bans the use of war gases.)
• Bị nhiễm hơi ngạt (Verb phrase): To be exposed to/affected by asphyxiating gas.
  • Hàng chục công nhân bị nhiễm hơi ngạt trong vụ rò rỉ. (Dozens of workers were exposed to asphyxiating gas in the leak.)

Notes on Usage

• "Hơi ngạt" is a technical and serious term, primarily used in contexts of industrial safety, military science, firefighting, and accident reports. It is not used in casual everyday conversation.
• The word "hơi" here means "vapor" or "gas", not the adverb "a little" or "slightly". The compound "hơi ngạt" functions as a single noun unit.
• It often appears in warnings and safety instructions, e.g., (Warning: Area contains asphyxiating gas.)

1. Asphyxiating gas