The term ambient refers to the surrounding environmental conditions, particularly those in which humans live, breathe, or are exposed. In public health and environmental science, it commonly describes external exposures present in the general outdoor environment.

• Ambient air pollution:
  • Refers to outdoor air pollutants such as PM2.5, PM10, ozone (O₃), nitrogen dioxide (NO₂), and sulfur dioxide (SO₂).
  • Distinguished from household (indoor) air pollution, which comes from cooking, heating, or smoking inside homes.
• Ambient temperature:
  • Refers to the surrounding air temperature, relevant in studies of heat-related illness or climate change.
• Ambient noise:
  • Refers to background environmental sound, used in studies of urban noise exposure and cardiovascular risk.

• Derived from Latin *ambiēns*, meaning “going around” or “surrounding”.

• “Ambient PM2.5 exposure” refers to fine particulate matter in outdoor air that people are exposed to as part of their everyday environment, often linked to stroke, heart disease, and respiratory conditions.

• Household air pollution
• PM2.5
• Environmental exposure
• Global burden modeling