===== Ambient =====

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**.

==== Common Uses in Health Research ====
  * **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.

==== Etymology ====
  * Derived from Latin *ambiēns*, meaning "going around" or "surrounding".

==== Example ====
  * "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.

==== Related Terms ====
  * [[Household air pollution]]
  * [[PM2.5]]
  * [[Environmental exposure]]
  * [[Global burden modeling]]