During what conditions should emissions testing ideally be performed for accuracy?

Emissions testing should ideally be performed at stable temperatures and humidity levels because these conditions contribute significantly to the accuracy and reliability of the results. When environmental factors like temperature and humidity are fluctuating, they can affect the operation of the vehicle and the performance of the emissions testing equipment. Stable environmental conditions help ensure that the readings obtained during the test reflect the vehicle's emissions performance without outside influences that could skew the data.

Stable temperatures allow for consistent combustion processes within the engine, and stable humidity levels can minimize the impact of moisture, which can also affect emissions readings. Conducting tests under controlled conditions is crucial for assessing compliance with regulations and accurately determining a vehicle's emissions profile.