Which factors are combined in the WBGT index to assess heat stress?

• A. Temperature, humidity, wind speed, and radiant heat
• B. Temperature and altitude only
• C. Humidity and air pressure only
• D. Wind speed and atmospheric CO2

Answer: (A)

WBGT brings together how hot the environment feels by combining three measurements that together reflect heat load on the body: dry-bulb air temperature (the ambient air temperature), natural wet-bulb temperature (which incorporates humidity and the cooling effect of evaporation influenced by wind), and globe temperature (which captures radiant heat from the sun and surroundings). This mix effectively covers temperature, humidity, wind effects on evaporation, and radiant heat. The other options miss key components, such as radiant heat or how humidity and air movement contribute to perceived heat, or they include factors not directly used in WBGT like altitude, air pressure, or CO2.