Which conditions of mine air can be measured using specific devices?

The selection of temperature, pressure, velocity, and humidity as measurable conditions of mine air is significant because these factors directly affect the safety and health of workers within mining environments.

Temperature is crucial to monitor as it can rise due to machinery operation or geological activity, potentially leading to dangerous conditions or heat stress for workers. Pressure is important in understanding the stability of the mine environment and whether there is a risk of rock falls or other failures.

Velocity, often referred to as airflow velocity, is essential for ensuring adequate ventilation in the mine. Proper airflow helps to dilute harmful gases and bring fresh air to workers, which is vital for maintaining health.

Humidity also plays a role, as it can influence other factors like the potential for mold growth or the effectiveness of dust control measures. Keeping these variables in check is vital for creating a safe work atmosphere in mining operations.

The other choices, while they include some relevant parameters, do not encompass the full spectrum necessary for monitoring mine air quality comprehensively.