Random Forests-Based Operational Status Perception Model in Extra-Long Highway Tunnels with Longitudinal Ventilation: A Case Study in China

Table 1

Monitoring instruments and data.

Data category	Data name	Instrument and model	Unit	Statistical interval
Ambient air	CO	ThermoFisher Model 48i CO Analyzer	ppm	15-min average value
	NO2	ThermoFisher Model 42i Analyzer	ppm
	Air velocity	AZ Instrument 9871	m/s
	PM2.5	ThermoFisher Model 5030i Particulate Monitor	mg/m^3
Traffic flow	PC	Laser vehicle detector	vehicle/15 min	15-min accumulative value
	LDV		vehicle/15 min
	HGV		vehicle/15 min