Research Article
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/m3 |
| Traffic flow | PC | Laser vehicle detector | vehicle/15 min | 15-min accumulative value | LDV | vehicle/15 min | HGV | vehicle/15 min |
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