As an important equipment for real-time monitoring of environmental quality, the installation quality of noise and dust monitoring stations directly affects the accuracy and reliability of monitoring data. The following systematically elaborates on the key control points and technical requirements during the installation process from five dimensions: site selection principles, installation preparation, construction process, commissioning and calibration, and maintenance management.

1、 Scientific Site Selection and Environmental Adaptation

1. Principles of spatial layout

-Monitoring height: The installation height of the noise sensor is 2.5-3.5 meters above the ground to avoid ground reflection interference; The dust sensor (PM2.5/PM10) is recommended to be placed 3-5 meters above the ground, matching the height of the breathing zone.

-Horizontal field of view: Choose an open area to ensure that there are no tall obstacles within a 50 meter radius for noise monitoring, and the dust monitoring path should avoid obstructions such as trees and buildings.

-Pollution source distance: 15-20 meters away from construction dust sources (such as construction site fences), road dust monitoring points should be located downwind and 3-5 meters away from the edge of the lane.

2. Microenvironment assessment

-Electromagnetic interference investigation: Keep away from high-voltage transmission lines (>10 meters), large motor equipment, and frequency converters to avoid radio frequency interference (RFI) affecting data acquisition.

-Vibration isolation: Avoid mechanical vibration sources such as pump rooms and fans, and use shock-absorbing bases if necessary.

-Climate protection: Avoid areas with strong winds and eddies (such as building corners), choose a leeward slope or install windbreaks.

2、 Technical preparation before installation

1. Equipment inspection and accessory verification

-Sensor performance testing: Use a standard sound source (94dB ± 1dB) to calibrate the noise module, and verify the response value of the dust sensor through a particle generator.

-Accessory integrity check: Confirm that the upright pole (hot-dip galvanized steel pipe, diameter ≥ 80mm), solar panel (power matching load), waterproof tank (IP65 and above) and other components are complete.

2. Infrastructure survey

-Geological bearing capacity testing: Portable penetrometer is used to test soil hardness, and a concrete base (size 40cm × 40cm × 50cm) needs to be poured on soft ground.

-Power supply and communication: Confirm the capacity of the mains power access point (AC220V ± 10%) or solar energy storage system, and the 4G/NB IoT signal strength should be ≥ -90dBm.

3、 Standardized installation process

1. Assembly and fixation of uprights

-Pole body splicing: Multiple sections of upright poles are connected using flanges, with a vertical deviation of ≤ 1 °, and waterproof silicone sealing is applied between the flanges.

-Foundation treatment: Excavate a 40cm deep foundation pit, lay a 10cm gravel layer at the bottom, pour C25 concrete, and embed anchor bolts.

-Lightning protection grounding: The grounding electrode adopts ∠ 50 × 5 × 2500mm hot-dip galvanized angle steel, with a grounding resistance of ≤ 4 Ω, and the monitoring station shell is reliably connected to the grounding electrode.

2. Sensor installation specifications

-Noise sensor: Omnidirectional microphone facing H8 (horizontal direction 8), forming a 45 ° angle with the dominant wind direction to avoid direct rain.

-Dust sensor: The optical probe should keep the sampling port horizontal, perpendicular to the dominant wind direction, and have no pollution sources within 1 meter of the surrounding area.

-Meteorological parameter module: The installation height of the wind speed and direction meter is 0.5 meters higher than that of the noise sensor, and the temperature and humidity probe should avoid direct sunlight.

3. Cable laying and protection

-Signal transmission: The RS485 bus adopts RVVSP twisted pair shielded wire, with a length not exceeding 100 meters, and the terminal is connected in parallel with a 120 Ω resistor.

-Power wiring: PVC conduit with a burial depth of ≥ 0.5 meters, exposed cable with flame-retardant sheath, and waterproof junction box at the joint.

-Rat proof measures: Wrap the cable entrance with a metal armor protective layer and inject epoxy resin to seal the pores.

4、 Debugging and Calibration Techniques

1. System integration debugging

-Communication test: Send heartbeat packets to verify the online status of the 4G module, and set the data upload cycle (default 1 minute/time).

-Threshold alarm verification: Simulate exceedance values (such as noise>75dB, PM10>150 μ g/m ³) and check the sound and light alarm function.

2. Precise calibration

-Noise calibration: Use a first level sound level calibrator (such as a piston sounder) to calibrate at the 94dB point, with an error of ≤ 0.5dB.

-Dust calibration: Introduce standard dust aerosols (such as ISO 12103-1 A2 test dust) and adjust the light scattering parameters to ensure that the deviation between the displayed value and the standard value is less than ± 5%.

-Time synchronization: Through Beidou module timing, ensure that the data time scale error is less than 1 second/24 hours.

5、 Operation and maintenance guarantee mechanism

1. Daily inspection content

-Sensor cleaning: Wipe the noise microphone protective cover with a dust-free cloth every week, and blow the dust sampling port every month.

-Data continuity check: Check the platform's reception rate daily, and conduct on-site troubleshooting for abnormal interruptions exceeding 2 hours.

2. Periodic maintenance

-Quarterly calibration: Use standard instruments traceable by metrology institutes to recheck sensor accuracy.

-Annual maintenance: replace aging sealing rings and batteries, and check the corrosion of the upright pole (galvanized layer thickness ≥ 80 μ m).

3. Response to special environments

-Winter antifreeze: The working temperature of the heated sampling tube should be maintained above -20 ℃, and the snow load calculation should meet 0.5kN/m2.

-Typhoon protection: Install cable fixation in areas with wind speeds above level 8, and equip the sensor cabin with a pressure balance valve.