Tianhong TH-2000PMb Dual-Channel Atmospheric Particulate Matter Monitor

Overview

The Tianhong TH-2000PMb is a dual-channel atmospheric particulate matter monitor engineered for simultaneous, real-time quantification of PM₁₀ and PM₂.₅ mass concentrations in ambient air. It operates on the beta-ray attenuation principle—where beta particles emitted from a ¹⁴C source pass through a continuously advancing filter tape loaded with airborne particulates; the degree of attenuation correlates linearly with deposited mass. Unlike single-channel systems requiring sequential or interpolated measurements, the TH-2000PMb implements true parallel measurement via a precision-engineered dual-path sampling architecture. Air enters at a total volumetric flow rate of 33.34 L/min, passes through a certified PM₁₀ inlet (ISO 7708:1995 compliant), and is then split equally by a calibrated dynamic hydraulic splitter into two independent 16.67 L/min streams. One stream feeds directly into the PM₁₀ measurement channel; the other undergoes secondary size-selective separation via a traceable PM₂.₅ cyclone (EN 12341:2014 validated) prior to deposition and beta attenuation analysis. This co-located, isokinetic dual-path design eliminates inter-channel time lag and spatial heterogeneity errors inherent in sequential or multi-instrument deployments.

Key Features

• Dual-channel β-ray attenuation detection with synchronized data acquisition—no temporal interpolation required.
• Dynamic Humidity Compensation (DHS) system integrated into both measurement paths to correct for hygroscopic growth effects on filter-loaded mass, improving accuracy under variable RH conditions (20–95% RH).
• Co-located, same-source sampling: identical air mass distributed across both channels ensures intrinsic comparability between PM₁₀ and PM₂.₅ results.
• Hybrid human-machine interface supporting both tactile membrane keys and capacitive touchscreen operation—optimized for field use under gloves or adverse weather.
• Modular cutter compatibility: supports field-swappable, NIST-traceable cutters for TSP, PM₅, PM₂.₅, PM₁, and PM₁₀—each accompanied by third-party calibration certificates issued by CNAS-accredited laboratories in China.
• Robust industrial enclosure rated IP54, with internal temperature stabilization (±0.5 °C) and pressure-compensated mass flow control (±1% full scale).

Sample Compatibility & Compliance

The TH-2000PMb is designed for continuous unattended operation in fixed-site ambient air quality monitoring networks, mobile platforms, and regulatory compliance stations. Its PM₁₀ and PM₂.₅ inlets meet the aerodynamic diameter cutoff specifications defined in ISO 7708:1995 (PM₁₀) and EN 12341:2014 (PM₂.₅), with laboratory validation reports available upon request. All optional cutters are certified by China’s China National Accreditation Service for Conformity Assessment (CNAS) and referenced against EU Reference Methods (EN 12341). The instrument complies with China’s HJ 653-2013 technical specification for PM monitoring instruments and supports data reporting formats aligned with national environmental information platforms (e.g., CNEMC format). While not pre-certified for U.S. EPA EQOA or EU Type Approval, its metrological architecture aligns with the performance criteria outlined in EPA OTM-11 and ISO 20983:2017 for β-ray based monitors.

Software & Data Management

Embedded firmware enables local storage of 12 months of 1-minute averaged data (PM₁₀, PM₂.₅, temperature, relative humidity, flow rate, beta count rate, tape position) on industrial-grade SD card. Remote access is supported via RS-232, RS-485 (Modbus RTU), and Ethernet (TCP/IP), with optional LTE module integration. Tianhong’s proprietary TMS-Cloud platform provides secure web-based visualization, automated QA/QC flagging (e.g., flow deviation >±5%, tape jam detection), and audit-trail logging compliant with GLP principles. Raw beta-count data and attenuation curves are exportable in CSV and NetCDF formats for third-party modeling (e.g., receptor modeling, source apportionment). Firmware updates follow signed-package protocols to ensure integrity and traceability.

Applications

• Ambient air quality monitoring networks operated by municipal and provincial environmental protection bureaus.
• Long-term trend analysis for PM₂.₅/PM₁₀ ratio assessment—critical for identifying dust vs. combustion dominance in source profiling.
• Regulatory compliance verification at industrial fence-line and urban background sites.
• Research-grade exposure studies requiring synchronous fine and coarse fraction data without inter-channel bias.
• Integration into smart city environmental dashboards with real-time public-facing PM index dissemination.
• Calibration reference for lower-cost optical sensors via collocated deployment and regression-based correction modeling.

FAQ

Does the TH-2000PMb require annual recalibration? Why?

Yes—annual traceable recalibration against gravimetric standards (e.g., EPA Method 201A) is recommended to maintain measurement uncertainty within ±5% for PM₂.₅ and ±7% for PM₁₀, as specified in HJ 653-2013.
Can the instrument operate reliably in high-humidity subtropical climates?

Yes—the integrated DHS system dynamically adjusts for water vapor interference using concurrent RH and temperature readings, validated across 20–95% RH at 15–35 °C.
Is raw beta-count data accessible for custom algorithm development?

Yes—full-resolution 1-second beta pulse counts, tape advancement timestamps, and raw analog sensor outputs are logged and exportable via USB or network interface.
What documentation accompanies certified cutters?

Each cutter includes a CNAS-accredited test report confirming aerodynamic cutoff performance, pressure drop characteristics, and loading efficiency per ISO 29463-3.
Does the system support 21 CFR Part 11-compliant electronic records?

Not natively—but TMS-Cloud can be configured with role-based access control, digital signatures, and immutable audit logs meeting core Part 11 requirements for non-clinical environmental data archives.