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Specification for the Construction and Operation of Continuous Emission Monitoring Systems (CEMS) at Polluting Units

2025-11-26

I. Requirements for Discharge Outlet Installation

(1) Entities subject to key management under the pollutant discharge permit system must lawfully install, operate, and maintain automatic pollutant discharge monitoring equipment, which shall be networked with the monitoring systems of the competent ecological and environmental authorities.

(2) The location of discharge outlets must correspond to the details recorded in the completion acceptance and registration of automatic pollution source monitoring facilities.

(3) Environmental protection graphic signage at discharge outlets shall comply with the provisions of GB 15562.1.

II. Requirements for Monitoring Station Building Construction

(1) An independent building shall be provided for outdoor CEMS installations, with the distance between the station building and sampling point not exceeding 70 metres in principle.

(2) The usable floor area of the monitoring station building shall be no less than 12m², with a length ≥4m and width ≥3m. Where more than four instruments are installed, an additional 3m² shall be provided for each additional instrument. The clear height of the station building shall be ≥2.8m, with the indoor floor level ≥0m.

(3) The station building shall be equipped with air conditioning and heating systems to maintain an ambient temperature of 15–30°C and relative humidity ≤60%. The air conditioning system shall feature automatic restart upon power restoration and shall incorporate exhaust fans or ventilation facilities.

(4) The electrical distribution within the station building must satisfy the actual power requirements of the instruments.

(5) Certified standard gases of multiple concentrations within their validity period shall be provided.

(6) The station building shall incorporate waterproofing, moisture-proofing, thermal insulation, and heat retention measures; explosion-proofing is required in specific locations.

(7) Communication conditions necessary for CEMS data transmission shall be ensured.
Reference: Technical Specification for Continuous Emission Monitoring of Flue Gas (SO₂, NOₓ, Particulates) from Fixed Pollution Sources

III. Specifications for the Construction of Automated Monitoring Systems

(1) Sampling Locations

a) Shall be situated at representative positions where pollutants are uniformly distributed, positioned downstream of control equipment and upstream of manual monitoring sections;

b) Shall be selected on vertical pipe sections and within areas of negative pressure within the flue;

c) Shall avoid flue bends and locations with abrupt cross-sectional changes;
d) Where multiple flues converge into a main exhaust duct, sampling points shall be positioned on the main exhaust duct.

(2) Sampling Platforms

a) Platforms shall be readily accessible. At heights ≥2m, inclined ladders/Z-ladders/spiral staircases shall be provided (vertical ladders prohibited). At heights ≥20m, lifting platforms shall be installed. Ladders shall be ≥0.9m wide with an inclination ≤51°, and tread width ≥0.1m; platforms shall be ≥2m in length and width or extend 1m beyond the sampling probe, with guardrails ≥1.5m high and load-bearing capacity ≥300kg/m².

b) Platforms shall provide a clean, dry, oil-free and dust-free reverse-blow air source at 0.6–0.8MPa pressure;

c) A safety power supply shall be installed with a voltage of 198–242V.

(3) Sampling Ports

a) Manual sampling ports shall be reserved downstream of the CEMS monitoring section;

b) Sealed sampling ports with gate valves shall be used for positive pressure or toxic fumes;

c) Equipment sampling ports shall be positioned 0.5–1.3m from the platform, while manual sampling ports shall be 1.2–1.3m away. Multi-level sampling platforms shall be provided where multiple levels are required.
Reference: Technical Specification for On-site Construction of Fixed Pollution Source Automatic Monitoring (Surveillance) Systems

IV. Operational Specifications for Automated Monitoring Systems

(1) Operational Status

a) All components shall remain in good working order and operate normally;

b) Dedicated collection facilities shall be provided for waste liquids from analytical instruments (classified as hazardous waste).

(2) Data Transmission and Storage

a) Data transmission shall function correctly;

b) Data from analytical instruments, data acquisition units, and the monitoring centre must be consistent;

c) Historical data shall be retained in full for at least one year.

(3) Operation, Maintenance and Calibration

Compliance with HJ75-2017 shall be ensured:

a) Routine inspections shall occur at intervals not exceeding seven days;

b) Records shall include shutdowns, fault resolution, consumable replacements, and calibration activities.

(4) Data Correlation

Trends in production load, treatment facility operational status, and automated monitoring data shall be logically consistent.

(5) Operational Parameters

Shall align with those specified during acceptance testing, filing, and the most recent validity review.

V. Operational and Maintenance Qualification Requirements

(1) Operating Entity

a) Must comply with the Administrative Measures for Qualification Licensing of Environmental Pollution Control Facility Operations;

b) Must possess operational qualifications for automatic pollution source monitoring facilities;

c) Must conduct operations and maintenance within the valid qualification period as stipulated.

(2) Personnel Qualifications

Operational, maintenance, and laboratory personnel must undergo training, pass assessments, and hold valid certificates.

(3) Equipment Qualifications

Automatic monitoring facilities shall possess valid qualification documentation:

a) A valid suitability test report issued by the Quality Supervision and Inspection Centre for Environmental Monitoring Instruments under the Ministry of Environmental Protection;

b) An environmental protection product certification certificate;

c) Equipment name and model must match the certificate.

VI. Abnormal Operation Scenarios for Automated Monitoring Facilities

(1) Data Anomalies

a) Prolonged absence of data without valid justification;

b) Data persistently fluctuating around the detection limit;

c) Long-term minor fluctuations around a fixed value;

d) Variation range consistently within 2% of the measurement span;

e) Deviation from supervisory monitoring exceeding the permissible range specified in HJ75;

f) Inconsistencies between analyser, data acquisition instrument, and monitoring centre data;

g) Deviation between analyser and data acquisition instrument exceeding 1%;

h) Deviation between data acquisition instrument and monitoring centre exceeding 1%;

i) Data trends illogically inconsistent with production conditions or treatment facility operation;

j) Other illogical data variations.

(2) Parameter Configuration Anomalies

a) Excessively wide measurement range settings;

b) Failure to adjust parameters or record changes when monitoring conditions alter;

c) Data conversion formulas non-compliant with national standards;

d) Unrecorded modifications to calibration curves.

(3) Facility Status Anomalies

a) Unauthorised shutdown or idling;

b) Unrecorded changes to operational environment;

c) Unrecorded hardware or software modifications.

VII. System Change Management

(1) The type, model, location, and quantity of automatic monitoring facilities and auxiliary equipment must align with acceptance records, filing documentation, and the most recent validity review;

(2) Sampling point locations must align with acceptance records, filing documentation, and the most recent validity review.

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