**Executive Summary**
This document lists NPL (National Physical Laboratory) certified online continuous emission monitoring systems (OCEMS) as of November 21, 2025, with updates on December 1, 2025, and December 10, 2025. It specifies the certificate holder, certificate type, model number, measurable gases/dust, and the certificate number for each system. There are no immediately obvious deadlines or action items indicated.
**Key Points / Main Content**
* **General Information:**
* The list presents NPL certified OCEMS.
* The list was initially compiled on November 21, 2025, with updates on December 1, 2025, and December 10, 2025.
* **System Specifications:**
* Each entry includes the following information:
* **Certificate Holder:** Name of the company holding the certificate.
* **Certificate Type:** Verification Certificate or Provisional Letter of Confirmation.
* **Model No.:** Model number of the OCEMS device.
* **Gases/Dust:** List of gases or dust that the system is designed to monitor (e.g., SO2, NO, CO, PM).
* **Certificate:** NPLI certificate number.
* **Categories of Measurements:**
* Various gases measured include: SO2, NO2, NH3, NO, Formaldehyde, Phenol, H2O, CO, HCI, HF, O2, CO2, N2O, CH4.
* PM (Particulate Matter) measurements are also certified.
**Impact Analysis**
**Stakeholder: Certificate Holders**
**Impact:** Listed as having NPL certified OCEMS. This likely allows them to market and sell the certified systems within applicable regulatory frameworks.
**Action Required:** Ensure compliance with certification standards and maintain the validity of the certificates.
**Stakeholder: Environmental Regulators**
**Impact:** Provides a list of certified OCEMS for use in regulatory monitoring and enforcement activities.
**Action Required:** Utilize the list to verify the certification status of OCEMS deployed by industries and other entities.
**Stakeholder: Industries/Facilities using OCEMS**
**Impact:** Offers a reference for selecting certified OCEMS to meet regulatory monitoring requirements.
**Action Required:** Consult the list when procuring OCEMS to ensure compliance with applicable environmental regulations.
Key Entities Referenced
Online Continuous Emission Monitoring Systems (OCEMS): Systems for monitoring emissions
NPLI CS/CEMS/ VC: Certification standard for continuous emission monitoring systems
NPLI CS/PM-CEMS/VC: Certification standard for particulate matter continuous emission monitoring systems