Quality assurance and control in air sampling

Introduction

Air sampling is an essential practice in various fields, including air quality monitoring, environmental analysis, and air emissions regulation. To ensure the reliability and accuracy of collected data, quality assurance (QA) and quality control (QC) play a central role. This blog will look at the importance of quality assurance and quality control at each stage of the air sampling process.

The information is taken from the document produced by the MELCC, entitled: Sampling guide for environmental analysis purposes - Notebook 4 - Sampling of atmospheric emissions from stationary sources .

1. Principles of Quality Assurance and Control

A quality assurance and control (QA/QC) program is a set of measures aimed at guaranteeing the quality of the results obtained during an air sampling campaign. It covers the entire process, from planning to report writing, and encompasses aspects such as management of human resources, material resources and documentation. The primary objectives of QA/QC are to ensure that data is reliable, accurate, and representative, while minimizing errors and enabling rapid problem resolution.

2. QA/QC during Sampling Planning and Preparation

Before you even begin sampling, it is essential to integrate quality assurance and quality control into the planning and preparation of the process. Here are some key things to consider:

• Choice of Sampling Methods : Sampling methods should be selected based on the parameters, substances, emitting source and campaign objectives.

• Required Quality Controls : Quality controls required by sampling methods must be planned, including checking device leaks, calibrating equipment, and using blanks and duplicates.

• Preparation of Forms : The forms necessary for taking data in the field and for sample traceability must be prepared.

• Verification of Equipment : Equipment must be listed, in good working order, clean and properly calibrated. Calibration certificates must be available.

• Sampling Team Qualifications : The sampling team must be sufficiently large and qualified to perform the necessary tasks.

3. QA/QC during Sampling

The field sampling phase is critical for the quality of the data collected. Key QA/QC elements to consider include:

• Preparation and Installation : Sampling devices, equipment and reagents must be prepared and installed in accordance with the sampling methods.

• Field Quality Controls : Quality controls required by the methods must be carried out, such as checking seals, calibrating instruments, and using blanks and duplicates.

• Data Recording : All raw data, including environmental parameters, must be accurately recorded in the field.

• Sample Handling and Traceability : Samples must be handled with care, identified correctly and tracked at every step to ensure their integrity and traceability.

• Response to Non-Conformances : If quality control criteria are not met, corrective action must be taken immediately to ensure the validity of the tests.

4. Post-Sampling QA/QC

After field sampling, sample handling, identification, preservation, transport and analysis are essential to maintain data integrity. QA/QC ensures that:

• Compliant Storage : Samples are stored in accordance with the method specifications or the recommendations of the analytical laboratories.

• Maintained Traceability : Chain of custody forms are completed at every step, from the sampling site to the laboratory, to ensure sample traceability.

5. QA/QC during Sampling Report

Sampling report is the final phase where QA/QC plays a crucial role. He ensures that calculations are performed and verified correctly, that data agrees with field data, and that computer programs are validated. Comparison with previous campaigns can also be carried out to detect trends or variations.

Conclusion

Quality assurance and quality control are essential elements to ensure data reliability and accuracy in air sampling. They help reduce errors, resolve problems quickly and ensure the quality of the results obtained. A rigorous approach to QA/QC is therefore essential to make informed and reliable decisions based on high-quality data.