Quality assurance

Quality assurance of ambient air measurements 

Air quality measurements require effective quality assurance to ensure that they meet the requirements of the Department for Environment, Food and Rural Affairs (Defra) technical guidance document for local air quality management. Once suitably quality controlled these measurements can then be used in support of local air quality management (LAQM) and compliance assessment.

The proper quality assurance and quality control (QAQC) of air pollution data is essential to ensure accuracy and provide demonstration that the UK complies with the national air quality objectives and air quality standards regulations limit and target values. Find out more about the limit and target values.

NPL has established world-leading expertise in the procedures used to assure the quality of all types of environmental gas and particulate measurements. Quality assurance is delivered in two stages:   

1. Site performance audits
2. Ratification of data

NPL offers both stages of quality assurance covering the following: 

• Site location
• Suitability, current performance and calibration of instrumentation
• Operating practices
• Data storage, processing and statistical procedures
• Calibration procedures and frequency
• Documentation
• Compatibility with national network standards

NPL is UKAS-accredited (Calibration No. 0478) for site performance audits and provides data ratification for the 16 sites making up the Automated London Network, a subset of sites within Defra’s Automatic Urban and Rural Network (AURN). The primary function of the AURN is to provide data in compliance with the UK air quality limit values and targets. In addition, the data and information from the AURN are required by scientists, policy makers and planners to enable them to make informed decisions on managing and improving air quality for the benefit of health and the natural environment.