UK standards for air quality monitoring instruments
The standard instruments, methods and requirements for monitoring air pollution in the UK.
MCERTS performance standards
Monitoring instruments that are used in UK air pollution monitoring networks must pass the tests and requirements in the MCERTS performance standards.
The MCERTS performance standards make sure that the instruments used to monitor air pollution comply with the:
- Air Quality Standards Regulations 2010
- Environmental Targets (Fine Particulate Matter) (England) Regulations 2023 (England only)
Instrument standards for the Automatic Urban and Rural Network (AURN)
The following table shows the instrument performance standards for common air pollutants. Instruments must meet these standards before they can be approved and certified for use in the AURN.
The documents are produced by the European Committee for Standardisation and published by the British Standard Institute.
| Pollutant | Performance standard | Details |
|---|---|---|
| Benzene | EN 14662-1:2023 | Standard method for measuring benzene by pumped sampling, thermal desorption and capillary gas chromatography |
| Carbon monoxide (CO) | EN 14626:2024 | Standard method for measuring carbon monoxide by non-dispersive infrared spectroscopy |
| Nitrogen oxides (NO and NO2) | BS EN 14211:2024 | Standard method for measuring nitrogen dioxide and nitrogen monoxide by chemiluminescence |
| Ozone (O3) | BS EN 14625:2024 | Standard method for measuring ozone by ultraviolet photometry |
| PM2.5 and PM10 (gravimetric) | BS EN 12341:2023 | Standard gravimetric method for measuring PM2.5 and PM10 in suspended particulate matter |
| PM2.5 and PM10 (continuous) | BS EN 16450:2017 | Automated measuring systems for measuring the concentration of particulate matter (PM2.5 and PM10) |
| Sulphur dioxide (SO2) | BS EN 14212:2024 | Standard method for measuring sulphur dioxide by ultraviolet fluorescence |
Monitoring instruments that measure these pollutants in the AURN must get ‘type approval’ to show they have met the performance standard. Type approval is granted by CSA Group Ltd, the certification body appointed by the Environment Agency.
Testing AURN monitoring instruments against these standards began in 2005.
See a list of monitoring instruments certified by MCERTS.
Find out how the AURN monitors air pollution.
Instrument standards for measuring PM2.5 and PM10
PM2.5 is particulate matter less than 2.5 micrometres in diameter. PM10 is particulate matter less than 10 micrometres in diameter.
The standard methods for measuring PM2.5 and PM10 are:
- BS EN 16450:2017 ambient air (automated system for measuring the concentration of PM2.5 and PM10)
- BS EN 12341:2023 ambient air (standard gravimetric method for measuring PM2.5 and PM10 in suspended particulate matter – the reference method)
Real-time, automatic monitoring
BS EN 16450:2017 sets the minimum performance standard and test procedure for automated continuous measurement systems for PM2.5 and PM10. These systems provide data in near real-time.
Before an automatic PM2.5 or PM10 instrument can be included in the AURN, it must have certification to show that it is equivalent to the standard gravimetric reference method (BS EN 12341:2023).
To demonstrate this equivalence, follow the methods in the guide to the demonstration of equivalence of ambient air monitoring.
Find more information about PM2.5 and PM10 equivalence in the:
- UK Equivalence Working Group PM2.5 Equivalence Programme - a working group position paper
- evidence synthesis report
Non-real-time, non-automatic monitoring
BS EN 12341:2023 sets the standard operating method for gravimetric samplers. However, the filters in gravimetric samplers must be weighed in a laboratory before and after exposure. Because this takes time, the data is not real-time, hourly data.
Additional standards for measuring PM2.5
The Environment Agency requires additional MCERTS certification for measuring PM2.5. This makes sure that all instruments demonstrate equivalence in a representative particulate matter pollution climate for the UK.
To get this certification, monitoring instruments must meet the MCERTS performance standards.
List of approved particulate matter monitoring instruments
This list is in alphabetical order. The list will be updated when new instruments are approved.
| Manufacturer and instrument name | PM size fraction | Correction required |
|---|---|---|
| Envea MP101M | PM2.5 | None |
| Envea MP101M | PM10 | None |
| European reference method in compliance with EN 12341:2023 | PM10 | None |
| European Reference Method in compliance with EN 12341:2023 | PM2.5 | None |
| FAI SWAM 5a 1-Hour dual channel | PM2.5 and PM10 in the same instrument | None |
| FAI SWAM 5a 24-hour dual channel | PM2.5 and PM10 in the same instrument | None |
| FAI SWAM 5a 24-hour single channel | PM10 | None |
| FAI SWAM 5a 24-hour single channel | PM2.5 | None |
| Grimm EDM280 | PM10 | None |
| Grimm EDM280 | PM2.5 | Subtract 1.032 and then divide by 1.022 |
| Met One Smart Heated BAM 1020 | PM10 | Divide by 1.035 |
| Met One Smart Heated BAM 1020 | PM2.5 | None |
| Met One Unheated BAM 1020 | PM10 | Multiply by 0.833 |
| Opsis SM200 | PM10 | None required for real time beta attenuation results. If filter masses are reported, subtract 1.286 then divide by 0.819 |
| Palas Fidas 200, 200E or 200S operating with algorithm method 11’ | PM2.5 and PM10 in the same instrument | None required for PM10. Divide by 1.06 for PM2.5 |
| Palas Fidas 200, 200E or 200S operating with algorithm method 11’ | PM2.5 only | Divide by 1.06 for PM2.5 |
| Thermo Fisher FDMS 1405DF | PM2.5 and PM10 | None |
| Thermo Fisher FDMS 1405F | PM10 | None |
| Thermo Fisher FDMS 1405F | PM2.5 | None |
| Thermo Fisher FDMS 8500 B, C or CB | PM10 | None |
| Thermo Fisher FDMS 8500 B, C or CB | PM2.5 | None |
| Thermo Fisher Partisol 2025 A, B or i | PM10 | None |
| Thermo Fisher Partisol 2025 A, B or i | PM2.5 | None |
Future changes to the MCERTS standards
Instrument standards will be updated in the future to adapt to the changing levels and composition of PM2.5.
Until the standards are reviewed, monitoring instruments must meet the current MCERTS standards.
MCERTS standards under review
The following standards are currently being reviewed and redeveloped:
- BS EN 16450:2017 ambient air (automated system for measuring the concentration of PM2.5 and PM10)
- guide to the demonstration of equivalence of ambient air monitoring methods
Defra will update this page when the new standards are published.