Gravimetric Particulate Sampling (PM10, PM2.5, Dust)

How does gravimetric sampling work?

In the gravimetric method, a set volume of air is passed through a filter and particles are collected on it. The filter is conditioned at controlled temperature and humidity before and after sampling and weighed on a precision balance. The mass difference divided by the volume of air sampled gives the concentration in µg/m³ or mg/Nm³.

In ambient air, the cut size is determined by the inlet head (PM10, PM2.5, TSP). For stack emissions, isokinetic sampling is applied: the gas velocity at the nozzle is matched to the gas velocity in the stack so that the sample represents the distribution within the duct.

What gravimetric sampling measures and where it is used

Gravimetry is the reference method for measuring particulate mass concentration. Areas of use:

• PM10 and PM2.5 reference measurement in air quality networks
• Verification and field calibration of automated monitors
• Environmental impact assessments
• Stack dust emission measurements
• Additional chemical analyses on filters, such as heavy metals or PAHs

Where gravimetric sampling works well and where it struggles

Because gravimetric measurement relies directly on mass, it serves as a reference and is used to verify other methods. The collected filter can be kept for chemical composition analysis.

Limitations: the result is not instantaneous; the filter requires laboratory weighing and conditioning time. Errors in filter transport, storage and weighing steps are reflected in the result. Loss of volatile components and moisture interaction of the filter material must be managed carefully. Keeping sampling flow constant and maintaining isokinetic conditions requires operator experience.

Related standards

The reference gravimetric method for PM10 and PM2.5 in ambient air is defined in EN 12341. EN 13284-1 is used for isokinetic dust sampling in stacks.

Choosing an instrument for gravimetric sampling

When selecting, the target fraction, sampling flow, filter type, automatic filter changing requirement and environmental conditions are determined. On the laboratory side, consistent filter conditioning and weighing procedures are critical for the traceability of results. Tetra carries out flow calibration and leak tests of samplers as part of periodic service.

Tetra and gravimetric samplers

In Türkiye, Tetra carries out the supply, installation, calibration and service of particulate samplers. For ambient air, Thermo Scientific Partisol 2000i/2025i, the HiVOL high-volume sampler, and Mega System Select One and Lifetek PMS PM10/PM2.5 samplers are offered. For stack emissions, there are Mega System X1 APIS and Lifetek XP-R isokinetic dust sampling systems.