Analysing particles

Air particles may be inorganic, like the mineral dusts common near roads, quarries and construction activities, or may consist of organic materials such as moulds or fungus.

We sometimes need to examine and analyse particles collected from air samples to determine their composition and any risks to human health.

Techniques involve a wide range of sophisticated analytical methods, including:

  • both conventional and electron microscopes
  • chemical analysis.

Example 1

Examining a sample with a microscope at 2 magnifications (A and B) indicates that it is an organic fibre. Fourier transform infrared spectroscopy (FTIR) analysis confirmed it as polypropylene fibre.

Image of fibres viewed through a microscope

Examining fibres under a microscope

Example 2

A coarse fraction of a sample (A) was further analysed using a scanning electron microscope with an energy dispersive X-ray analyser (SEM-EDS).

Image of dust partiucles viewed through a microscope

Examining dust particles under the microscope

The x-ray spectrum of an individual particle (B) shows a profile typical of feldspar, a common aluminosilicate mineral.

Image of the X-ray spectrum of a dust particle

X-ray spectrum of dust particle (view larger version)

Example 3

Examining a sample of black dust collected on a paper wipe with a microscope at different magnifications (A and B) revealed Ulocladium and Polythrincium fungal spores, common in moist climates.

Image of fungal spores viewed through a microscope

Examining fungal spores under the microscope