Elemental Analysis of Airborne Particles
Air pollution is a continuous concern worldwide. The harmful health effects of human exposure to heavy metals (e.g., lead, arsenic, or cadmium) absorbed into particulate matter and carried through the air is of particular interest.
These particles are principally generated by processes such as combustion. The health and safety monitoring and analysis of the elements present in these airborne particles are performed by industry and environmental protection agencies, as well as research institutes and testing laboratories.
Over time, several spectrometric technologies have been employed. Each has its own pluses and minuses, and the technologies have evolved and improved over the years.
Atomic absorption spectrometry (AAS) was once commonly used for air filter analysis. While often still the most affordable solution per initial purchase price, AAS may suffer from limitations including low dynamic range, chemical interferences, sequential operation (and associated relatively low throughput), safety risks when left unattended, recurring lamp replacement expenses, and the need for frequent recalibration. Thus, other technologies have increasingly replaced it.
Photometers also were used fairly frequently. But these suffer several disadvantages, such as low accuracy for high concentrations, the necessity of more extensive sample preparation, and the lack of simultaneous screening for all targeted elements. With the advent of better technologies shown, photometric analyzers are probably more suitable for measuring alkali metals than the toxic heavy metals most of interest in air particle analysis.
Today, the most commonly used technology for analysis of airborne particles involving inductively coupled plasma (ICP). Depending on desired detection limits—and whether local regulations demand a specific choice—these are inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma optical emission spectrometry (ICP-OES) instruments.