6.4. Suspended particulates (TSP/SPM)

6.4. Suspended particulates (TSP/SPM)

6.4.1. Behaviour, effects, emissions

Particulate matter

Airborne particulate matter represents a complex mixture of organic and inorganic substances, covering a wide range of diameters, from <0.1 µm and up to some 100 µm. Mass and composition tend to divide into two principal groups: coarse particles larger than 2.5 µm in aerodynamic diameter, and fine particles smaller than 2.5 µm in aerodynamic diameter. The smaller particles contain the secondarily formed aerosols (gas to particle conversion), combustion particles and recondensed organic and metal vapours. The bulk of fine particulate mass comprise particles of diameter range 0.1-0.5 µm. The larger particles usually contain earth Crystal materials and fugitive dust from roads and industries. The acid component of particulate matter, and most of its mutagenic activity, is generally contained in the fine fraction, although in fog some coarse acid droplets are also present.

Important parts of the "secondary aerosol" are sulphate particles (important for acid deposition and visibility reduction on the regional scale), and organics-containing particles as a result of photochemical reactions (important in large urban areas with photochemical pollution).

"Suspended particulate matter" is measured and characterised in various ways:

• Total Suspended Particles is the fraction sampled with high-volume samplers, approximately particle diameters <50-100 µm.
• PM10: Inhalable particles, diameter <10 µm. Penetrates through the nose, by nose breathing.
• Thoracic particles: approx. equal PM10.
• PM2.5: "Fine fraction", diameter <2.5 µm. Penetrates to the lungs.
• Black smoke: a measure of the blackness of a particle sample, sampled on a white filter paper, transformed to a mass value (µg/m3) for the particle sample by means of a standard curve. Gives a relative value for the soot content of the sample.

Major sources of primary particles are industrial processes, road traffic, power plants, domestic burning (coal, wood, etc.), incineration, and resuspension of road and construction dust. Particulate matter is removed from the atmosphere by wet and dry deposition.

Short term health effects of exposure to combined SO2, black smoke and particulates include increased mortality, morbidity and deficits in pulmonary function. Some of the "lowest-observed effect" levels for short term exposure to particulate matter are: excess mortality ~500 µg/m3 (smoke); increased acute respiratory morbidity (adults) ~250 µg/m3 (smoke); decrements in lung function (children) ~180 µg/m3 (total suspended particulates)/110 µg/m3 (thoracic particles). Smoke levels of up to 1,500 µg/m3 occurred in the 1952 London smog.

Other environmental effects include the soiling of exposed surfaces, impairment of visibility, potential modification of climate and contribution to acid deposition.

6.4.2. Air Quality Limit and Guide Values

EU Limit values for suspended particulates are given in Table 6.14.

Table 6.14: EU Limit values for suspended particulates (gravimetric method) (µg/m3).
EU Council Directive 80/779/EEC.

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For references, please go to https://www.eea.europa.eu/publications/2-9167-057-X/page021.html or scan the QR code.

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