Significance and Use
The Hi-Vol sampler is commonly used for the collection of the airborne particulate component of the atmosphere. Some physical and chemical parameters of the collected particulate matter are dependent upon the physical characteristics of the collection system and the choice of filter media. A variety of options available for the Hi-Vol sampler give it broad versatility and allow the user to develop information about the size and quantity of airborne particulate material and, using subsequent chemical analytical techniques, information about the chemical properties of the particulate matter.
This test method presents techniques that when uniformly applied, provide measurements suitable for intersite comparisons.
This test method measures the atmosphere presented to the sampler with good precision, but the actual dust levels in the atmosphere can vary widely from one location to another. This means that sampler location may be of paramount importance, and may impose far greater variability of results than any lack of precision in the method of measurement. In particular, localized dust sources may exert a major influence over a very limited area immediately adjacent to such sources. Examples include unpaved streets, vehicle traffic on roadways with a surface film of dust, building demolition and construction activity, or nearby industrial plants with dust emissions. In some cases, dust levels measured close to such sources may be several times the community wide levels exclusive of such localized effects (see Practice D 1357).
1.1 This test method provides for sampling a large volume of atmosphere, 1600 to 2400 m3 (55 000 to 85 000 ft3), by means of a high flow-rate vacuum pump at a rate of 1.13 to 1.70 m3/min (40 to 60 ft3/min) (1, 2, 3 and 4).
1.2 This flow rate allows suspended particles having diameters of less than 100 μm (stokes equivalent diameter) to be collected. However, the collection efficiencies for particles larger than 20 μm decreases with increasing particle size and it varies widely with the angle of the wind with respect to the roof ridge of the sampler shelter and with increasing speed (5). When glass fiber filters are used, particles within the size range of 100 to 0.1 μm diameters or less are ordinarily collected.
1.3 The upper limit of mass loading will be determined by plugging of the filter medium with sample material, which causes a significant decrease in flow rate (see 6.4). For very dusty atmospheres, shorter sampling periods will be necessary. The minimum amount of particulate matter detectable by this method is 3 mg (95 % confidence level). When the sampler is operated at an average flow rate of 1.70 m3/min (60 ft3/min) for 24 h, this is equivalent to 1 to 2 μg/m3 (3).
1.4 The sample that is collected may be subjected to further analyses by a variety of methods for specific constituents.
1.5 Values stated in SI units shall be regarded as the standard. Inch-pound units are shown for information only.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.