Determination of Nonsulfuric Acid Particulate Matter From Stationary Sources
This method is for the determination of nonsulfuric acid particulate matter (PM) from stationary sources. Particulate matter is defined as any material that condenses at or above the filtration temperature in the method. This method is similar to Method 5. The main difference between the methods is the temperature the filter is maintained at during collection and a slight change in processing the sample once it's collected.
Samples are collected isokinetically from a source on a pre-tared (to a constant weight) glass fiber filter containing no organic binders maintained at a temperature of 160 ± 4°C (320 ± 25°F). A Method 5 train consisting of a heated probe, heated filter, and series of impingers. The first two impingers are filled with 100mL of water, the third impinger is left empty, and the fourth impinger is filled with 200-300g of silica gel.
The filters used for sample collection must be oven dried at 160°C for 2-3 hours, dessicated to a constant weight (less than or equal to a 0.5mg weight change to the nearest 0.1mg) and pre-tared prior to use. The filter must have a 99.95% efficiency on 0.3 micron dioctyl phthalate smoke particles.
Once the sample has been collected, the filter is removed and placed in a petri dish. If it is necessary to fold the filter, make sure the PM is on the inside of the fold. This is container 1. Container 2 consists of the PM brushed from the probe, probe assembly, and front half of the filter holder and the corresponding acetone rinse. The volume of the impinger contents is recorded and the silica gel is weighed to determine the moisture content of the stack gas.
At the laboratory, the filter is oven dried for 6 hours at 160°C to volatilize any condensed sulfuric acid that may have been collected and dessicated to a constant weight. The amount of PM on the filter is equal to the weight change from the pre-sampling weight and the final constant weight of the filter post-sampling. Container 1 is rinsed with acetone and the rinse is added to Container 2 (measure the volume before adding the rinse). The volume of Container 2 is measured, evaporated to dryness at ambient temperature and pressue, oven dried for 6 hours at 160°C to volatilize any condensed sulfuric acid, and dessicated for 24 hours to a constant weight. The sum of the results of both containers is the total PM for the sample.
(EPA 40CFR Part 60 Appendix A)