National Institute for Occupational Safety and Health

“ Record the mean tare weight of sample filters, W1 and field blanks, B1 (μg) . 3. Weighing procedure: a. Equilibrate the filters or weighing cups in an environmentally controlled weighing area or chamber for at least two hours. b. Zero the balance before each weighing. c. Using forceps, pass each filter or weighing cup over a static neutralizer. Repeat this step if the filter or weighing cup does not release easily from the forceps or attracts the balance pan. Static electricity can cause erroneous weight readings. ”

“ Asphalt fumes are considered a potential occupational carcinogen [4] . Benzene, hexane, and acetone are highly flammable. Prepare samples and standards in a well-ventilated hood and avoid skin contact. Use care when working with compressed gases.
PREPARATION OF FILTERS BEFORE SAMPLING:
NIOSH Manual of Analytical Methods (NMAM) , Fourth Edition BENZENE-SOLUBLE & TOTAL PARTICULATE (ASPHALT FUME) : METHOD 5042, Issue 1, dated 15 January 1998 - Page 4 of 7
1. Number the backup pads with a ballpoint pen and place them, numbered side down, in the filter cassette bottom sections. 2. ”

“ W1 = mean tare weight of filter before sampling (μg) W2 = mean post-sampling weight of sample-containing filter (μg) B1 = mean tare weight of field blank filters (μg) B2 = mean post-sampling weight of field blank filters (μg)
BENZENE-SOLUBLE FRACTION MEASUREMENT: 13. Condition clarification unit by rinsing the reservoir with 1.5 mL of benzene. Use nitrogen pressure to force the benzene through the frit. Appropriately dispose of the benzene rinse. 14. Extract benzene-soluble fraction. a. Add 3.0 mL benzene via a 3-mL volumetric pipet to the filter-containing test tube (step 11.e.) ”

“ Zero the balance before each weighing. 10. Process three tared media blanks through the measurement procedures for total particulate and benzene-soluble fraction.
TOTAL PARTICULATE MEASUREMENT: 11. After sampling: a. Allow refrigerated sample cassettes to come to room temperature before proceeding. b. Wipe dust from the external surface of the filter cassette with a moist paper towel to minimize contamination. Discard the paper towel. c. Remove the top and bottom plugs from the filter cassette. Equilibrate sampler for at least two hours in the balance room or environmental chamber. d. ”

“ Nitrogen,* purified and filtered. holder. 2. Personal sampling pump, 1 to 4 L/min, with flexible connecting tubing. 3. Balance, readable to 0.001 mg. 4. Static neutralizer, 210Po; replace according to manufacturer’s recommendations. 5. ”