Determination of free carbon collected on high-volume glass fiber filter

Abstract

Figure 2. Chromatograms of PAN at 100 ppb with the humidity varying from 0% to 100%Column used was 10% Carbowax 400 on Anakrom ABS, 20 in. long, % in. o.d. Oven, 25 °C; carrier flow, 30 ml/min; 63Ni detector tector. In this way, a continuous stream of humidified carrier gas could be added to the column effluent just prior to the detector. The humidity at the detector exist was measured at 30% R.H. Again, samples of PAN at various humidities (0-100%) were injected into the gas chromatograph. The same water anomaly as described earlier resulted.From the experiments we conclude that the most probable cause of this water anomaly is some type of columnsample interaction. Further studies of this phenomenon are under way.Researchers analyzing for PAN by GC-ECD should be aware

Uncertainties in PM2.5 Gravimetric and Speciation Measurements and What We Can Learn from Them

“…This includes sampling artifacts due to adsorption of volatile organic compound (VOC) gases by the quartz fiber filter, leading to positive additive artifacts, 13,18 and evaporation of particles, leading to negative artifacts proportional to the SVOCs. 19 In addition, filter handling procedures and thermal optical analysis protocols can cause artifacts and differences in the OC and EC concentrations.…”

Methods to Assess Carbonaceous Aerosol Sampling Artifacts for IMPROVE and Other Long-Term Networks

“…This approach provides a basis to evaluate artifact correction methods and to estimate the OC artifact in PM 2.5 mass. For most sites, average bQF total carbon (TC) levels ranged from 7 to 11 g per 25-mm filter, which translates to 2-4.3 g/cm 2 . In terms of thermal carbon fractions, each of the OC1 (140°C in 100% helium [He]), OC2 (280°C in 100% He), and OC3 (480°C in 100% He) fractions contributed 2-3 g/filter of TC with very low concentrations found in other carbon fractions.…”

“…This positive OC artifact yields higher values for OC in particulate samples than exist in ambient air. 2 Adsorbed organic vapors also cause differences in elemental carbon (EC) levels determined by reflectance and transmittance corrections during thermal/ optical analysis as they char within the filter. 3,4 Semivolatile organic compounds (SVOCs) can be collected as particles, but portions can evaporate because of increases in temperature or decreases of their gas-phase concentrations in the sampled air, leaving the particle in the gas stream.…”

Carbon in Particulate Matter in the air

“…Prvi po~eci mjerenja EC u uzorcima ~estica u zraku odnosili su se na odre|ivanje EC s pomo}u metode za odre|ivanje crnog dima koja uklju~uje uklanjanje OC i CC nitratnom kiselinom iz uzoraka (31,32,33).…”