Apportionment of Ambient Primary and Secondary PM_2.5During a 2001 Summer Intensive Study at the NETL Pittsburgh Site Using PMF2 and EPA UNMIX

Abstract

Apportionment of primary and secondary pollutants during a July 2001 intensive study at the National Energy Technology Laboratory is reported. PM 2.5 was apportioned into primary and secondary contributions using PMF2, and results were compared with apportionment based on UNMIX 2.3. Input to PMF2 included PM 2.5 mass data from four per 24 hour PC-BOSS filters and TEOM, NO x , NO 2 , O 3 , non-volatile, semi-volatile, and volatile organic material, elemental carbon, sulfate, and PIXE determined trace metals. Nine factors were identified in the PMF analysis. Six factors were associated with primary particles from crustal, mobile (gasoline and diesel), and three local sources high in trace metals. Three factors were associated with secondary sources. Two were associated with local emissions dominated by organic material, one was dominated by transported ammonium sulfate. UNMIX was able to identify the two major mobile sources, major local secondary source and transported secondary source. The three major sources of PM 2.5 were identified as secondary transported material (dominated by ammonium sulfate) from west and southwest (46%), secondary material formed during midday photochemical processes (21%), and primary emissions from diesel (10%) and gasoline (8%) mobile sources. The other five sources accounted for the remaining 15% of the PM 2.5. These findings are consistent with the majority of secondary ammonium sulfate in the Pittsburgh area resulting from distant transport, and so decoupled from local activity involving organic pollutants in the metropolitan area. In

Positive sampling artifact of carbonaceous aerosols and its influence on the thermal-optical split of OC/EC

“…More attention should be paid to semivolatile organic carbon in the future (Fig. 1), considering its secondary nature (Modey et al, 2004;Eatough et al, 2006), and its influence on regional haze (Long et al, 2005). Calculation of the attenuation coefficient of EC and PC is essential for the accurate split of OC and EC, based on the current thermal-optical method.…”

Review of Recent Advances in Detection of Organic Markers in Fine Particulate Matter and Their Use for Source Apportionment

“…139,209,210 It has shown good performance at discriminating between source profiles with similar compositions and the ability to find better, cleaner source profiles than can be obtained with UNMIX. 210,211 Likewise, PMF proved better than other models such as CMB, PCA/ absolute principal component scores (APCS), and UNMIX in extracting the major source profiles using a dataset for PM 2.5 mass concentrations at the U.S. Environmental Protection Agency (EPA) Jefferson Street Supersite in Atlanta, GA. 212 Another important aspect of PMF is that it does not rely on information from the correlation matrix but utilizes a point-by-point least-squares minimization scheme. Recently, CMB and PMF approaches were used to estimate the source contributions to PM 2.5 levels with an organic marker compound and it was found that the impact of direct emissions from biomass combustion can be isolated from the effects of primary emissions on secondary sulfate formation.…”

“…that are indicators of atmospheric conversion processes. 139,210,215 The factors identified by PMF must be interpreted as to their probable origin in the atmosphere. Usually this is done by relating the profile of the factor and, if the data are obtained in a short enough time frame, 139,221 on the diurnal patterns of the material associated with the factor.…”

Transport of Atmospheric Fine Particulate Matter: Part 1—Findings from Recent Field Programs on the Extent of Regional Transport within North America

“…17 These sites were characterized by 1-to 3-day episodes during which PM 2.5 concentrations exceeded 40 g/m 3 . These episodes typically involved high sulfate concentrations, with no diurnal variability, associated with long-range transport of pollutants.…”