Nolan F. Mangelson

The measurement of PM2.5, including semi-volatile components, in the EMPACT program: results from the Salt Lake City Study

Abstract The Salt Lake City EPA Environmental Monitoring for Public Access and Community Tracking (EMPACT) project, initiated in October 1999, is designed to evaluate the usefulness of a newly developed real-time continuous monitor (RAMS) for total (non-volatile plus semi-volatile) PM2.5 mass and the health relevance of PM2.5 measured by this method as compared to other measurements of PM2.5 parameters. Ammonium nitrate and semi-volatile organic compounds (SVOC) are significant components of fine particles in many urban atmospheres. These components however, are not properly measured by current EPA accepted methods, such as the PM2.5 FRM, due to loss of semi-volatile material (SVM) from the filter during sampling. Continuous PM2.5 mass measurements are attempted using methods such as the R&P TEOM monitor. This method however, heats the sample to remove particle-bound water. This results in evaporation of significant amounts of semi-volatile material. Similarly, continuous carbonaceous material monitors are expected to lose semi-volatile organic material during sample collection. Continuous RAMS and collocated TEOM monitor data have been obtained at the EMPACT sampling site in Salt lake City, Utah during a 2-year period. Results obtained for the continuous determination of total PM2.5 mass with the RAMS have been validated by comparison with results obtained from collocated PC-BOSS diffusion denuder integrated samples at the EMPACT sampling site in Salt Lake City, Utah during three intensive sampling periods (winter 1999–2000, summer 2000, and winter 2000–2001). While the RAMS is shown to measure total PM2.5, including semi-volatile nitrate and organic material, commercially available semi-continuous TEOM and C monitors do not reliably measure these species.

The formation and stability of sulfite species in aerosols

Recent epidemiological and animal lexicological studies indicate that reactions between SO2 and metal containing aerosols result in the formation of respiratory irritants. These studies point out the importance of understanding in detail the chemical species formed by such interactions. Using a combination of thermometric, ESCA and PIXE analysis techniques, it has been demonstrated that both inorganic and organic S(IV) species are stable constituents of aerosols associated with pollution sources containing SO2 and transition metals or with pollution sources resulting from the combustion of fossil fuels. The data indicate the inorganic sulfite species are present as complexes with Fe(III), Cu(II), Zn(II) and possibly Pb(II). The concentration of these inorganic sulfite species is 10 to 30% of the sulfate concentration in primary aerosols produced by smelters. These inorganic sulfite species tend to be evenly distributed over the various particle sizes. In contrast, the inorganic sulfite in primary aerosols produced by fossil fuel burning sources tends to exist in the <3 μm size range and can vary from a negligible to a major fraction of the sulfur species produced. The factors which control this variability are presently unknown. The principal mode of formation of such species in the ambient atmosphere appears to be via SO2 absorption. Oxidation of S° or S(-II)species to form inorganic sulfite complexes or oxidation of the sulfite species to sulfate are both extremely slow, with time constants on the order of months. Aerosol samples collected from the plume, stack, or flue lines of coal burning facilities or collected in New York City or rural Utah produce sulfite when hydrolyzed with dilute aqueous acid. It is postulated this sulfite is produced from organic-SO2 adducts in the sample. These organic S(IV) containing species are predominantly found in the resptrable size range and are present at from 5 to 50% of the sulfate concentration. It is probable that some of these S(IV) species play an important role in the removal of SO2(g) from the atmosphere to form sulfur containing aerosol species.

Proton induced X-ray emission analysis of biological samples: Some approaches and applications

Abstract The method of proton particle induced X-ray emission (proton PIXE) has been used by several teams of researchers for minor and trace element analysis of many interesting biological samples. The proton PIXE analysis method is often ideal for such samples because it allows for the simultaneous determination of several elements and requires only a small sample. Difficult problems are often encountered in preparing samples suitable for PIXE analysis and considerable imagination has been used to solve these problems. Samples both thick and thin in comparison to the particle-beam range have been used. Thin samples are usually supported on thin foils. Procedures used in preparing thins samples have included wet ashing, dry ashing, nebulization of a suspension, freeze-drying, sectioning with a microtome, and spiking with noninterfering elements. Each method of sample analysis has advantages which must be understood when choosing a method for a particular problem.

Element Accumulation Patterns in Foliose and Fruticose Lichens from Rock and Bark Substrates in Arizona

Abstract Growth form and substrate influences on elemental accumulation patterns were investigated in four lichen species. Two fruticose species (Usnea amblyoclada on rock and Usnea hirta on bark) and two foliose species (Flavoparmelia caperata on rock and Flavopunctelia flaventior on bark) were collected below Massai Point in Chiricahua National Monument in southeastern Arizona, U.S.A. Samples were analyzed for 14 elements. A two-way ANOVA model was used to examine the relationships between substrate and growth form (independent variables) on element accumulation (dependent variable) patterns in lichen samples. In the ANOVA model the growth form variable was significant for K, Ca, Ti, Ba, Fe, Ni Cu, Zn, Pb, Rb, and Sr while the substrate variable was significant for K, Ti, Mn, Fe, Ni, Rb, and Sr. A significant interaction between the two class variables was observed for P, K, Ti, Mn, Fe Ni, Rb, and Sr. Accumulation of sulfur appeared to be independent of both growth form and substrate influences. In this study growth form was a key factor affecting element accumulation patterns in lichens. It is proposed that thallus continuity and orientation, which partially define growth form characteristics, influenced the accumulation of elements from airborne and substrate sources.

Analysis of lichen thin sections by PIXE and STIM using a proton microprobe

Abstract In order to better understand the distribution pattern of mineral elements in lichen tissues, thin sections (15 μm) of the foliose, vagrant soil lichen Xanthoparmelia chlorochroa were examined using proton microprobe Particle induced X-ray emission (PIXE). This technique was used to make two-dimensional scans, with 5 μm resolution, across tissue cross sections of the test species. Element maps for Si, P, S, Cl, K, Ca, Ti, Mn, Fe, Cu, Zn, and As have been prepared. Several elements are strongly localized in the element maps. PIXE data are complimented with STIM, light micrographs, and SEM images. Preliminary data suggest that nuclear microprobe techniques may be useful in elucidating element absorption and transport mechanisms in lichens.

The chemical composition of smelter flue dusts

Abstract The chemical composition of two copper and three lead smelter flue dust samples has been studied by wet chemical analysis techniques for sulfite, sulfate, arsenite, anenate, chloride, fluoride, phosphate and acid species; by photoetoctron spectroscopy; by X-ray diffraction analysis; and by proton induced X-ray emission spectroscopy. The results indicate the acidity, chemical composition, and time stability of the flue samples varies greatly. Specific components identified in the samples include; sulfate, sulfite, bisulfate, elemental sulfur, sulfide, arsenite, arsenate, arsenic suifide, chloride, fluoride, phosphate, Fe(II), Fe(III), total trace metal composition, and the specific compounds As 2 O 3 , PbSO 4 , PbO · PbSO 4 , ZnO, Fe 3 O 4 , and Fe 2 O 3 . Acidity, and die chemical components controlling acidity vary widely among the samples studied. Comparisons of the bulk and surface composition of the samples indicate that the surface species cannot be predicted from the bulk composition. From the data obtained, satisfactory total mass and charge balance is obtained for the major (> 1 wt%) components present in the flue dusts studied.

Sulfur chemistry in a copper smelter plume

Sulfur transformation chemistry was studied in the plume of the Utah smelter of Kennecott Copper Corporation from April to October 1977. Samples were taken at up to four locations from 4 to 60 km from the stacks. Data collected at each station included: SO2 concentration, low-volume collected total paniculate matter, high-volume collected size fractionated paniculate matter, wind velocity and direction, temperature, and relative humidity. Paniculate samples were analyzed for S(IV). sulfate, strong acid, anions, cations, and elemental concentrations using calorimetric, ion Chromatographie, FIXE, ESCA, ion microprobe, and SEM-ion microprobe techniques. The concentration of As in the paniculate matter was used as a conservative plume tracer. The ratios Mo/As, Pb/As, and Zn/As were constant in particulate matter collected at all sampling sites for any particle size. Strong mineral acid was neutralized by background metal oxide and/or carbonate particulates within 40km of the smelter. This neutralization process is limited only by the rate of incorporation of basic material into the plume. Two distinct metal-S(IV) species similar to those observed in laboratory aerosol experiments were found in the plume. The formation of paniculate S(IV) species occurs by interaction of SO2 (g) with both ambient and plume derived aerosol and is equilibrium controlled. The extent of formation of S(IV) complexes in the aerosol is directly proportional to the SO2(g) and paniculate (Cu + Fe) concentration and inversely proportional to the paniculate acidity. S(IV) species were stable in collected paniculate matter only in the neutralized material, but with proper sampling techniques could be demonstrated to also be present in very acidic particles at high ambient SO2(g) concentrations. Reduction of arsenate to arsenite by the aerosol S(IV) complexes during plume transport is suggested. The SO2(g)-sulfate conversion process in the plume is described by a mechanism which is first order in SO2(g). Equations are derived describing sulfur chemistry when both S(IV) and sulfate formation occur in a plume. The formation of sulfate results primarily in the formation of < 0.5 μm particulates. The formation process is not correlated with plume expansion, paniculate acidity, metal content, or S(IV) species. Due to meteorological restrictions on sampling, data were collected only during periods of maximum insolation. The formation of sulfate from SO2(g) in the plume during periods of high insolation is temperature dependent with an apparent activation energy of 16.6 ± 1.4 kcal mol−1 and a k1, value of 0.039h−1 at 25°C.

Influence of growth form on the accumulation of airborne copper by lichens

Lichens are known to accumulate airborne elements. This characteristic makes them useful as biomonitors of air quality. However, direct correlations of element concentrations in the air with element concentrations in lichen thalli are generally unavailable. The purpose of this study was to quantitatively examine the relationship between concentrations of copper in ambient air samples and thalli of foliose and fruticose lichens. Lichen samples from four sites along an air copper gradient were collected and analyzed. Foliose specimens consistently accumulated more than twice as much copper as fruticose specimens at all four sites. The relationship between copper concentrations in foliose and fruticose lichens and ambient air samples along an airborne copper gradient was examined using a stepwise regression model. An R2 value of (0.84) and an F-statistic of (182.5, p<0.001) for the model indicate that variability in lichen copper concentrations between sites is explained by airborne copper concentrations. Based on the regression analysis both foliose and fruticose growth forms appear to accurately predict airborne copper concentrations. A significant interaction between the airborne copper and growth form variables and large differences in the calculated slopes suggests that foliose lichens more efficiently accumulate airborne copper than fruticose lichens.

Characterization of mycobiont adaptations in the foliose lichen Xanthoparmelia chlorochroa (Parmeliaceae).

A cross section of the vagrant soil lichen Xanthoparmelia chlorochroa was analyzed using proton microprobe PIXE. Data were used to generate quantitative, two-dimensional element distribution maps for Al, Si, P, S, Cl, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, As, and Sr. Element maps show differential element partitioning between the stratified layers of the thallus. These data document transfer of inorganic nutrients across the thallus to the algal layer. Inorganic particle entrapment was also evident in the element maps. Dense accumulations of calcium oxalate at the junction of the medulla and the algal layer on the order of 10% by dry mass were discovered. Scanning electron microscopy and thermogravimetric analyses were used to characterize the calcium oxalate region. These data provide evidence for possible functional roles of the calcium oxalate layer, including regulation of water and light. Data also provide support for a mutualistic interpretation of the lichen association.

The Contribution of Sulfate and Nitrate to Atmospheric Fine Particles During Winter Inversion Fogs in Cache Valley, Utah

Abstract Air pollutants were collected in Logan, Cache County, UT, in February 1993 during two periods of atmospheric inversion accompanied by fog. The following atmospheric species were determined: (1) gaseous SO2, NO2 (semi-quantitatively),HNO3, NH3, and HF; (2) fine particulate SO4 =, NO3 -, NH4 +, F–, H+, C, Si, S, K, Ca, Ti, Mn, Fe, Ni, Cu, Zn, Pb, Se, Br, and Sr, and; (3) fine particulate mass, which was calculated. The major components of fine particulate matter were carbonaceous material, ammonium nitrate, and ammonium sulfate, while the soil component was small. Calculated, fine particulate mass averaged 80 μg/m3 and reached concentrations as high as 120 μg/m3. SO2/Sox and NO2/NOy mole ratios generally varied between 0.2 and 0.1 during inversions. These ratios also showed moderate but consistent diurnal patterns. The emission inventory for Cache County indicates sources of SO2 and NOx but not significant amounts of primary sulfate and nitrate. The observations reported here indicate there is sign...