We describe both the original RACE program developed at UC Davis by Eldred and Harrison for PIXE spectrum analysis on a PDP 15/40 with 48K of memory, and the susbsequent modification and reconfiguration at Brooklyn College to adapt the code for use on an IBM PC/XT.

A particulate aerosol collection system has been developed and tested. The sampling system, designed for a wide range of aircraft, collects size-segregated particulate samples. Design features enable it to compensate for the constraints normally associated with aircraft sampling. Within UCD's PIXE analysis system, high flux, focused beams have been developed to analyze the particulate samples collected.

Annals of the New York Academy of SciencesVolume 338, Issue 1 p. 233-257 SIZE AND COMPOSITION OF VISIBILITY-REDUCING AEROSOLS IN SOUTHWESTERN PLUMES* Edward S. Macias, Edward S. Macias Department of Chemistry Washington University St. Louis. Missouri 63130 Consultant to Meteorology Research, Inc. Work performed while on leave at California Institute of Technology, Pasadena, Calif.Search for more papers by this authorDonald L. Blumenthal, Donald L. Blumenthal Meteorology Research, Inc. Santa Rosa, California 95401Search for more papers by this authorJerry A. Anderson, Jerry A. Anderson SRI International Menlo Park, California 94025Search for more papers by this authorBruce K. Cantrell, Bruce K. Cantrell SRI International Menlo Park, California 94025Search for more papers by this author Edward S. Macias, Edward S. Macias Department of Chemistry Washington University St. Louis. Missouri 63130 Consultant to Meteorology Research, Inc. Work performed while on leave at California Institute of Technology, Pasadena, Calif.Search for more papers by this authorDonald L. Blumenthal, Donald L. Blumenthal Meteorology Research, Inc. Santa Rosa, California 95401Search for more papers by this authorJerry A. Anderson, Jerry A. Anderson SRI International Menlo Park, California 94025Search for more papers by this authorBruce K. Cantrell, Bruce K. Cantrell SRI International Menlo Park, California 94025Search for more papers by this author First published: May 1980 https://doi.org/10.1111/j.1749-6632.1980.tb17124.xCitations: 8 * Supported by the Federal Interagency Energy/Environment Research and Development program, through a contract with the EPA-ESRL Office of Regional Studies. † Consultant to Meteorology Research, Inc. ‡ Work performed while on leave at California Institute of Technology, Pasadena, Calif. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume338, Issue1Aerosols: Anthropogenic and Natural, Sources and TransportMay 1980Pages 233-257 RelatedInformation

Multiple regression analysis is used to interpret the relationship between visibility reduction, pollutants and meteorological conditions. Results indicate that multiple regression is a useful technique for air pollution analysis. Four California sites were analyzed : Los Angeles, Los Alamitos, Bakersfield and Oakland. Each site had site specific variables which reduced visibility. However, sulfur in the 0.65–3.6 μm size range showed a significant relationship to reduced visibility at all sites. The study also indicated that the elemental composition and the particle size were both important in determining the effect of paniculate aerosols on visibility reduction.

It has long been recognized that information on particle size distributions in atmospheric aerosals is necessary for meaningful evaluations of potential health hazards. Such information is also important in establishing particulate sources, transport, transformations, and sinks, especially in combination with elemental and chemical data. While instruments exist to collect size segregated samples of particulates, they are too complex and expensive to encourage use of multiple units in field situations.

The California Air Resources Board has operated an aerosol monitoring network of up to 15 stations since January 1973, using impactors to collect size segregated samples and ion-excited x-ray emission to perform the subsequent elemental analyses. Two-stage Lundgren-type rotary drum impactors with afterfilters collect particles in the 0.1 to 0.6 ..mu..m, 0.6 to 5 ..mu..m, and 5 to 20 ..mu..m size ranges. 18-MeV alpha beams from an isochronous cyclotron are used to excite x-rays in the aerosol samples, which are then detected by a Si(Li) x-ray detector. On-line data collection and reduction codes generate aereal densities for elements between sodium and uranium, with sensitivities in the nanogram per cubic meter range for most elements. During the first year of operation, about 12,000 analyses were performed; each analysis included 15 to 25 elements. Extensive studies with real aerosols were required before the problem of bounce-off for dry, silicious aerosols was solved by coating the drums with 530 ..mu..g/cm/sup 2/ mylar upon which was deposited about 50 ..mu..g/cm/sup 2/ paraffin. Penetration of the Nuclepore final filter contributed important corrections to the smallest size range, based upon the work of Spurney and Lodge. Operation of the collection system was verified through extensive comparisonsmore » on an element by element basis with high-volume filter samplers, and a nominal collection error of +-15% was assigned from these causes.« less

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMonitoring California's aerosols by size and elemental compositionRobert G. Flocchini, Thomas A. Cahill, Danny J. Shadoan, Sandra J. Lange, Robert A. Eldred, Patrick J. Feeney, Gordon W. Wolfe, Dean C. Simmeroth, and Jack K. SuderCite this: Environ. Sci. Technol. 1976, 10, 1, 76–82Publication Date (Print):January 1, 1976Publication History Published online1 May 2002Published inissue 1 January 1976https://pubs.acs.org/doi/10.1021/es60112a008https://doi.org/10.1021/es60112a008research-articleACS PublicationsRequest reuse permissionsArticle Views53Altmetric-Citations50LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Aerosols present upwind and downwind of freeways in the Los Angeles Basin were collected in five particle size ranges by Lundgren impactors with after filters and analyzed for elemental content by ion-excited x-ray emission. The contribution of freeway traffic to total airborne particulate load was obtained by subtracting the local background, measured by an upwind sampler, from the values obtained by downwind samplers on a size by size, element by element basis. This contribution correlated reasonably well with estimates derived from automotive and roadbed expendable rates. Traffic-derived aerosols, normalized to vehicular flow, were considerably lower in mass downwind of depressed roadbed configurations than either at grade or raised configurations. A line source model, combined with literature values for emitted lead, produced good agreement with results obtained in the at grade configuration.

Measurements of the elastic differential cross section for $^{3}\mathrm{He}(p, p)^{3}\mathrm{He}$ have been made at laboratory energies of 18.0, 20.0, 22.5, 25.0, 27.5, 30.0, 35.0, 40.0, 42.7, 45.0, 48.5, and 57.0 MeV, at angles between 14.1 and 165.0\ifmmode^\circ\else\textdegree\fi{} c.m. A phase shift analysis was performed in the energy range from 18.0 to 35.0 MeV using these data and polarization and spin correlation data from other sources. Angular momenta up to $l=4$ were used in the analysis, including tensor and spin coupling terms, while inelastic channels were treated through use of complex phase shifts. The results of the analysis exhibit smooth variation with energy, extending and clarifying results obtained at lower energies. Comparisons are made to resonating group predictions of the energy dependence of the singlet and triplet phase shifts.NUCLEAR REACTIONS $^{3}\mathrm{He}(p, p)$, $E=18.0, 20.0, 22.5, 25.0, 27.5, 30.0, 35.0, 40.0, 42.7, 45.0, 48.5, \mathrm{and} 57.0$ MeV; measured ($E$, ${\ensuremath{\theta}}_{\mathrm{lab}}$); ${\ensuremath{\theta}}_{c}=14 \mathrm{to} 165\ifmmode^\circ\else\textdegree\fi{}$; phase shift analysis, $E=18.0, 20.0, 22.5, 25.0, 27.5, 30.0, \mathrm{and} 35.0$ MeV.

Differential cross sections for elastic scattering of deuterons by $^{4}\mathrm{He}$ were measured at laboratory energies of 29.8, 32.3, 34.8, 37.3, and 39.8 MeV. The angular range extended from 15 to 160\ifmmode^\circ\else\textdegree\fi{} cm in steps of about 5\ifmmode^\circ\else\textdegree\fi{}. The average relative error was 2%, and the uncertainty in the absolute normalization was 2%.NUCLEAR REACTIONS $^{4}\mathrm{He}(d,d)$, $E=29.8, 32.3, 34.8, 37.3, 39.8$ MeV; measured ($E,{\ensuremath{\theta}}_{l}$); ${\ensuremath{\theta}}_{c}=16\ifmmode^\circ\else\textdegree\fi{} \mathrm{to} 159\ifmmode^\circ\else\textdegree\fi{}$.

AbstractRapid changes in methods of energy production and utilization are occurring in California, as elsewhere. The affects of such changes upon atmospheric aerosols have been monitored since January, 1973, as part of the continuing study of California aerosols undertaken by U.C. Davis for the California Air Resources Board. A primary goal of the program is to identify aerosol sources in detail, thus allowing energy related components to be isolated and evaluated at many locations throughout the state.Use of ion-excited x-ray emission as the major (although not exclusive) method of elemental analysis is well suited to this program for a number of reasons. Among them include; 1. The sensitivity allows particle-sized aerosol samples to be easily collected, 2. The low cost (under $6, per sample) allows many samples to be run within a fixed budget, 3, The large number of elements seen in the average sample allows source identification by element to element to weather correlations. In addition, the samples are suitable for light element analysis by alpha scattering, for elements H through Cl, thus allowing an inventory to be made of all the aerosol mass in the atmosphere within the size range of the sampler.

Detectable limits for elemental analyses using protons and alpha particles with a velocity of 4 MeV/amu proved to be essentially the same.