We conducted a population-level study to investigate the association between human health and windblown dust in Amarillo, Texas, USA, from 2010 to 2014. We examined whether short-term Dust Exposures (DE) were associated with significant increases in hospitalizations on the day of exposure and for up to seven days afterward, and whether these effects varied by sex, age group, and season. Two DE approaches were analyzed (associated with weather observations, maximum wind speed, visibility, and maximum daily PM _2.5 ) and yielded similar results. Distributed lag nonlinear models in time-series analysis characterized nonlinear relationships between health outcomes and the delayed effects of DE. Diagnoses (both individual and aggregated) with significant associations with DE, ranked from highest to lowest relative risk, included conditions in the perinatal period, neurodegenerative diseases, progression of lung disease, excessive or frequent menstruation, urinary tract infections, blood-forming diseases, nervous system diseases, pneumonia and influenza, respiratory system diseases, septicemia, skin and subcutaneous tissue diseases, birth complications, infectious and parasitic diseases, circulatory system diseases, mental disorders, Associated Diseases, and all ICD-9 Supercategories. The diagnoses of neurodegenerative, respiratory, and associated diseases were also significantly associated with DE in our earlier studies in Lubbock and El Paso counties, Texas. Each city had a distinct set of diagnostic associations with DE, possibly due to differences in dust composition and sources, meteorology, population characteristics, and healthcare access. Exposure to dust events can exacerbate several diagnoses, aggravate inflammation, and lead to infections, highlighting the importance of informing the public about reducing DE and adopting wind-erosion control practices.

The global surge in Autism Spectrum Disorder (ASD) cases, coupled with evidence linking prenatal Particulate Matter (PM) exposure to developmental disruption, demands a comprehensive review to design targeted health interventions. This systematic review and meta-analysis aim to evaluate the strength and consistency of evidence linking prenatal PM exposure to ASD across studies, quantifying this relation to identify actionable environmental risk thresholds. This study employed PRISMA protocols to systematically extract and evaluate evidence from PubMed, Web of Science, Scopus, and ScienceDirect (2010-2024), and screened 4,013 articles to identify qualified case-control and cohort studies (n=29). Data synthesis employed random-effects modeling, accompanied by comprehensive assessment through I2 statistics, Q-tests, funnel plots, Duval and Tweedie's trim-and-fill analysis, and Egger's regression, to ensure validity. A meta-analysis of 16 case-control studies revealed a 34 % increased risk of ASD associated with prenatal PM exposure (pooled OR=1.34; 95 % CI: 1.13-1.54), despite substantial between-study heterogeneity (I2=94.02 %, p<0.001). Publication bias was not significant (Egger's test p value=0.114). Critical trimester-specific analysis uncovered that third-trimester exposure significantly increased ASD risk (OR=1.17; 95 % CI: 1.01-1.34), while first-trimester (OR=1.02; 95 % CI: 0.92-1.11; I2=49.18 %, p<0.10) and second-trimester exposures (OR=1.13; 95 % CI: 0.88-1.38; I2=92.59 %, p<0.001) showed non-significant associations. This review identified prenatal and early life exposure to PM as a risk factor for ASD, indicating a trimester-specific vulnerability. It highlighted the necessity of focused air quality interventions and targeted guidance to reduce prenatal PM exposure to alleviate ASD risk during the critical-window.

This study aimed to assess the trend of reported human coccidioidomycosis (Valley fever or VF) cases and their association with weather and particulate matter (PM) concentrations in El Paso, Texas, USA, in 2013 - 2022. Data on VF incidence was taken from the City of El Paso Notifiable Conditions Reports. Meteorological data were obtained from the National Weather Service, and particulate matter (PM) data was obtained from the Texas Commission on Environmental Quality continuous air monitoring stations. Advanced statistical methods, including Generalized Additive Models (GAMs), were employed to assess the impact of weather and air quality factors on VF incidence. During the study decade, 246 VF cases were recorded. A significant upward trend in incidence rates was evident. Cross-correlation analysis showed VF incidence was positively correlated with average PM2.5 (r=0.16), maximum PM2.5 (r=0.08), average PM10 (r=0.08), and maximum PM10 (r=0.20) from the preceding month. Dust hours were negatively associated with VF incidence of the same month (r= –0.23), while VF incidence had positive associations with average wind speed (r=0.10) and peak wind gust (r=0.13) lagged 4-months. GAM models suggest that a higher VF incidence will be expected when one-month prior maximum temperature exceeds 102 °F (about 38.9 °C), four-month prior peak wind gusts exceed about 28.6 m/s (64 mph), or one-month prior max PM10 exceeds about 2000 µg/m3. Such extreme weather conditions occur in El Paso roughly annually to triennially and suggest intense dust events caused by convection on otherwise non-dusty days may be related to the incidence of VF.

This study assessed photovoltaic (PV) soiling losses at Alamogordo, New Mexico, USA, located within the Chihuahuan Desert and near the White Sands gypsum dune field, a region with frequent dust events. Soiling material collected from PV module surfaces showed seasonal variations in mineral composition, with quartz being the main component during the fall season and calcite predominating during the spring. All samples collected during the following spring season contained large amounts of gypsum, indicating transport from White Sands, supported by HYSPLIT back-trajectories and surface wind data. Soiling materials collected from PV module surfaces generally had a mineral composition similar to that of the surrounding local soils. The mean particle size of collected soiling material samples ranged from 8 to 21 mu m, with similar to 90% of particles being dust (<50 mu m) and similar to 10% of the soiling particles being sand (>50 mu m). Despite Alamogordo experiencing 22 dust events during this study, soiling-related power losses were relatively low, about 2% to 3%, much lower than reported for Global Dust Belt locations. The prevailing south-to-southwest winds and their gusts acted as a passive cleaning mechanism, as they were aligned with the front of the PV modules and likely resuspended particles off panel surfaces. Additionally, relatively low rainfall (about 2.2 mm per hour) was effective in restoring PV performance. These findings suggest that, due to the relatively low soiling losses observed, frequent cleaning may not be necessary at this location, resulting in potential savings in maintenance costs over the long-term operation of the PV system.

Persistent southwest-to-east aeolian transport occurs in the northern Chihuahuan Desert, crossing multiple ephemeral wetlands. We used the rotifer Euchlanis chihuahuaensis as a model species to investigate potential influence of wind dispersal of diapausing propagules along a directional corridor on its population genetics. A regional aeolian corridor was defined using modeled backward trajectories of 36 years of dust events in the northern Chihuahuan Desert. Molecular data from populations inside and outside of the corridor were analyzed to determine phylogenetic relationships, diversity indices, and population structure. We found population structuring with three haplogroups identified within discrete geographic areas in Southern New Mexico, the Paso Del Norte Region, and Northern Mexico. Evidence of long-range dispersal downwind across the corridor included shared haplotypes from hydrologically disconnected habitats similar to 100 - 230 km apart. Furthermore, haplotype diversity was higher outside of the aeolian corridor, with numerous private and population-specific haplotypes, indicative of reduced connectivity among the populations. Nucleotide diversity for populations within the corridor (0.024) was significantly higher than those outside the corridor (0.012). Comparison of variance partitioning revealed that 16.9% of the genetic variation was among populations when comparing populations from inside to those outside the corridor. We conclude that isolated E. chihuahuaensis populations appear to have continued connectivity in the Chihuahuan Desert, likely mediated by the aeolian corridor which provides routes for gene flow. Understanding how passive dispersal shapes genetic structure for aquatic organisms in arid environments, where habitat fragmentation and climatic variability can severely limit connectivity, has broad implications for conservation strategies and management.

Deposition of aeolian (windblown) dust and sand in drylands, such as the El Paso, Texas, USA / Ciudad Juarez, Chihuahua, Mexico metropolitan area within the Chihuahuan Desert, impacts soils, ecosystems, human infrastructure, and air quality. We monitored dry bulk deposition using marble dust collectors (MDCOs), a passive sampler, deployed atop a university building 21m above ground level during synoptic-scale wind events in urban El Paso, for five years (2011-2016). A nearby Texas Commission on Environmental Quality air monitor continuously measured particulate matter concentrations. MDCO sediment deposition rates over five synoptic dust event seasons (October- May) averaged 111 gm-2yr-1 (range 85 - 164 gm-2yr-1), higher than almost all other North American sites but generally lower than Global Dust Belt locations. These deposition rate values, representing only synoptic-scale wind events, underestimate total annual aeolian deposition (augmented by convective dust events and inputs during non-windstorm conditions). Deposition rates were ~2x those reported for rural El Paso County, suggesting urban fugitive dust enhances total dry deposition. Mean grain size of deposited sediment in all events was >50 μm (sand), even though collected ~20 m above the height of saltation, indicating that events in El Paso can be considered "blowing sand" rather than "blowing dust." PM10 concentrations averaged 28 μg/m3 over all collection years but 200 μg/m3 during hours dust was observed, were extremely variable, and were significantly higher during years of strong drought. PM2.5/PM10 ratios averaged 0.13-0.14 during collection periods and dust hours. PM2.5 concentrations were less strongly variable, showing the roles of dust and drought in PMcoarse in El Paso. Back trajectories during synoptic events were predominantly from the southwest and west, crossing sandy, erodible desert soils and remote-sensing-identified dust hotspots. MDCO sediments were comprised primarily of predominant Chihuahuan Desert soil minerals (quartz, feldspars, and calcite). Compared to global average aeolian deposition of major and minor elements, El Paso samples were enriched in silicon but depleted in aluminum, titanium, and manganese, as well as iron, an element with important ecological, radiative, and human health impacts. El Paso, Texas appears to be one of the dustiest / sandiest cities in North America.

Wind erosion and resulting dust negatively impact the environment and society, but there has been no comprehensive assessment of costs to the United States since the 1990s. Climate and society have changed greatly since then, including changing dustiness, spiking Valley fever infections and increased renewable energy use. By adopting published estimates and calculating emerging costs, we estimate that wind erosion and dust in the United States cost $154.4 billion annually (2017 value). This estimate quadruples the previous assessment and is higher than most other US weather and climate disasters. We also discovered many costs associated with wind erosion that are not accounted for. Our estimate, while conservative, reveals that the economic burden of wind erosion is substantial and investment in dust mitigation could yield large economic benefits. Wind erosion and dust transport present challenges to human wellbeing, health and infrastructure. Last estimated for the United States in the 1990s, present economic costs of wind erosion across the United States have nearly quadrupled, and an updated assessment of vulnerable systems is required.

Writing is involved in all aspects of graduate student research. Here we provide detailed guidance on writing for research, especially for master's theses and PhD dissertations and primarily for physical geography and other earth science students. The main sections of a research paper (Introduction, Literature Review, Methods, Results, Discussion, Conclusions) each have specific requirements of what to include and exclude. While there are many aspects to research writing, they should be thought of as a process leading to a final product. The proposal becomes a well-developed first draft of the Introduction, Literature Review, and Methods sections, with Results, Discussion, and Conclusions added after the data are collected and analyzed. New information and improvement of the writing lead to the frequent updating of all sections. In addition, Research Notes are fundamentally important to the process of research and students should develop the habit of entering and maintaining high-quality notes. The Supplement is where details are presented that are important but not included in the main text. References need to be taken seriously from the beginning of the project and the Abstract is the last major part to be written but must be carefully crafted.

We characterized optical properties (absorption, scattering, and backscattering coefficients, & Aring;ngstr & ouml;m exponents, single scattering albedo) of aerosols during dust events at an urban site in El Paso, Texas using in-situ, real-time measurements. Simultaneous measurements of particulate matter (PM10, PM2.5) and wind data from an adjacent Texas Commission on Environmental Quality Continuous Ambient Monitoring Station are used in this study. Data from both sites was obtained at 5-min resolution. Twenty-seven dust events (15 synoptic, 12 mesoscale) occurred during 24 days from April-June 2021. HYSPLIT and STILT back-trajectories indicated many dust events (similar to 46 %) originated from the west-southwest (favoring transport across dust source areas in the Chihuahuan Desert). Mean absorption & Aring;ngstr & ouml;m exponent values of El Paso dust (1.19 and 1.15 for synoptic and mesoscale events) were lower than published values for "pure" dust at other locations (generally accepted as greater than 2). Single scattering albedo values averaged 0.94 during synoptic and mesoscale dust events, confirming the scattering nature of mineral dust in the region. PM10 and PM2.5 concentrations averaged 191 and 41 mu g/m(3) during dust event periods versus 28 and 8.7 mu g/m(3) during non-event (background) periods. Absorption / scattering & Aring;ngstr & ouml;m exponent ratios of dust event aerosols were representative of large particles-black carbon mixture rather than a "pure" dust, suggesting mixing with urban aerosols, while many observations during non-event periods fall into the large particles-black carbon mixture and large particles-low absorption categories, suggesting that dust is a constant key component of the aerosols in El Paso. The 5-min time resolution revealed the evolution of complex aerosol events (e.g., brown carbon followed by dust, multiple dust events within one day, fireworks, advection of low-absorption gypsum dust from White Sands. New Mexico), emphasizing the importance of detecting and quantifying high intensity, short-duration events "lost" in 24-h or hourly air quality data.

Valley fever (coccidioidomycosis) is an infection posing a significant human health risk, resulting from the soil-dwelling fungi Coccidioides. Although incidence and mortality from coccidioidomycosis are underreported in the United States, and this underreporting may impact public health policy in numerous jurisdictions, its incidence is rising. Underreporting may stem from diagnostic and testing difficulties, insufficient environmental sampling for pathogen detection to determine endemicity, and a shortage of data on Coccidioides dispersion. As climate change creates increasingly arid locations in the US favorable for Coccidioides proliferation, determining its total endemicity becomes more difficult. This literature review examining published research from 2000 to 2025 revealed a paucity of publications examining the endemicity of Coccidioides and research gaps in detection methods, including limited studies on the reliability of sampling for geographical and temporal variations, challenges in assessing various sample materials, poorly defined storage conditions, and the lack of precise, less restrictive, cost-effective laboratory procedures. Addressing these challenges requires interdisciplinary collaboration among Coccidioides researchers, wildlife experts, atmospheric and climate scientists, and policymakers. If these obstacles are solved, standardized approaches for identifying Coccidioides, classified by climate zones and ecoregions, could be developed, saving financial resources, labor, and time for future researchers studying the environmental drivers of coccidioidomycosis.

Texas, including the High Plains andChihuahuan Desert, is one of the dustiest regions in the United States, with dusty weather observed on average 29 days per year in Lubbock and 22 days per year in El Paso in recent decades. 1 Although soil dust, being a "natural" substance, may have originally been thought to be relatively benign in comparison to anthropogenic air pollutants, in the last few decades, multiple studies have clearly shown that human exposure to windblown dust is associated with adverse health effects, particularly respiratory disease and cardiovascular disease. 2 Two recent studies in West Texas cities, El Paso and Lubbock, have revealed a statistically significant increase in hospital admissions for wide ranges of additional conditions in the days following dust events.

Although it is a growing area of investigation in the Global Dust Belt, only a few population-level studies have evaluated the human health associations of windblown dust in North America. We investigated whether acute, short-term dust exposures (DE), in Lubbock, Texas (a medium-sized, dust-prone city in the southern Great Plains, USA) were associated with significant increases in hospitalizations on the day of the exposure and up to 7 days afterward. We used the distributed lag non-linear models in time series analysis to describe non-linear relationship between response outcomes and the delayed effects of exposure over time. We found that increased relative risks of hospitalizations for multiple conditions were associated with the two DE approaches that occurred between 2010 and 2014. Consistent with prior studies of dust health effects in other cities in North America, we identified increased hospitalization risks in Lubbock due to neurodegenerative, atherosclerosis, renal, respiratory, asthma, mental, stroke, neoplasms, ischemia, hematologic, musculoskeletal, and associated diseases (aggregation of all causes each associated with at least 5% of hospitalizations) at various dust exposure days. Associations were modified by age, gender, day of the week, and holiday effects. As climate change increases water stresses on dryland agriculture and long periods of drought, dust exposures are likely to increase for residents of dryland cities and with it the likelihood of adverse health effects on people with preexisting conditions. Additional investigations are needed for other dust-prone population centers worldwide to document the health effects of dust exposures and investigate their causes.

This study utilized MODIS true color satellite imagery to analyse blowing sand and dust events dynamics in the Middle East from 2010 to 2021, focusing on Syria, Iraq, and Jordan. A total of 4923 dust point sources were detected, with a significant concentration (~90 %) located within the Tigris-Euphrates Basin (Nearest Neighbor Ratio = 0.41, р < 0.001). Land cover analysis revealed that bare land, comprising most of the study area, was the predominant source of dust emissions. Wetlands, though only constituting about 1 % of the area, showed the highest frequency of dust sources per unit area, highlighting their role as critical dust emission hotspots. The study emphasizes the impact of drought and anthropogenic factors, such as poor land management, on blowing dust intensity. It suggests the necessity of strategic land management practices, including re-vegetation of arid areas, reducing soil exposure, and implementing wind erosion control measures. To effectively address the transboundary nature of dust emissions, the findings underscore the importance of fostering regional cooperation through mechanisms such as shared environmental monitoring and data exchange platforms, joint management of cross-border natural resources, and collaborative policy making.

Ephemeral wetland surfaces are preferential locations for wind erosion and repositories for resting stages (propagules) of aquatic invertebrates. Dormant propagules can disperse to new habitats via wind (aeolian transport, or anemochory). Wind transport of invertebrate propagules has been documented at local and regional scales, but prior laboratory wind tunnel tests of propagule anemochory neither replicated the predominant natural processes of wind erosion in drylands, saltation-sandblasting, nor determined the viability of experimentally wind-transported propagules. We used a soil saltation wind tunnel to test aeolian erosion, transport, and subsequent viability of propagules from seven aquatic invertebrate species. A propagule-bearing crusted soil surface was prepared, then abraded by saltating silica sand in the wind tunnel to emit aeolian sand and dust. Sediment was collected from three downstream sections of the wind tunnel, representing different transport distances in the environment, and propagules were quantified for each section by species. The wind-eroded material was rehydrated with sterile media to detect hatching of any propagules which survived the sandblasting. Although survival was much lower than in a control experiment without wind tunnel saltation treatment, and hatching rates were lower than those reported from undisturbed egg banks, viable individuals of all wind-tunnel-tested species were detected after hydration. Larger propagules settled closer to the source of entrainment than smaller propagules, indicating a shorter dispersal distance for larger propagules- although only short-distance anemochory may be necessary for dispersal across drainage basins. These results demonstrate that resting stages of many invertebrates can be wind-bombarded from natural surfaces along with sand and dust, dispersed into and transported through the atmosphere, and remain viable. Future investigations of anemochory of aquatic invertebrates from ephemeral waters should use appropriate wind tunnels to evaluate propagule and surface properties as potential adaptations for wind dispersion.

The dust cycle facilitates the exchange of particles among Earth's major systems, enabling dust to traverse ecosystems, cross geographic boundaries, and even move uphill against the natural flow of gravity. Dust in the atmosphere is composed of a complex and ever-changing mixture that reflects the evolving human footprint on the landscape. The emission, transport, and deposition of dust interacts with and connects Critical Zone processes at all spatial and temporal scales. Landscape properties, land use, and climatic factors influence the wind erosion of soil and nutrient loss, which alters the long-term ecological dynamics at erosional locations. Once in the atmosphere, dust particles influence the amount of solar radiation reaching Earth, and interact with longwave (terrestrial) radiation, with cascading effects on the climate system. Finally, the wet and dry deposition of particles influences ecosystem structure, composition, and function over both short and long-term scales. Tracking dust particles from source to sink relies on monitoring and measurement of the geochemical composition and size distribution of the particles, space-borne and ground-based remote sensing, and dust modeling. Dust is linked to human systems via land use and policies that contribute to dust emissions and the health-related consequences of particulate loads and composition. Despite the significant influence dust has in shaping coupled natural-human systems, it has not been considered a key component of the Critical Zone. Here, we demonstrate that dust particles should be included as a key component of the Critical Zone by outlining how dust interacts with and shapes Earth System processes from generation, through transport, to deposition. We synthesize current understanding from global research and identify critical data and knowledge gaps while showcasing case studies from North America.

The drylands of North Africa (Sahara and Sahel) are the world’s largest sources of airborne dust. Clouds of African dust aerosols have been long known to be blown westwards across the Atlantic, and by the 1990s were recognized to be transported across and over Texas. African dust incursions in Texas typically happen several times per year in late spring and summer, manifesting as hazy skies overhead and increased ground-level concentrations of PM2.5 (particulate matter fine enough to be inhaled into the human lower respiratory tract). African dust exposure has many reported human health effects in Europe and the Caribbean, including increased all-cause mortality and increased respiratory and cardiovascular disease morbidity and mortality. In Texas, African dust’s greatest impacts occur in the Houston metropolitan area where it has been quantitatively shown to increase ambient aerosol concentrations. The potential of African dust increasing concentrations of inhalable particulate matter beyond regulatory limits is of concern. A sequence of investigations filtering particles from the air, measuring their concentrations, and subjecting them to elemental analysis documented far-transported African dust’s role in air quality in Houston and Galveston. African dust’s contributions to air pollution have been separated from those of local soils and industrial emissions, and Saharan-Sahelian dust has been indicated to sometimes constitute the majority of PM2.5 mass in Houston. While studies show the presence of inhalable metals and microorganisms including opportunistic pathogens during Saharan air incursions in Houston, the human health effects of African dust in Texas remain yet unspecified and merit further investigation. Keywords: aerosols; Africa, Northern; air pollution; dust; particulate matter; public health; Texas

Drought affects the occurrence and intensity of aeolian dust events in many ecoregions. This study investigated the effects of "drought legacy" (the cumulative temporal persistence of drought's consequences on the earth system) on dust generation, a topic which had not previously been evaluated. We investigated the potential dust/drought legacy relationship in the USA's Southern Great Plains and Chihuahuan Desert ecoregions over 14 years, including the 2011-2012 extreme drought, at spatial distances up to 100 km around dust point sources and for up to 5 years' drought history. At every temporal and spatial scale, drought levels associated with dust initiation points in the two ecoregions were significantly different. Chihuahuan Desert dust sources concentrated in areas of severe to extreme drought, while those in the Southern Great Plains, which experiences greater land use, spanned wider ranges of drought conditions. At short temporal scales of drought (1 week and 1 year), dust initiation in the Chihuahuan Desert was associated strongly with severe to exceptional drought conditions at all spatial extents, while Southern Great Plains dust sources were linked to lower drought intensities. For longer drought histories (the past 2 and 5 years), Chihuahuan Desert dust sources were connected with moderate to severe drought, while Southern Great Plains dust sources were linked to moderate drought, at all spatial extents. Drought's legacies, extending over multiple years and kilometer scales, are shown to have roles in subsequent dust events at regional scales, though they can be regionally modulated by land use practices and ecosystem characteristics.

Soil carbonates are dominantly present in dryland Critical Zone (CZ) and their formation could lead to important long-term carbon sequestration in arid to semiarid soils if the Ca ions were derived from silicate weathering or other non-carbonate sources. In managed CZ systems such as agricultural areas converted from natural drylands, irrigation has profound effects on the dryland CZ inorganic carbon storage, especially by modifying dissolution and precipitation dynamics of soil carbonates via controls of irrigation intensity and water chemistry, soil properties, and hydrological flow paths. These processes could lead to transformation of inorganic carbon in soils and groundwater aquifers underneath drylands. One key knowledge gap in studying soil carbonates from managed dryland CZ systems is to detect the formation of soil carbonates under irrigated conditions and distinguish them effectively from soil carbonates formed under natural conditions.Here, we explore the potential of using U-series and strontium isotopes to investigate the formation timescales and conditions of soil carbonates in both natural and managed dryland CZ in Chihuahua Desert of American Southwest. We obtained new U-series and Sr isotope ratios from mature stage V natural soil carbonates in the Jornada Basin of southern New Mexico and compared to previously published U-series and Sr isotope results for younger Jornada soil carbonates as well as irrigation impacted soil carbonates from the Rio Grande floodplains in west Texas. Specifically, we applied the U-series dating method (238U-234U-230Th) to estimate the timescales of soil carbonate formation under both natural climatic conditions and impacts of modern agriculture irrigation. In addition, we showed that the initial (234U/238U) activity ratios recorded in these soil carbonates reflect the systematic changes of soil infiltration rates in both natural and managed dryland CZ. We also utilized Sr isotope ratios (87Sr/86Sr) in soil carbonates, dust, and irrigation water to trace the Ca sources in soil carbonates from natural and managed dryland CZ. Soil carbonates from both settings were characterized by slightly radiogenic 87Sr/86Sr ratios, consistent with their potential of long-term carbon storage in drylands.U-series and Sr isotope systematics characterize important differences in soil carbonates from natural and managed dryland CZ with respect to their Ca sources, timescales of carbonate formation and transformation, and availability of soil moisture. Soil carbonates formed, accumulated, and transformed in natural drylands with long time scales but under irrigated arid agricultural areas its formation is significantly modified by irrigation and other agriculture practices, with implications for long- and short-term inorganic carbon sequestration in both systems of drylands.

Proton-induced X-ray emission spectroscopy (PIXE) is a long-established method of nondestructive elemental analysis for environmental samples. While a standard method of recovery of solids from rainwater involves filtration onto polysulfone media, PIXE analysis has not typically been used on such substrates. We describe methodologies of the University of North Texas Ion Beam Laboratory for PIXE analysis of dust in Texas rainwater on polysulfone membranes from the National Atmospheric Deposition Program (NADP). PIXE analyses utilized a 2 MeV proton beam of 1 x 1 mm(2) spot size with beam currents of 1-5nA. A 100 mu m Al absorber attenuated X-rays produced by S native to the polysulfone and minimized pileup, allowing use of higher beam currents at the expense of detecting elements of Z < 22. Uniformity of dust deposition on the membranes was evaluated by utilizing Fe concentration as a dust tracer. Areas of uniform particulate deposition with comparable results to averages across the entire membrane were located, allowing reduced acquisition time. GeoPIXE software was used for quantitative analysis, and 18 elements (Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, As, Se, Br, Rb, Sr, Y, Zr, Hg and Pb) were investigated for a collaborative project. Average minimum detection limits (MDL) were <= 10 ng/cm(2) for 21 > Z greater than 36 and 10-30 ng/cm(2) for 36 < Z < 83. Polysulfone is shown to be an appropriate substrate for PIXE analysis of environmental samples, especially when quantification of low-Z elements is not a priority.