A document by Nicholas Violette. Click on the document to view its contents.

Lead exposure has blighted communities across the United States (and the globe), with much of the burden resting on lower income and communities of color. On January 17, 2024, the US Environmental Protection Agency (USEPA) has, after more than 30 years, lowered the allowable level of lead in residential soils. Our analysis of tens of thousands of citizen-science collected soil samples from cities and communities around the US reveals the scale of the soil lead problem, and the challenge that the USEPA will face in implementing its new soil standard. Under this standard, we find that nearly one quarter of households may contain a soil lead hazard. Extrapolating across the nation, that equates to nearly 30 million households needing to mitigate potential soil lead hazards, at a potential total cost of $290 billion to - $1.2 trillion. We do not think this type of mitigation is feasible at the massive scale required and we have instead focused on a more immediate, far cheaper strategy: capping current soils with clean soils and/or mulch. At a fraction of the cost and labor of disruptive conventional soil mitigation, it yields immediate and potentially life-changing benefits for those living in these environments.

Climate change has significantly enhanced dangerous heat events. Many of our institutions are ill-prepared to provide science-informed and rapid interventions to confront this. The GeoHealth community is working to bring science, public health, and medical professionals closer together to grapple with the challenges posed by extreme heat.

Fine particulate matter (PM2.5), with a diameter of 2.5 micrometers or smaller, presents a significant health risk due to its ability to penetrate deeply into the lungs and enter the bloodstream. Conventional exposure assessments often overlook critical factors such as individual movement patterns and spatial variability in pollution, leading to less accurate exposure estimates and masking disparities in vulnerable populations. This study introduces an innovative spatial-temporal agent-based modeling (ABM) approach to capture detailed exposure dynamics within urban airsheds, using the Pleasant Run Airshed in Indianapolis, IN, as a case study. By integrating data from 23 PM2.5 sensors, meteorological variables, and land use data, we modeled PM2.5 concentrations over 50 weeks and simulated exposure for 10,000 virtual agents grouped by susceptibility, reflecting varying levels of health vulnerability. Our results reveal marked exposure disparities across sociodemographic groups, with high-susceptibility agents experiencing significantly greater health impacts. The spatial analysis identifies high-exposure zones near industrial areas and transportation corridors, underscoring the urgent need for targeted environmental justice interventions. This study demonstrates ABM’s potential to capture spatial-temporal exposure variability and illuminate inequities in pollutant exposure, offering critical insights for public health policy to reduce environmental health risks. Future research should explore combining ABM with multi-pollutant analysis to comprehensively address complex urban air quality challenges and promote equitable health outcomes.

Albeit slow and not without its challenges, lead (Pb) emissions and sources in the United States (U.S.) have decreased immensely over the past several decades. Despite the prevalence of childhood Pb poisoning throughout the 20th century, most U.S. children born in the last two decades are significantly better off than their predecessors in regards to Pb exposure. However, this is not equal across demographic groups and challenges remain. Modern atmospheric emissions of Pb in the U.S. are nearly negligible since the banning of leaded gasoline in vehicles and regulatory controls on Pb smelting plants and refineries. This is evident in the rapid decrease of atmospheric Pb concentrations across the U.S over the last four decades. One of the most significant remaining contributors to air Pb is aviation gasoline (avgas), which is minor compared to former Pb emissions. However, continual exposure risks to Pb exist in older homes and urban centers, where leaded paint and/or historically contaminated soils+dusts can still harm children. Thus, while effective in eliminating nearly all primary sources of Pb in the environment, the slow rate of U.S. Pb regulation has led to legacy, secondary sources of Pb in the environment. More proactive planning, communication, and research of commonly used emerging contaminants of concern that can persist in the environment long after their initial use (i.e., PFAS) should be prioritized so that the same mistakes are not made again.

Lead (Pb) is a neurotoxicant that particularly harms young children. Urban environments are often plagued with elevated Pb in soils and dusts, posing a health exposure risk from inhalation and ingestion of these contaminated media. Thus, a better understanding of where to prioritize risk screening and intervention is paramount from a public health perspective. We have synthesized a large national dataset of Pb concentrations in household dusts from across the United States (U.S.), part of a community science initiative called “DustSafe.” Using these results, we have developed a straightforward logistic regression model that correctly predicts whether Pb is elevated (> 80 ppm) or low (< 80 ppm) in household dusts 75% of the time. Additionally, our model estimated 18% false negatives for elevated Pb, displaying that there was a low probability of elevated Pb in homes being misclassified. Our model uses only variables of approximate housing age and whether there is peeling paint in the interior of the home, illustrating how a simple and successful Pb predictive model can be generated if researchers ask the right screening questions. Scanning electron microscopy supports a common presence of Pb paint in several dust samples with elevated bulk Pb concentrations, which explains the predictive power of housing age and peeling paint in the model. This model was also implemented into an interactive mobile app that aims to increase community-wide participation with Pb household screening. The app will hopefully provide greater awareness of Pb risks and a highly efficient way to begin mitigation.

GeoHealth as a research paradigm offers the opportunity to re-evaluate common research engagement models and science training practices. GeoHealth challenges are often wicked problems that require both transdisciplinary approaches and the establishment of intimate and long term partnerships with a range of community members. We examine four common modes of community engagement and explore how research projects are launched, who has the power in these relationships, and how projects evolve to become truly transformative for everyone involved.

Studies of interior air exposures to various human and non-human components has largely been restricted to industrial exposures for the purpose of regulation. In contrast, little attention has been paid to exposure at the residential scale, where people spend much of their day and may be exposed to particulate sources ranging from known toxins, such as lead, arsenic, and asbestos, to human-produced chemicals of yet unknown toxicity, such as flame retardants. To capitalize on experience with citizen science initiatives as they pertain to environmental health, researchers formed an international network called 360 Dust Analysis, which provides guidance on citizen science and interior dust collection, as well as research tools to examine dust through analysis in regional labs. We present initial results from the July 2018 launch of this program in the USA, called DustSafe USA and operated under approved human subjects protocols by Indiana University (http://www.urbanhealth.iupui.edu/). We launched via multiple media strategies, including an extended television news segment, an article in several Indiana newspapers, appearances in several statewide radio shows, and via a widely distributed press release. As of this abstract submission, well over 300 queries were received, and after only two weeks of the launch the lab has received nearly 100 dust samples. Participants are largely from central Indiana where most of the media play occurred, but samples have also come from all over the country. We will present geochemical and compositional results from the dust analysis, but perhaps more importantly we will discuss how citizens were engaged, how the funding model for such efforts might be developed, and the general approach to research translation and citizen science.

Heavy metals are often prevalent in urban settings due to many possible legacy and modern pollution sources, and are essential to quantify because of the potential adverse health effects associated with them. Of particular importance is lead (Pb), because there is no safe level of exposure, and it especially harms children. Through our partnership with community scientists in the Marion County (Indiana, United States) area, we measured Pb and other heavy metal concentrations in various household media. Community scientists completed screening kits that were then analyzed in the laboratory via X-Ray fluorescence (XRF) to quantify heavy metal concentrations in dust, soil, and paint to determine potential hazards in individual homes. Early results point to renters being significantly more likely to contain higher concentrations of Pb, zinc (Zn), and copper (Cu) in their soil versus homeowners, irrespective of soil sampling location at the home, and home age was significantly negatively correlated with Pb and Zn in soil and Pb in dust across all homes. Analysis of paired soil, dust, and paint samples revealed several important relationships such as significant positive correlations between indoor vacuum dust Pb, dust wipe Pb, and outdoor soil Pb. Our collective results point to rental status being an important determinant of possible legacy metal pollution exposure in Indianapolis, and housing age being reflective of both past and possibly current Zn and Pb pollution at the household scale in dust and soil. Thus, future environmental pollution work examining rental status versus home ownership, as well as other household data such as home condition and resident race/ethnicity, is imperative for better understanding environmental justice issues surrounding not just Pb, but other heavy metals in environmental media as well.

GeoHealth represents the critical intersection between the Earth and environmental sciences, and agricultural and health sciences. Following a specific request from the National Science Foundation (NSF) this report provides a series of recommendations aimed at empowering research, building fundamental workforce capacity, and improving communication around GeoHealth to the public and policy makers. This development is critical as a robust GeoHealth research enterprise is essential to global health, human and ecosystem well-being, and sustainability. The AGU community along with those from several allied societies provided the recommendations in this report; these were developed for a detailed survey and two workshops. The survey and other input revealed several broad challenges and needs, including highly siloed funding and support for researchers across institutions and societies, the inability to access or combine key datasets, and in particular the lack of clear career trajectories and support. The recommendations consist of: (i) six programmatic areas where significant attention to building a GeoHealth research enterprise is needed; (ii) approaches and concepts for four specific challenges in GeoHealth for which significant results could be enabled rapidly, within 2-3 years; (iii) ideas for developing an education/career path and for outreach; (iv) larger “moonshot” ideas that might yield very significant impacts over ca. 10 years. All of these have several common elements and themes: they leverage many directorates within NSF, including all within the GEO division; can build off of existing initiatives; are best developed through partnerships with other agencies and communities; and rely on open and FAIR data sets. Although the focus of these recommendations is toward and for the NSF, the suggestions are more general and hopefully will be considered by other funding agencies and other parts of the research enterprise in the U.S. and internationally.

Heavy metal contamination in urban environments, particularly lead (Pb) pollution, is a health hazard both to humans and ecological systems. Despite wide recognition of urban metal pollution in many cities, there is still relatively limited research regarding heavy metal distribution and transport at the household-scale between soils and indoor dusts-the most important scale for actual human interaction and exposure. Thus, using community-scientistgenerated samples in Indianapolis, IN (United States), we applied bulk chemistry, Pb isotopes, and scanning electron microscopy (SEM) to illustrate how detailed analytical techniques can aid in interpretation of Pb pollution distribution at the household-scale. Our techniques provide definitive evidence for Pb paint sourcing in some homes, while others may be polluted with Pb from past industrial/vehicular sources. SEM revealed anthropogenic particles suggestive of Pb paint and the widespread occurrence of Fe-rich metal anthropogenic spherules across all homes, indicative of pollutant transport processes. The variability of Pb pollution at the household scale evident in just four homes is a testament to the heterogeneity and complexity of urban pollution. Future urban pollution research efforts would do well to utilize these more detailed analytical methods on community sourced samples to gain better insight into where the Pb came from and how it currently exists in the environment. However, these methods should be applied after large-scale pollution screening techniques such as portable X-ray fluorescence (XRF), with more detailed analytical techniques focused on areas where bulk chemistry alone cannot pinpoint dominant pollution mechanisms and where community scientists can also give important metadata to support geochemical interpretations.

The air pollutant NO is derived largely from transportation sources, and is known to cause various respiratory diseases. Substantial reduction in transport and industrial processes around the globe stemming from the novel SARS-CoV-2 coronavirus and subsequent pandemic resulted in sharp declines in emissions, including for NO. Additionally, the COVID-19 disease that results from the coronavirus may present in its most severe form in those who have been exposed to high levels of air pollution and thus have various co-morbidities. To explore these links, we compared ground-based NOsensor data from 15 US cities from a one month window in 2019 versus the same window during shutdown in 2020. Levels of NO declined roughly 20-60% in 13 of the 15 cities in 2020, linked to similar declines in traffic volume in those cities. To broaden the spatial analysis beyond the individual ground-based monitors, satellite data for tropospheric NO was also analyzed, and was largely consistent with the ground measurements. Many of the cities studied had a substantial percentage of the population with various pre-existing conditions, and a relationship was found between NO levels, respiratory disease, and COVID-19 case counts. This finding indicates that substantial improvements in air pollution and health outcomes can be achieved quickly with local and state policy directives, perhaps leading to more population-level health resilience in the face of future pandemics.