Nitrogen Isotopes Reveal High NOx Emissions from Arid Agricultural Soils in the Salton Sea Air Basin.

Air quality management commonly aims to mitigate emissions of oxides of nitrogen (NOx) from combustion, reducing ozone and particulate matter pollution. Despite such efforts, regulations have recently proven ineffective in rural areas like the Salton Sea Air Basin of Southern California, which routinely violates air quality standards. With $2 billion in annual agricultural sales and low population density, air quality in the region is likely influenced by year-round farming. We conducted NOx source apportionment using nitrogen stable isotopes of ambient NO2, which indicate a substantial contribution of soil-emitted NOx. The soil source strength was estimated based on the mean δ15N-NOx from each emission category in the California Air Resources Board's NOx inventory. Our annual average soil emission estimate for the air basin was 11.4 ± 4 tons/d, representing ~30% of the extant NOx inventory, 10× larger than the state's inventory. Therefore, the impact of soil NOx in agricultural regions must be re-evaluated.

Cohort profile: The Assessing Imperial Valley Respiratory Health and the Environment (AIRE) study.

BACKGROUND: The Children's Assessing Imperial Valley Respiratory Health and the Environment (AIRE) study is a prospective cohort study of environmental influences on respiratory health in a rural, southeastern region of California (CA), which aims to longitudinally examine the contribution of a drying saline lake to adverse health impacts in children. OBJECTIVES: This cohort was established through a community-academic partnership with the goal of assessing the health effects of childhood exposures to wind-blown particulate matter (PM) and inform public health action. We hypothesize that local PM sources are related to poorer children's respiratory health. POPULATION: Elementary school children in Imperial Valley, CA. DESIGN: Prospective cohort study. METHODS: Between 2017 and 2019, we collected baseline information on 731 children, then follow-up assessments yearly or twice-yearly since 2019. Data have been collected on children's respiratory health, demographics, household characteristics, physical activity and lifestyle, via questionnaires completed by parents or primary caregivers. In-person measurements, conducted since 2019, repeatedly assessed lung function, height, weight and blood pressure. Exposure to air pollutants has been assessed by multiple methods and individually assigned to participants using residential and school addresses. Health data will be linked to ambient and local sources of PM, during and preceding the study period to understand how spatiotemporal trends in these environmental exposures may relate to respiratory health. PRELIMINARY RESULTS: Analyses of respiratory symptoms indicate a high prevalence of allergies, bronchitic symptoms and wheezing. Asthma diagnosis was reported in 24% of children at enrolment, which exceeds both CA state and US national prevalence estimates for children. CONCLUSIONS: The Children's AIRE cohort, while focused on the health impacts of the drying Salton Sea and air quality in Imperial Valley, is poised to elucidate the growing threat of drying saline lakes and wind-blown dust sources to respiratory health worldwide, as sources of wind-blown dust emerge in our changing climate.

Agricultural burning in Imperial Valley, California and respiratory symptoms in children: A cross-sectional, repeated measures analysis.

Burning of agricultural fields is an understudied source of air pollution in rural communities in the United States. Smoke from agricultural burning contains air toxics that adversely impact respiratory health. Imperial County in southeastern California is a highly productive agricultural valley that heavily employs agricultural burning to clear post-harvest crop remnants. We related individual-level exposure to agricultural burns to parent-reported respiratory symptoms in children. We leveraged the Children's Assessing Imperial Valley Respiratory Health and the Environment (AIRE) cohort of 735 predominantly Hispanic low-income elementary school students in Imperial County. Parents reported children's respiratory health symptoms and family demographic characteristics in questionnaires collected at enrollment and in annual follow-up assessments from 2017 to 2019. Permitted agricultural burns in Imperial County from 2016 to 2019 were spatially linked to children's geocoded residential addresses. We used generalized estimating equations to evaluate prevalence differences (PDs) in respiratory symptoms with increasing exposure to agricultural burning within 3 km in the 12 months prior to each assessment. Nearly half of children (346, 49 %) lived within 3 km of at least one agricultural burn in the year prior to study enrollment. In adjusted models, each additional day of agricultural burning in the prior year was associated with a one percentage point higher prevalence of wheezing (PD 1.1 %; 95 % CI 0.2 %, 2.0 %) and higher bronchitic symptoms (PD 1.0 %; 95 % CI -0.2 %, 2.1 %). Children exposed to four or more days of burning had an absolute increased prevalence of wheezing and bronchitic symptoms of 5.9 % (95 % CI -0.3 %, 12 %) and 5.6 % (95 % CI -1.8 %, 13 %), respectively, compared to no burn exposure. Associations with wheezing were stronger among children with asthma (PD 14 %; 95 % CI -1.4 %, 29 %). To our knowledge, this is the first U.S. study of agricultural burning and children's respiratory health. This work suggests that reducing agricultural burning could improve children's respiratory health.

Consideraciones anestésicas en pacientes sometidos a cirugía para resección de tumores intratorácicos: reporte de caso / Anesthetic considerations in patients undergoing surgery for intrathoracic tumor resection: case report

Resumen: Las grandes masas mediastínicas aumentan los riesgos asociados con la anestesia general. Las complicaciones más temidas en este tipo de pacientes son el colapso de la vía aérea, seguido del colapso cardiovascular. Presentamos el caso de una paciente de 30 años con diagnóstico de sarcoma sinovial con metástasis pulmonar y con la presencia de dos tumores intratorácicos. El objetivo del caso clínico es revisar las implicaciones anestésicas y su manejo en este grupo de pacientes.

Abstract: Large mediastinal masses increase the risks associated with general anesthesia. The most feared complications in this type of patients are the collapse of the airway, leading to cardiovascular collapse. We present the case of a 30-year-old patient diagnosed with synovial sarcoma with pulmonary metastasis, with the presence of two intrathoracic tumors. The objective of the clinical case is to review the anesthetic implications and their management in this group of patients.

Concept of functional dentition and impact on the quality of life of partially edentulous patients / Concepto dentición funcional e impacto en la calidad de vida de los pacientes desdentados parciales

Main Objective: To compare, through the OHIP-7Sp, the impact on the quality of life of partially edentulous patients, according to WHO criteria "with functional dentition", 21 or more teeth and "without functional dentition", less than 21 teeth. Material and Methods: 97 partially edentulous patients were selected between 35 and 75 years old, ASA I or II with ≤ 28 teeth remaining. Were divided in two groups, non-functional dentition (NFD) n=47 and functional dentition (FD) n=50. OHIP-7Sp survey was applied to each patient to measure the impact on quality of life in the seven dimensions considered in this survey. The scale of measurement ranges from 0 to 4, in which 0 is "never" and 4 "always", with a maximum value of 28, considering the instrument in its entirety. Highest score indicates a greater impact on quality of life. For comparison of both groups, the non-parametric Mann-Whitney test was used with a level of 95% significance. Results: Concerning all patients evaluated through the OHIP-7Sp, the mean age was 53 years. There were significant differences in the total OHIP-7Sp score, with a mean and median for the NFD group of 9.53 and 9 and for the FD group 5.02 and 5, respectively. Disaggregating the analysis, significant differences emerged in dimensions 2, 3, 4, 5, and 6 (p<0.05). Conclusion: There was a significantly greater impact on the quality of life, measured with the OHIP-7Sp, in the NFD group compared to the FD group.

Objetivo Principal: Comparar mediante el OHIP-7Sp, el impacto en la calidad de vida de pacientes desdentados parciales, según criterio OMS "con dentición funcional", 21 o más dientes y "sin dentición funcional", menos de 21 dientes. 0 Material y Métodos: Fueron seleccionados 97 pacientes desdentados parciales entre 35 y 75 años, ASA I o II con remanencia de ≤ 28 dientes. Fueron divididos en 2 grupos, dentición no funcional (DNF) n=47 y dentición funcional (DF) n=50. Se aplicó encuesta OHIP-7Sp a cada paciente para medir el impacto en la calidad de vida en las 7 dimensiones que contempla esta encuesta. La escala de medición, abarca de 0 a 4, en la cual 0 es "nunca" y 4 "siempre", con un valor máximo de 28, considerado el instrumento en su totalidad. El puntaje más alto indica un mayor impacto en la calidad de vida. Para la comparación de ambos grupos se utilizó el test no paramétrico de Mann-Whitney con un nivel de significancia del 95%. Resultados: Del total de pacientes evaluados mediante el OHIP-7Sp, el promedio de edad fue de 53 años. Hubo diferencias significativas en el puntaje del OHIP-7Sp total, con una media y mediana para el grupo DNF de 9,53 y 9 y para el grupo DF de 5,02 y 5, respectivamente. Desagregando el análisis, emergieron diferencias significativas en las dimensiones 2, 3, 4, 5, y 6 (p<0,05). Conclusión: Hubo significativamente mayor impacto en la calidad de vida, medido con el OHIP-7Sp, en el grupo DNF comparado con el grupo DF.

La lesión miocárdica en el perioperatorio de cirugía no cardíaca / Myocardial injury in the perioperative period of non-cardiac surgery

Resumen: Estudios recientes sobre las causas de muerte en el postoperatorio de cirugía no cardíaca han identificado a la lesión miocárdica como una complicación que se asocia con eventos cardíacos adversos mayores que aumentan la mortalidad a 30 días. La lesión miocárdica se manifiesta como una elevación de las troponinas cardíacas que se produce durante o a los 30 días después de la cirugía, sin que los pacientes presenten síntomas y sin cambios en el electrocardiograma de superficie. En la actualidad, se busca mejorar el diagnóstico oportuno de esta complicación y desarrollar terapias preventivas. En esta revisión abordamos la evidencia de esta lesión, sus mecanismos fisiopatológicos y su manejo.

Abstract: Recent studies on the death causes in the postoperative period of non-cardiac surgery have identified myocardial injury as a complication that is associated with major adverse cardiac events that increase mortality at 30 days after surgery. This kind of myocardial lesion is characterized by the elevation of the cardiac troponins levels during or in the 30 days after the surgery, without symptoms ischemia or changes in the electrocardiogram. Currently, one main goal has been the timely diagnosis of this complication, besides preventive therapies development. The present review article examines the current body of knowledge of this injury, the physiopathological mechanisms and its management.

Manejo de recursos en crisis, importancia de las ayudas cognitivas en anestesia / Resource management in crisis, importance of cognitive aids in anesthesia

Resumen: Las ayudas cognitivas son herramientas diseñadas para guiar al usuario en situaciones de crisis, tales ayudas proporcionan instrucciones y garantizan que las tareas a realizar durante la emergencia se lleven a cabo con la mayor exactitud y con esto evitar la omisión de la mayor cantidad de pasos o tareas durante el evento. Está demostrado que las ayudas cognitivas aumentan el rendimiento de los anestesiólogos durante las situaciones de crisis simuladas y más cuando se somete al usuario a casos clínicos raros o de baja incidencia. Presentamos el caso de una mujer de 33 años programada a cirugía electiva, la cual acude súbitamente por probable hipertermia maligna desencadenada por desflurane. Un reader encargado de la lectura de las ayudas cognitivas durante el evento guió las acciones así como el tratamiento sintomático y específico posterior al diagnóstico. Actualmente se recomienda no confiar en la memoria en situaciones de crisis, ya que puede haber omisiones importantes en el diagnóstico, tratamiento y pronóstico.

Abstract: Cognitive aids are tools designed to guide the user in crisis situations, such aids provide instructions and ensure that the tasks to be performed during the emergency are carried out with the greatest accuracy and thus avoid the omission of as many steps or tasks during the event. It is demonstrated that cognitive aids increase the performance of anesthesiologists during simulated crisis situations and more when the user is subjected to rare or low incidence clinical cases. We present the case of a 33-year-old woman scheduled for elective surgery, who suddenly presented probable malignant hyperthermia triggered by desflurane. The actions as well as the symptomatic and specific treatment after diagnosis, was guided by a «reader¼ in charge of reading the cognitive aids during the event. It is currently recommended not to rely on memory in crisis situations as there may be important omissions in diagnosis, treatment and prognosis.

The nutritional status of the elderly patient infected with COVID-19: the forgotten risk factor?

BACKGROUND: Since the first cases of COVID-19 were reported in Wuhan, the nutritional status of individuals infected with the virus has not been included in the risk profiles prepared. However, nutritional status, along with other factors, is decisive in the evolution of patients with other infectious diseases. The nutritional status of individuals is considered an indicator of health status. Furthermore, optimal nutritional status transcends the individual, and poor diet in a population can be considered a group risk factor. Evidence exists on the influence that diet has on the immune system and susceptibility to disease. OBJECTIVE: To evaluate the nutritional status of patients older than 65 years who were admitted due to COVID-19 and how this has influenced the evolution of patients. DESIGN: This prospective and observational study was performed in patients with COVID-19 infection confirmed by real-time polymerase chain reaction. Data were collected from the first 24 h of admission. All patients admitted during one month to the wards assigned to COVID-19 infection were included. RESULTS: A total of 83 patients were studied. The statistical study of mortality showed associations with age (p = .005), living in a nursing home (p = .022), a high Charlson Comorbidity Index (p = .039), hypertension (p = .032), comorbidities of dementia (p = .019) and cerebral vascular disease (p = .041), and Barthel Index (p = .010). The analysis of the influence of the nutritional state on mortality revealed a statistical association between malnutrition and mortality in the pooled data analysis (p = .005) and analysis by degrees of malnutrition (p = .27). CONCLUSIONS: Malnutrition was a risk factor as powerful as others such as hypertension, age, and different comorbidities. We must evaluate and treat the nutritional status of elderly patients with COVID-19 infection since it directly affects their evolution.

Has Breast Surgery Shattered the Glass Ceiling? Trends in Female Representation at The American Society of Breast Surgeons Annual Meeting 2009-2019.

BACKGROUND: Our study sought to evaluate gender representation and the impact of gender on the large volume of research presented at The American Society of Breast Surgeons (ASBrS) Annual Meeting, the largest breast surgery meeting in the United States. METHODS: Publicly available ASBrS meeting programs and proceedings from 2009 to 2019 were reviewed to ascertain proportions of female engagement in society positions, contributions to scientific sessions, and subsequent manuscript publications. Trend analyses for temporal changes in gender representation and univariate tests of associations between authorship gender and publication success were performed. RESULTS: Women comprised 44.8% of members of the board of directors, 41.7% of committee chairs, and 54.8% of committee members. There were significant annual increased proportions of female committee members (3.2% per year, p = 0.01) and chairs (6.0% per year, p = 0.03). Women represented > 50% of all speakership positions, except keynote (42.2%). For oral, quickshot, and poster scientific presentations, > 70% of first authors and > 60% of senior authors were women. The meeting-related publication rate with female senior authorship was higher than that with male senior authorship (41.0% vs. 36.3%, p = 0.04). CONCLUSIONS: Although female surgeons remain a minority at most conferences, women have represented the majority of participants in committees, speakership, and scientific presentations at the ASBrS Annual Meeting over the past 10 years. The glass ceiling in breast surgery has been shattered, but efforts to improve gender equity must continue, not only in breast surgery, but all surgical specialties.

Consideraciones anestésicas en pacientes con COVID-19 sometidos a traqueostomía: reporte de caso / Anesthetic considerations in COVID-19 patients undergoing tracheostomy: case report

Resumen: A finales de 2019 se identificó en Wuhan, una provincia de China, el virus causante de la enfermedad por coronavirus (COVID-19), el cual ha afectado a más de 1.5 millones de personas en todo el mundo. La fácil transmisión por aerosoles y contacto directo representa un reto para el personal que manipula la vía aérea de estos pacientes. Presentamos el caso de una mujer de 33 años con diagnóstico de neumonía por COVID-19, a quien se realizó una traqueostomía percutánea por intubación prolongada. El objetivo de esta publicación es revisar las consideraciones anestésicas durante este procedimiento en este grupo de pacientes para lograr disminuir el riesgo de contagio en el personal de salud.

Abstract: At the end of 2019, the virus causing the coronavirus disease (COVID-19) was identified in Wuhan, China, wich has affected more than 1.5 million people worldwide. The easy transmission by aerosols and direct contact, represents a challenge for personnel who manipulate the airway of these patients. We present the case of a 33-year-old woman diagnosed with COVID-19 pneumonia, under prolonged intubation scheduled for tracheostomy. The aim of this report is to review the anesthetic considerations during this procedure in this group of patients, in order to reduce the risk of contagion in health personnel.

Performance of a Low-Cost Sensor Community Air Monitoring Network in Imperial County, CA.

Air monitoring networks developed by communities have potential to reduce exposures and affect environmental health policy, yet there have been few performance evaluations of networks of these sensors in the field. We developed a network of over 40 air sensors in Imperial County, CA, which is delivering real-time data to local communities on levels of particulate matter. We report here on the performance of the Network to date by comparing the low-cost sensor readings to regulatory monitors for 4 years of operation (2015-2018) on a network-wide basis. Annual mean levels of PM10 did not differ statistically from regulatory annual means, but did for PM2.5 for two out of the 4 years. R2s from ordinary least square regression results ranged from 0.16 to 0.67 for PM10, and increased each year of operation. Sensor variability was higher among the Network monitors than the regulatory monitors. The Network identified a larger number of pollution episodes and identified under-reporting by the regulatory monitors. The participatory approach of the project resulted in increased engagement from local and state agencies and increased local knowledge about air quality, data interpretation, and health impacts. Community air monitoring networks have the potential to provide real-time reliable data to local populations.

Developing Youth Environmental Health Literacy and Civic Leadership through Community Air Monitoring in Imperial County, California.

With a rapidly changing climate, new leaders must be trained to understand and act on emerging environmental threats. In California's Imperial Valley, a collaborative of community members, researchers, and scientists developed a community air monitoring network to provide local residents with better air quality information. To expand the reach of the project and to prepare the next generation of youth leaders we developed an internship program to increase environmental health literacy and civic leadership. In the 10-week program, high school students learned about air quality science, respiratory health, community air monitoring, and policies intended to improve air quality. The students learned to present this information to their peers, neighbors, family, and community leaders. The program used participatory approaches familiar to community-engaged research to center the students' experience. Surveys and interviews with the students were used to assess the program and found that the students became more familiar with air quality policies, increased their ability to use air monitoring resources, and increased their own confidence in their ability to effect change. With the growing threats related to environmental hazards, it is vital to prepare youth leaders to understand, communicate, and act.

Community-Engaged Air Monitoring to Build Resilience Near the US-Mexico Border.

Initiated in response to community concerns about high levels of air pollution and asthma, the Imperial County Community Air Monitoring Project was conducted as a collaboration between a community-based organization, a non-governmental environmental health program, and academic researchers. This community-engaged research project aimed to produce real-time, community-level air quality information through the establishment of a community air monitoring network (CAMN) of 40 low-cost particulate matter (PM) monitors in Imperial County, California. Methods used to involve the community partner organization and residents in the development, operation, and use of the CAMN included the following: (1) establishing equitable partnerships among the project collaborators; (2) forming a community steering committee to guide project activities; (3) engaging residents in data collection to determine monitor sites; (4) providing hands-on training to assemble and operate the air monitors; (5) conducting focus groups to guide display and dissemination of monitoring data; and (6) conducting trainings on community action planning. This robust community engagement in the project resulted in increased awareness, knowledge, capacity, infrastructure, and influence for the community partner organization and among community participants. Even after the conclusion of the original research grant funding for this project, the CAMN continues to be operated and sustained by the community partner, serving as a community resource used by residents, schools, researchers, and others to better understand and address air pollution and its impacts on community health, while strengthening the ability of the community to prepare for, respond to, and recover from harmful air pollution.

Assessment of Respiratory Health Symptoms and Asthma in Children near a Drying Saline Lake.

Residents of the Imperial Valley, a rural, agricultural border region in California, have raised concerns over high rates of pediatric asthma symptoms. There is an urgent need to understand the influences and predictors of children's respiratory health in Imperial Valley. We assessed the impacts of sociodemographic, lifestyle, and household factors on children's respiratory health and asthma prevalence by administering a survey to parents of elementary school children (n = 357) in northern Imperial Valley. We observed an overall asthma prevalence of 22.4% and respiratory symptoms and allergies were widely reported, including wheezing (35.3%), allergies (36.1%), bronchitic symptoms (28.6%), and dry cough (33.3%). Asthmatics were significantly more likely to report respiratory symptoms, but high rates of wheezing, allergies, and dry cough were observed among nonasthmatics, suggesting the possibility for underdiagnosis of respiratory impairment in our school-age population. Having an asthmatic mother and exposure to environmental tobacco smoke were also associated with greater odds of asthma. Our findings provide evidence to support community concerns about children's respiratory health, while also suggesting that household and demographic characteristics have limited explanatory power for assessing asthma in this population. This work provides critical baseline data with which to evaluate local environmental factors and their influence on asthma and respiratory symptoms.

Next-Generation Community Air Quality Sensors for Identifying Air Pollution Episodes.

Conventional regulatory air quality monitoring sites tend to be sparsely located. The availability of lower-cost air pollution sensors, however, allows for their use in spatially dense community monitoring networks, which can be operated by various stakeholders, including concerned residents, organizations, academics, or government agencies. Networks of many community monitors have the potential to fill the spatial gaps between existing government-operated monitoring sites. One potential benefit of finer scale monitoring might be the ability to discern elevated air pollution episodes in locations that have not been identified by government-operated monitoring sites, which might improve public health warnings for populations sensitive to high levels of air pollution. In the Imperial Air study, a large network of low-cost particle monitors was deployed in the Imperial Valley in Southeastern California. Data from the new monitors is validated against regulatory air monitoring. Neighborhood-level air pollution episodes, which are defined as periods in which the PM2.5 (airborne particles with sizes less than 2.5 µm in diameter) hourly average concentration is equal to or greater than 35 µg m-3, are identified and corroborate with other sites in the network and against the small number of government monitors in the region. During the period from October 2016 to February 2017, a total of 116 episodes were identified among six government monitors in the study region; however, more than 10 times as many episodes are identified among the 38 community air monitors. Of the 1426 episodes identified by the community sensors, 723 (51%) were not observed by the government monitors. These findings suggest that the dense network of community air monitors could be useful for addressing current limitations in the spatial coverage of government air monitoring to provide real-time warnings of high pollution episodes to vulnerable populations.

The disappearing Salton Sea: A critical reflection on the emerging environmental threat of disappearing saline lakes and potential impacts on children's health.

Changing weather patterns, droughts and competing water demands are dramatically altering the landscape and creating conditions conducive to the production of wind-blown dust and dust storms. In California, such factors are leading to the rapid shrinking of the Salton Sea, a 345 mile2 land-locked "sea" situated near the southeastern rural border region known as the Imperial Valley. The region is anticipated to experience a dramatic increase in wind-blown dust and existing studies suggest a significant impact on the health and quality of life for nearby residents of this predominantly low-income, Mexican-American community. The discussion calls attention to the public health dimensions of the Salton Sea crisis. We know little about the possible long-term health effects of exposure to mobilized lakebed sediments or the numerous toxic contaminants that may become respirable on entrained particles. We draw on existing epidemiological literature of other known sources of wind-blown dust, such as desert dust storms, and related health effects to begin to understand the potential public health impact of wind-blown dust exposure. The increased production of wind-blown dust and environmental exposures to such non-combustion related sources of particulate matter are a growing health threat, due in part to drought coupled with increasing pressures on limited water resources. Recent population-based studies have linked dust storms with cardiovascular mortality, asthma hospitalization and decrease in pulmonary function in both adults and children. A growing number of studies provide evidence of the acute health effects of wind-blown dust exposures among children, which with repeated insults have the potential to influence respiratory health over time. The shrinking of the Salton Sea illustrates a public health and environmental justice crisis that requires action and attention to protect the health and well-being of local communities.

Combining Community Engagement and Scientific Approaches in Next-Generation Monitor Siting: The Case of the Imperial County Community Air Network.

Air pollution continues to be a global public health threat, and the expanding availability of small, low-cost air sensors has led to increased interest in both personal and crowd-sourced air monitoring. However, to date, few low-cost air monitoring networks have been developed with the scientific rigor or continuity needed to conduct public health surveillance and inform policy. In Imperial County, California, near the U.S./Mexico border, we used a collaborative, community-engaged process to develop a community air monitoring network that attains the scientific rigor required for research, while also achieving community priorities. By engaging community residents in the project design, monitor siting processes, data dissemination, and other key activities, the resulting air monitoring network data are relevant, trusted, understandable, and used by community residents. Integration of spatial analysis and air monitoring best practices into the network development process ensures that the data are reliable and appropriate for use in research activities. This combined approach results in a community air monitoring network that is better able to inform community residents, support research activities, guide public policy, and improve public health. Here we detail the monitor siting process and outline the advantages and challenges of this approach.

The Imperial County Community Air Monitoring Network: A Model for Community-based Environmental Monitoring for Public Health Action.

SUMMARY: The Imperial County Community Air Monitoring Network (the Network) is a collaborative group of community, academic, nongovernmental, and government partners designed to fill the need for more detailed data on particulate matter in an area that often exceeds air quality standards. The Network employs a community-based environmental monitoring process in which the community and researchers have specific, well-defined roles as part of an equitable partnership that also includes shared decision-making to determine study direction, plan research protocols, and conduct project activities. The Network is currently producing real-time particulate matter data from 40 low-cost sensors throughout Imperial County, one of the largest community-based air networks in the United States. Establishment of a community-led air network involves engaging community members to be citizen-scientists in the monitoring, siting, and data collection process. Attention to technical issues regarding instrument calibration and validation and electronic transfer and storage of data is also essential. Finally, continued community health improvements will be predicated on facilitating community ownership and sustainability of the network after research funds have been expended. https://doi.org/10.1289/EHP1772

Development and field validation of a community-engaged particulate matter air quality monitoring network in Imperial, California, USA.

The Imperial County Community Air Monitoring Network was developed as part of a community-engaged research study to provide real-time particulate matter (PM) air quality information at a high spatial resolution in Imperial County, California. The network augmented the few existing regulatory monitors and increased monitoring near susceptible populations. Monitors were both calibrated and field validated, a key component of evaluating the quality of the data produced by the community monitoring network. This paper examines the performance of a customized version of the low-cost Dylos optical particle counter used in the community air monitors compared with both PM2.5 and PM10 (particulate matter with aerodynamic diameters <2.5 and <10 µm, respectively) federal equivalent method (FEM) beta-attenuation monitors (BAMs) and federal reference method (FRM) gravimetric filters at a collocation site in the study area. A conversion equation was developed that estimates particle mass concentrations from the native Dylos particle counts, taking into account relative humidity. The R2 for converted hourly averaged Dylos mass measurements versus a PM2.5 BAM was 0.79 and that versus a PM10 BAM was 0.78. The performance of the conversion equation was evaluated at six other sites with collocated PM2.5 environmental beta-attenuation monitors (EBAMs) located throughout Imperial County. The agreement of the Dylos with the EBAMs was moderate to high (R2 = 0.35-0.81). IMPLICATIONS: The performance of low-cost air quality sensors in community networks is currently not well documented. This paper provides a methodology for quantifying the performance of a next-generation Dylos PM sensor used in the Imperial County Community Air Monitoring Network. This air quality network provides data at a much finer spatial and temporal resolution than has previously been possible with government monitoring efforts. Once calibrated and validated, these high-resolution data may provide more information on susceptible populations, assist in the identification of air pollution hotspots, and increase community awareness of air pollution.