Estrella Herrera-Molina

Air quality in the San Joaquin Valley (SJV) ranks among the worst in the US. Exposures to traffic-related air pollutants have been associated with pediatric health complications, and few studies have investigated respiratory complications in relation to short-term exposures to PM less than 2.5 microns in diameter (PM_2.5) in the SJV. We used Bayesian Poisson spatiotemporal conditional autoregressive models to analyze the association between PM_2.5 and pediatric respiratory emergency department (ED) visits in Fresno County, California. Additional analyses stratified respiratory outcomes by sex and age group. Weekly ambient PM_2.5 levels were estimated for each zip code using community science and regulatory air monitors. Weekly residential zip code counts of respiratory ED visits were provided by Fresno County Department of Public Health and Valley Children’s Hospital from 2 April 2022 to 31 December 2024. A ten-fold increase in PM_2.5 was associated with increased asthma ED visits among females (Relative Risk (RR):1.15; 95% Credible Interval (CrI):1.01, 1.32) and children aged 0 to 4 (RR:1.18; 95% CrI:1.03, 1.34) and other chronic respiratory conditions among males (RR:1.93; 95% CrI:1.19, 3.16) and ages 10 to 14 (RR:2.90; 95% CrI:1.32, 6.30). Findings suggest that efforts to better assess and reduce pollution exposures will improve public health in the SJV.

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 categories. The diagnoses of neurodegenerative, respiratory, and associated diseases were also significantly associated with DE in our earlier studies in Lubbock and El Paso counties. 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. Therefore, 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.

Air quality in the San Joaquin Valley (SJV) often fails to meet Environmental Protection (EPA) Standards for particulate matter (PM) ≤ 2.5 microns. The San Joaquin Valley Center for Air Injustice Reduction (SJV-CAIR) at the University of California, Merced, partnered with local community-based organizations to expand networks of low-cost air quality monitors (PurpleAir, PA-II) in Fresno County to increase community air monitoring to better characterize air pollution trends and spatial variability. In this study, we compared community and regulatory air pollution monitoring using PM_2.5 data from the SJV-CAIR network in Fresno County during June–July 2023. Measurements from community monitors identified locations across the county that may episodically exceed National Ambient Air Quality Standards (NAAQS) compared with regulatory monitors, while providing similar concentration estimates. Our study also compared characterization of spatial variability in PM exposure using interpolation maps with only regulatory monitors and the enhanced community monitoring network. These analyses identified four weeks with increased PM_2.5 concentrations in some locations that were not identified by regulatory monitors. These findings indicate that low-cost community sensors can be an effective tool for supplementing regulatory monitoring to provide localized PM_2.5 exposure information to residents and, importantly, identify high-risk areas that warrant ongoing assessment using approved regulatory monitors.

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.