Christopher D. Simpson

Introduction: With the expansion of the U. S. legal cannabis market, there is increased awareness of health and safety concerns in the cannabis industry. Recent evidence suggests a growing burden of health symptoms in cannabis production workers, who may be exposed to toxic agents, including respiratory irritants and allergic sensitizers, during their job activities. Swift action is warranted to protect this expanding workforce by characterizing and controlling airborne exposures during cannabis production. Methods: To help address these concerns, we developed a local exhaust ventilation (LEV) system with a partially-enclosed hood to control particle and terpene emissions during cannabis processing activities using a minimum efficiency reporting value (MERV)-13 filter (particles) and an activated charcoal filter (terpenes). Inhalable particulate matter (PM) and total terpene air concentrations were compared with and without the LEV system across three separate paired trials during whole flower grinding and automated pre-roll joint filling. Results: On average, the LEV system reduced inhalable PM concentrations by 95% during whole flower grinding and 83% during pre-roll joint filling. The LEV system was similarly effective in controlling total terpenes, reducing concentrations to below the limit of detection (LOD) during whole flower grinding. Discussion: To date, this is the first study to evaluate the efficacy of LEV as an exposure control during cannabis processing. These preliminary results suggest that the partially-enclosed hood LEV system is an effective exposure control for cannabis processing activities. Findings from this study can guide future industrial hygiene interventions that protect cannabis workers from potentially harmful exposures.

Diesel exhaust (DE) is a major traffic-related pollutant linked to adverse health outcomes, but existing methods for estimating indoor DE exposure are not validated. DE exposure indicators such as black carbon (BC), NOx, and PM_2.5 are not sufficiently specific to diesel sources. 1-Nitropyrene (1-NP), an NPAH preferentially formed during diesel combustion, has rarely been studied as an indoor exposure indicator. We measured 1-NP and isomeric NPAHs (2-nitropyrene, 2-nitrofluoranthene) in indoor air and house dust from 40 homes in the eastern San Francisco Bay Area, CA, and conducted continuous indoor BC monitoring. We assessed 1-NP’s utility as a DE exposure indicator using summary statistics, diagnostic NPAH ratios, correlations with monitored pollutants, and single-predictor mixed-effects models relating 1-NP to spatial DE predictors. 1-NP was frequently detected in air (74%) and dust (97%), with median concentrations of 0.42 pg/m³ (IQR 0.32–0.54) and 340 pg/g (IQR 190–620), respectively. Air and dust 1-NP were moderately correlated (r = 0.40, p = 0.02), as was BC with 1-NP (air r = 0.38, dust r = 0.47; p < 0.01). Diagnostic ratios (2-NFl:1-NP < 5) indicated dominant primary emission sources. Dust 1-NP showed numerous significant associations with spatial DE predictors, while air 1-NP showed fewer. Overall, 1-NP shows promise as a diesel-specific indoor exposure indicator. Future studies with larger, geographically diverse cohorts are needed to further validate this metric.

Diesel exhaust (DE) is a major traffic-related pollutant linked to adverse health outcomes, but existing methods for estimating indoor DE exposure fall short, as common surrogates like black carbon (BC), NOx, and PM2.5 are not sufficiently specific to diesel sources. 1-Nitropyrene (1-NP), a nitro-PAH preferentially formed during diesel combustion, has rarely been studied as an indoor exposure indicator. We measured 1-NP and isomeric nitro-PAHs (2-nitropyrene, 2-nitrofluoranthene) in indoor air and house dust from 40 homes in the eastern San Francisco Bay Area, CA, across two sampling events, alongside continuous indoor BC monitoring. We assessed 1-NP’s utility as a DE proxy using summary statistics, diagnostic nitro-PAH ratios, correlations with monitored pollutants, and single-predictor mixed-effects models relating 1-NP to spatial DE predictors. 1-NP was frequently detected in air (74%) and dust (97%), with median concentrations of 0.42 pg/m³ (IQR 0.32 - 0.54) and 340 pg/g (IQR 190 - 620), respectively. Air and dust 1-NP were moderately correlated (r=0.40, p = 0.02), as was BC with 1-NP (air r=0.38, dust r=0.47; p<0.01). Diagnostic ratios (2-NFl:1-NP <5) indicated dominant primary emission sources. Dust 1-NP showed numerous significant associations with spatial DE predictors, while air 1-NP showed fewer. Overall, 1-NP shows promise as a diesel-specific indoor exposure proxy integrating longer-term exposure and aligning with spatial DE predictors.

Objective: The aim of the study was to evaluate respiratory and allergic health symptoms and sensitization to cannabis in cannabis workers while controlling for recreational cannabis use. Methods: We compared allergic and respiratory symptoms, lung function, and airway inflammation among cannabis workers ( n = 42) and recreational cannabis users ( n = 20) and nonusers ( n = 20) with no occupational exposure. Results: In multivariable regressions adjusted for recreational cannabis use, cannabis workers trended toward increased airway inflammation and decreased pulmonary function when compared to nonworkers. Compared to nonworkers, cannabis workers exhibited increased odds of cannabis sensitization on skin prick test (odds ratio, 9.5; 95% confidence interval, 1.38 to 193; P = 0.05) and reported a higher prevalence of allergic symptoms (odds ratio, 3.7; 95% confidence interval, 0.91, 16.9; P = 0.07). Conclusions: Our findings suggest that occupational exposures contribute to the respiratory and allergic effects seen in cannabis workers, regardless of recreational cannabis use.

Prenatal exposure to polycyclic aromatic hydrocarbons (PAHs) has been linked to lower birth weight (BW) and shorter gestational age (GA) at delivery. Most research has focused on populations in high-income countries, leaving low- and middle-income countries (LMICs) understudied. We examined associations between pregnancy urinary PAH metabolites and birth outcomes in a prospective cohort in Nairobi, Kenya. The study population was drawn from women and their newborn babies enrolled in a pregnancy cohort in Nairobi, Kenya. Third-trimester urinary mono-hydroxylated PAH metabolites (OH-PAH) were measured and infant BW and GA were ascertained using medical record abstraction and self-report; BW-for-GA z-scores were computed. Linear and modified Poisson regression models were used to estimate the effects of five OH-PAHs on birth outcomes; Weighted Quantile Sum regression was used to explore OH-PAH mixture effects. Among 353 mother-infant pairs, the median infant BW was 3.2 kg and10.7% were born preterm. All OH- PAH metabolites were present in urine of >99% of mothers. Individual OH-PAH concentrations were not associated with BW or BW-for-GA z-scores. One metabolite, 2-hydroxyphenanthrene, was associated with shortened gestation (RR = -1.6 day per doubling in concentration, 95% confidence interval: -3.1, - 0.1). This association was attenuated after adjusting for self-reported exposure to household fuel and outdoor combustion and was strengthened among female infants, but not male infants, in sex-stratified analyses. Other metabolites and the OH-PAH mixture were not associated with birth outcomes. Our findings suggest that exposure to 2-hydroxyphenanthrene may have a modest adverse effect on pregnancy duration, with potential sex-specific differences in association. No associations were observed for markers of fetal growth. These results highlight need for further studies on sex-specific vulnerabilities and the role of environmental co-exposures in impacting birth outcomes in LMICs.

Wood smoke exposure poses significant health risks, particularly in occupations such as firefighting, where short-term exposure to high levels of pollutants is common. The biomonitoring of wood smoke-associated biomarkers is crucial for assessing human exposure. S-phenylmercapturic acid (S-PMA), a key metabolite of benzene, has been widely used as a reliable biomarker for this purpose. However, current S-PMA detection methods lack the speed, portability, and user-friendliness required for widespread, on-site applications. In this study, we propose a novel detection system that integrates mesoporous Pd@Pt nanoparticle-mediated lateral flow immunoassay (LFIA) with a 3D-printed smartphone-based reader for detecting S-PMA. Performance testing with S-PMA in phosphate-buffered saline and spiked urine samples yielded limits of detection of 0.5 ng/mL and 2.5 ng/mL, respectively. The use of mesoporous Pd@Pt nanoparticles as signal amplifiers for LFIA, along with the integration of a 3D-printed device for accurate image acquisition, significantly enhanced the system's sensitivity, achieving detection limits well below the threshold recommended by the American Conference of Governmental and Industrial Hygienists. With remarkable stability and reproducibility, our method provides a noninvasive, highly sensitive, rapid, portable, low-cost, and user-friendly solution for the on-site assessment of wood smoke exposure in occupational settings, laying the foundation for future innovations in real-time environmental exposure monitoring.

Recently, the misuse of fentanyl and methamphetamine has increased in the United States. These drugs can be consumed via smoking a powder, which can subsequently contaminate air and surfaces with drug residue. With limited access to safe consumption sites, this misuse often occurs in public spaces such as public transit, leading to potential secondhand exposures among transit operators and riders. In the Pacific Northwest, transit operators have reported acute health symptoms and safety concerns regarding these drug exposures. Researchers conducted an exposure assessment, sampling air and surfaces for fentanyl and methamphetamine. A total of 78 air samples and 89 surface samples were collected on 11 buses and 19 train cars from four transit agencies in the Pacific Northwest. Fentanyl was detected above the limit of quantification (LOQ) in 25% of air samples (range of concentrations > LOQ: 0.002 to 0.14 µg/m³) and 38% of surface samples (range of concentrations > LOQ: 0.011 to 0.47 ng/cm²), while methamphetamine was detected in 100% of air samples (range: 0.003 to 2.32 µg/m³) and 98% of surface samples (range of concentrations > LOQ: 0.016 to 6.86 ng/cm²) The highest fentanyl air sample (0.14 µg/m³) was collected in the passenger area of a train for 4 hr, and would exceed the ACGIH^® 8-hr TWA TLV^® of 0.1 µg/m³ if conditions remained the same for the unsampled period. No surface samples exceed the ACGIH fentanyl surface level TLV (10 ng/cm²). The prevalence of fentanyl and methamphetamine on public transit highlights the need to protect transit operators from secondhand exposure and from the stress of witnessing and responding to smoking events. Future work is needed to evaluate the utility of engineering and administrative controls such as ventilation and cleaning upgrades in reducing exposures on transit, as well as the utility of training and increased workplace support for operators in addressing their health and well-being after observing or responding to drug use events.