Chon-Lin Lee

Environmentally persistent free radicals (EPFRs) and polycyclic aromatic hydrocarbons (PAHs) are persistent pollutants in atmospheric particulate matter that are detrimental to human health. This study collected atmospheric particulate matter during and after the spring festival travel season in Tainan, Taiwan, from various locations and analyzed the carbon composition and PAH isomeric ratios to identify the sources. In this study, EPFR concentrations were measured using electron paramagnetic resonance spectroscopy, with the highest concentration found to be 3.04 × 10(12) spins/m³. EPFRs contained predominantly oxygen-centered radicals in PM2.5, which are mainly existed in PM1. The results show that EPFR concentrations on PM, measured per unit volume (spins/m³) or mass (spins/g), were highest during the spring festival travel season. The daily inhalation exposure to the sum of EPFRs and PAHs in PM2.5 was estimated to be equivalent to inhaling 0.11–0.15 cigarette tar EPFRs per day. This report is the first to document EPFRs in environmental atmospheric particulate matters in Taiwan, which has significantly contributed to local air pollution control and reduced exposure risks to public health in Tainan.

Background: Adult asthma is phenotypically heterogeneous with unclear aetiology. We aimed to evaluate the potential contribution of environmental exposure and its ensuing response to asthma and its heterogeneity.Methods: Environmental risk was evaluated by assessing the records of National Health Insurance Research Database (NHIRD) and residence-based air pollution (particulate matter with diameter less than 2.5 micrometers (PM_2.5) and PM_2.5-bound polycyclic aromatic hydrocarbons (PAHs)), integrating biomonitoring analysis of environmental pollutants, inflammatory markers and sphingolipid metabolites in case–control populations with mass spectrometry and ELISA. Phenotypic clustering was evaluated by t-distributed stochastic neighbor embedding (t-SNE) integrating 18 clinical and demographic variables.Findings: In the NHIRD dataset, modest increase in the relative risk with time-lag effect for emergency (N=209 837) and outpatient visits (N=638 538) was observed with increasing levels of PM_2.5and PAHs. Biomonitoring analysis revealed a panel of metals and organic pollutants, particularly metal Ni and PAH, posing a significant risk for current asthma (ORs=1.28–3.48) and its severity, correlating with the level of oxidative stress markers, notably Nε-(hexanoyl)-lysine (r=0.108–0.311, p2.5exposure. Further, levels of circulating sphingosine-1-phosphate and ceramide-1-phosphate were found to discriminate asthma (p<0.001 and p<0.05, respectively), correlating with the levels of PAH (r=0.196, p<0.01) and metal exposure (r=0.202–0.323, p<0.05), respectively, and both correlating with circulating inflammatory markers (r=0.186–0.427, p<0.01). Analysis of six phenotypic clusters and those cases with comorbid type 2 diabetes mellitus (T2DM) revealed cluster-selective environmental risks and biosignatures.Interpretation: These results suggest the potential contribution of environmental factors from multiple sources, their ensuing oxidative stress and sphingolipid remodeling to adult asthma and its phenotypic heterogeneity.

Marine plastic debris is an environmental problem, and its degradation into microplastics (1-5000 μm) introduces them into the food chain. In this study, small polyoxymethylene (global production ~3000 Tg per year) pellets were exposed in terrestrial and simulated marine environments to heat and light, resulting in cracking during decay with increasing IR absorption (OH-bonds). Furthermore, sunlight over three years reduced pellet mass and diameter (~10% and ~40%), initially yielding 100-300 μm fragments. Changes under UV irradiation were smaller as it could not penetrate into particle interiors. Characteristic spacing of surface striations (100-300 µm) initiated radial cracks to pellet interiors, and breakdown ultimately meant 95% of particles were <300 µm, which are potentially incorporated in marine turbidites.

Considered that human activities mostly occur below building heights, the objective of this study was to investigate the temporal variations of fine particular matter (PM_2.5)-associated polycyclic aromatic hydrocarbons (PAHs) and benzo[a]pyrene-equivalent (BaP_eq) concentrations at four different elevations (6.1, 12.4, 18.4, and 27.1 m) in Kaohsiung City, the largest industrial city of southern Taiwan. Temperature variation was critical for the PM_2.5-associated PAH concentrations, which were dominated by benzo[g,h,i]perylene (0.27 ± 0.04 ng m⁻³ and 24.43% of the total concentration) and other high molecular weight (HMW) species. The PM_2.5-associated BaP_eq was dominated by 5-ring PAH (36.09%). The PM_2.5-associated PAH and BaP_eq concentrations at all elevations were significantly increased in winter. In the night, the correlations between the PM_2.5-associated PAH concentrations and atmospheric temperatures became negatively stronger, notably at lower elevations (r = − 0.73 ~ − 0.86), whereas the BaP_eq during daytime and nighttime were not changed significantly in most months. The PAHs analysis with different PM sizes demonstrated the importance of smaller particles such as PM_2.5. The meteorological variation was more important than elevation to influence the low-elevation PM_2.5-associated PAH and BaP_eq concentrations in an urban area like Kaohsiung City, as the two concentrations were dominated by the PAHs with HMWs and those 5-ring species, respectively.

Epidemiological studies have suggested the effects of ambient fine particles (PM_2.5) on asthma, but the effects of specific components of PM_2.5 on asthma remain to be explored. Here, we studied the effect of PM_2.5-bound polycyclic aromatic hydrocarbons (PAHs) on asthma acute exacerbation. The data on daily counts of emergency room visits (ERVs) were obtained from Wan Fang Medical Center, Taipei, Taiwan, from 2012 to 2015. The daily concentrations of PM_2.5 and pollutant gases were obtained from a local air quality monitoring station. The levels of PM_2.5-bound PAH were estimated by an established grid-scale model. Relative risks for ERVs as the increase in the level of ambient pollutants were calculated by using a generalized additive model of Poisson regression. In the present study, we observed statistically significant positive associations between PM_2.5 and asthma ERVs for all age groups. PM_2.5-bound PAH was also associated with asthma ERVs for all age groups. In the adult subgroup analysis, there was a significant association between PM_2.5-bound PAH and asthma ERVs at lags 1 and 2 (RR 1.289, 95% CI 1.050–1.582 and RR 1.242, 95% CI 1.039–1.485). The impacts of air pollution on the risk of pediatric asthma ERV were found to be significant for PM_2.5 at lag day 0 (RR 1.310, 95% CI 1.069–1.606). Moreover, pediatric asthma ERVs were significantly associated with the levels of PM_2.5-bound PAH at lag 1 and 2 days (RR 1.576, 95% CI 1.371–1.810 and RR 1.426, 95% CI 1.265–1.607). The study provides evidence that PM_2.5-bound PAHs were associated with an increased risk of asthma attacks. Our data further suggested that traffic exhaust is a primary source of PM_2.5-bound PAHs.