Air and water quality at a concentrated animal feeding operation (CAFO) in Eastern North Carolina that uses a covered lagoon and anaerobic digester was evaluated for 2 weeks in August 2020. Real-time PM₂.₅ mass concentrations were determined using a reference ADR-1500 nephelometer and high-frequency measurements of dissolved inorganic nitrogen (DIN) were evaluated using autonomously logging sensors. Air and water quality parameters were assessed before, during and after wastewater from the lagoon was irrigated onto adjacent spray fields. Reference measurements were conducted alongside a HOBO weather station to collect real-time wind speed and direction, temperature, and humidity measurements. PM₂.₅ concentrations varied between 0 and 159 μg/m³ with an average concentration of 11 μg/m³, below EPA standard for secondary aerosols of 15 μg/m³. Higher PM₂.₅ concentrations were observed when wind originated from swine barns but not from covered lagoons. Water quality data showed that DIN concentrations downgradient from the CAFO were elevated relative to upstream concentrations. A groundwater seep that drains a spray field contained the highest average DIN concentration (31.0 ± 12.8 mg L⁻¹), which was 25 times greater than upstream DIN concentrations (1.2 ± 0.8 mg L⁻¹). Average DIN concentration at the downstream station was lower than the seep concentration (8.6 ± 16.2 mg L⁻¹), but approximately 8 times greater than upstream. Air quality data show that the lagoon cover was effective at mitigating air quality degradation, whereas DIN concentrations in water were similar to previous studies on CAFOs using open lagoons. In addition, air and water quality parameters were significantly (p < 0.001) higher after irrigation, indicating possible influence due to ammonia and nitrate elevation. Additional research is needed to compare high-frequency data collected from swine CAFOs using capped and uncapped lagoon systems to better understand spatiotemporal air and water quality trends of this practice.

Polycyclic aromatic hydrocarbons (PAHs) in soil can be recalcitrant to solvent extraction after aging. We showed in this study that mixing a small amount of water in the extracting solvent during microwave-assisted extraction (MAE) can release recalcitrant PAHs, resulting in significant improvement in the analyzed concentrations. The improvement factor (F) for the total of 16 priority PAHs (∑PAH16) listed by the United States Environmental Protection Agency was 1.44–1.55 for field soils. By comparing the F values for different soil organic components, we demonstrated that the recalcitrant PAHs were primarily associated with biochar, humic acid (HA), and humin (HM), with the F values for ∑PAH16 of 1.94, 6.62, and 4.59, respectively. The results showed that the recalcitrant PAHs comprised a sequestered fraction and a desorption-limited fraction. NMR spectra showed that water worked alone at elevated temperature to promote hydrolysis of biochar and destroy the macromolecular structure, thus causing the release of the otherwise sequestered PAHs during MAE. The substantial reduction in F values for HA and HM after demineralization indicated sequestration of PAHs in organic-mineral complexes, which can be destroyed by hot water treatment. The release of the sequestered fraction was nonselective and independent of compound hydrophobicity. In comparison, the release of the desorption-limited fraction was positively affected by the hydrophobicity of PAHs and was facilitated by the presence of water in the extracting solvent. The results of this study provide important insights into the sequestration and release of recalcitrant PAHs in soil.

There is increasing concern about the environmental behaviors of microplastics (MPs), in particular fine MPs (FMPs), such as their concentrations, sources, size distributions, and fragmentation by weathering in waters. However, there is little information about size distributions of MP polymer types and their relationships to their sources. Here, we analyzed concentrations, compositions, and size distributions of 18 polymer types of MPs of >20 μm by micro-Fourier transform infrared spectroscopy with a novel pretreatment method in surface waters at five sites from the headwaters to the mouth of a Japanese river, and in influent and effluent from a sewage treatment plant (STP). The microplastic concentrations ranged from 300 to 1240 particles/m³ in surface waters. Cluster analysis identified two primary sources of MPs: residential wastewater at the headwater site and non-point sources from urban areas at downstream sites; concentrations of chemical contaminants from STPs were much higher at the downstream sites. The median particle sizes (D₅₀) of MPs increased in urban areas at the downstream sites and were larger than those in influent and effluent. These results imply the release of larger MPs from non-point sources in urban areas. The size distributions of each polymer and all MPs could be fitted significantly to the Weibull distribution function. Values of D₅₀, shape parameters, and scale parameters estimated from the functions were useful indicators for evaluating size distributions in detail. A significant positive correlation of D₅₀ with the tensile strengths of virgin polymers among 13 dominant polymers detected in the surface water suggests that the fragmentation properties of each polymer are influenced by its physical strength. Multidimensional analysis with concentrations, polymeric compositions, and size distributions of MPs, including FMPs, could provide useful information about their sources and their environmental behaviors.

Breast milk is a unique biological sample that reflects the exposure levels of both lactating mothers and infants. The exposure levels of BPA due to breast milk consumption for infants can be estimated easily, but the method to estimate the total daily intake (TDI) of lactating mothers from breast milk has not yet been established. In this study, BPA concentrations were detected in breast milk samples from 149 lactating mothers from Hunan, China. The median concentration of BPA in breast milk was 0.053 μg/L with a range of 0.001–2.535 μg/L, and a temporal decline trend was found for BPA concentrations in breast milk (p < 0.05). The median intake of BPA via breast milk was 26.8 ng/kg bw/day for 0-3-month-old infants and 7.0 ng/kg bw/day for 4-12-month-old infants. Based on the predicted concentrations of BPA in urine and blood via the conversion coefficients from breast milk, the TDIs of lactating mothers were estimated. The TDIs estimated from the simulated urine concentration were 84.0 ± 175.2 ng/kg bw/day for 0-3-month-old infants' mothers and 36.9 ± 80.8 ng/kg bw/day for 4-12-month-old infants' mothers. The dietary daily intakes estimated from the simulated blood concentration were 579.6 ± 370.8 ng/kg bw/day for 0-3-month-old infants' mothers and 280.1 ± 195.2 ng/kg bw/day for 4-12-month-old infants’ mothers. When assuming the dietary daily intakes in Hunan of the fifth total diet study (TDS) as the “true” total dietary intake of our population, the contribution of diet was estimated to be 63.7%, which suggested that non-dietary BPA exposure may be underestimated.

Swift degradation of the coral reef ecosystems urges the need to identify the reef decline drivers. Due to their widespread use, bioaccumulative and toxic characteristics, chlorinated organic compounds, such as chlorinated paraffins (CPs), are regarded as specific pollutants of concern. Yet little is known about the occurrence of CPs in the coral reef ecosystems. This study focuses on the short-chain chlorinated paraffins (SCCPs) and medium-chain chlorinated paraffins (MCCPs). Their distribution and congener pattern were investigated in the water-SPM-sediment system and in the corals of the Larak coral reef for the first time. Chlorinated paraffins were detected in all the coral species. Their total loadings ranged from 42.1 to 178 ng g⁻¹ dw in coral tissue, from 6.0 to 144 ng g⁻¹dw in the skeleton, and from 55.0 to 240 ng g⁻¹dw in zooxanthellae. Soft corals were found to accumulate more CPs than Scleractinian corals. Zooxanthellae and mucus accumulated more CPs than tissue and skeleton. In most cases, congener group patterns were dominated by C₁₃ (for SCCPs) and C₁₇ (MCCPs) groups, respectively. The congener patterns of CPs altered to some extent between mucus and the remaining coral compartments. High loadings of CPs were detected in the skeleton of the bleached corals. Moreover, a significant negative correlation between the levels of CPs and the symbiodinium density was observed.

Tropospheric ozone is a dangerous atmospheric pollutant for forest ecosystems when it penetrates stomata. Thresholds for ozone-risk assessment are based on accumulated stomatal ozone fluxes such as the Phytotoxic Ozone Dose (POD). In order to identify the effect of ozone on a Holm oak forest in central Italy, four flux-based ozone impact response functions were implemented and tested in a multi-layer canopy model AIRTREE and evaluated against Gross Primary Productivity (GPP) obtained from observations of Eddy Covariance fluxes of CO₂. To evaluate if a clear phytotoxic threshold exists and if it changes during the year, six different detoxifying thresholds ranging between 0 and 5 nmol O₃ m⁻² s⁻¹ were tested.The use of species-specific rather than more general response functions based on plant functional types (PFT) increased model accuracy (RMSE reduced by up to 8.5%). In the case of linear response functions, a threshold of 1 nmol m⁻² s⁻² produced the best results for simulations of the whole year, although the tolerance to ozone changed seasonally, with higher tolerance (5 nmol m⁻² s⁻¹ or no ozone impact) for Winter and Spring and lower thresholds in Summer and Fall (0–1 nmol m⁻² s⁻¹). A “dynamic threshold” obtained by extracting the best daily threshold values from a range of different simulations helped reduce model overestimation of GPP by 213 g C m⁻² y⁻¹ and reduce RMSE up to 7.7%. Finally, a nonlinear ozone correction based on manipulative experiments produced the best results when no detoxifying threshold was applied (0 nmol O₃ m⁻² s⁻¹), suggesting that nonlinear functions fully account for ozone detoxification. The evidence of seasonal changes in ozone tolerance points to the need for seasonal thresholds to predict ozone damage and highlights the importance of performing more species-specific manipulative experiments to derive response functions for a broad range of plant species.

Land use regression modeling is a common method for assessing exposure to ambient pollutants, yet it suffers from very coarse temporal resolution. Wireless distributed sensor networks (WDSN) is a promising technology that can provide extremely high spatiotemporal pollutant patterns but is known to suffer from several limitations that put into question its data reliability. This study examines the advantages of fusing data from these two methods and obtaining high spatiotemporally-resolved product that can be used for exposure assessment. We demonstrate this approach by estimating nitrogen dioxide (NO₂) concentrations at a sub-urban scale, with the study area limited by the deployment of the WDSN nodes. Specifically, hourly-resolved fused-data estimates were obtained by combining a stationary traffic-based land use regression (LUR) model with observations (15 min sampling frequency) made by an array of low-cost sensor nodes, with the sensors’ readings mapped over the whole study area. Data fusion was performed by merging the two independent information products using a fuzzy logic approach. The performance of the fused product was examined against reference hourly observations at four air quality monitoring (AQM) stations situated within the study area, with the AQM data not used for the development of any of the underlying information layers. The mean hourly RMSE between the fused data product and the AQM records was 9.3 ppb, smaller than the RMSE of the two base products independently (LUR: 14.87 ppb, WDSN: 10.45 ppb). The normalized Moran’s I of the fused product indicates that the data-fusion product reveals more realistic spatial patterns than those of the base products. The fused NO₂ concentration product shows considerable spatial variability relative to that evident by interpolation of both the WDSN records and the AQM stations data, with significant non-random patterns in 74% of the study period.

Filters installed in the heating, ventilation, and air-conditioning (HVAC) systems can serve as air-cleaning and sampling devices for indoor particles. The purpose of this article is to evaluate these dual roles. An occupied home with a central HVAC system equipped with a Minimum Efficiency Reporting Value (MERV, from ASHRAE Standard 52.2) 11 filter was monitored for six weeks. Weekly airborne gravimetric and real-time sampling was performed to measure the particle size distribution and the concentration of total suspended particles (TSP), PM₁₀, PM₂.₅, PM₁, and 12 trace metals. The weekly system runtimes were intentionally changed to provide a wide range of weekly filtration volumes. The quantitative filter forensics (QFF) concentrations of particulate matter (PM) and trace metals were calculated using the analysis of the dust collected on the HVAC filter, the filtration volume, and filter in-situ efficiency. The results indicated that filtration was not influential to remove PM and trace metals as the concentrations during the weeks with continuous HVAC operation were not consistently lower than those during the other weeks. This suggests the dominance of other particle and trace metal source and loss mechanisms weakens the influence of filtration in this home. The QFF evaluation results indicated that the concentration of TSP and over half of the tested trace metals (e.g., Pb, Cd, Ni, V, Sb, K, and Sr) could be estimated by QFF within a factor of two when compared to airborne sampling results. PM₁₀, PM₂.₅, and PM₁ concentrations were significantly underestimated by QFF potentially due to the limitations of size distribution analysis by a laser diffraction particle sizer (LDPS) for the detection of <1 μm particles. Overall, while QFF was promising for TSP and some trace metals, improvement in size distribution analysis could extend the application of QFF for airborne sampling.

Stillbirth has a great impact on contemporary and future generations. Increasing evidence show that ambient air pollution exposure is associated with stillbirth. However, previous studies showed inconsistent findings. To clarify the effect of maternal air pollution exposure on stillbirth, we searched for studies examining the associations between air pollutants, including particulate matter (diameter ≤ 2.5 μm [PM₂.₅] and ≤10 μm [PM₁₀]) and gaseous pollutants (sulfur dioxide [SO₂], nitrogen dioxide [NO₂], carbon monoxide [CO] and ozone [O₃]), and stillbirth published in PubMed, Web of Science, Embase and Cochrane Library until December 11, 2020. The pooled effect estimates and 95% confidence intervals (CI) were calculated, and the heterogeneity was evaluated using Cochran’s Q test and I² statistic. Publication bias was assessed using funnel plots and Egger’s tests. Of 7546 records, 15 eligible studies were included in this review. Results of long-term exposure showed that maternal third trimester PM₂.₅ and CO exposure (per 10 μg/m³ increment) increased the odds of stillbirth, with estimated odds ratios (ORs) of 1.094 (95% CI: 1.008–1.180) and 1.0009 (95% CI: 1.0001–1.0017), respectively. Entire pregnancy exposure to PM₂.₅ was also associated with stillbirth (OR: 1.103, 95% CI: 1.074–1.131). A 10 μg/m³ increment in O₃ in the first trimester was associated with stillbirth, and the estimated OR was 1.028 (95% CI: 1.001–1.055). Short-term exposure (on lag day 4) to O₃ was also associated with stillbirth (OR: 1.002, 95% CI: 1.001–1.004). PM₁₀, SO₂ and NO₂ exposure had no significant effects on the incidence of stillbirth. Additional well-designed cohort studies and investigations regarding potential biological mechanisms are warranted to elaborate the suggestive association that may help improve intergenerational inequality.