Evaluation of Low-Cost CO2 Sensors Using Reference Instruments and Standard Gases for Indoor Use.

CO2 monitoring is important for carbon emission evaluation. Low-cost and medium-precision sensors (LCSs) have become an exploratory direction for CO2 observation under complex emission conditions in cities. Here, we used a calibration method that improved the accuracy of SenseAir K30 CO2 sensors from ±30 ppm to 0.7-4.0 ppm for a CO2-monitoring instrument named the SENSE-IAP, which has been used in several cities, such as in Beijing, Jinan, Fuzhou, Hangzhou, and Wuhan, in China since 2017. We conducted monthly to yearly synchronous observations using the SENSE-IAP along with reference instruments (Picarro) and standard gas to evaluate the performance of the LCSs for indoor use with relatively stable environments. The results show that the precision and accuracy of the SENSE-IAP compared to the standard gases were rather good in relatively stable indoor environments, with the short-term (daily scale) biases ranging from -0.9 to 0.2 ppm, the root mean square errors (RMSE) ranging from 0.7 to 1.6 ppm, the long-term (monthly scale) bias ranging from -1.6 to 0.5 ppm, and the RMSE ranging from 1.3 to 3.2 ppm. The accuracy of the synchronous observations with Picarro was in the same magnitude, with an RMSE of 2.0-3.0 ppm. According to our evaluation, standard instruments or reliable standard gases can be used as a reference to improve the accuracy of the SENSE-IAP. If calibrated daily using standard gases, the bias of the SENSE-IAP can be maintained within 1.0 ppm. If the standard gases are hard to access frequently, we recommend a calibration frequency of at least three months to maintain an accuracy within 3 ppm.

Distinct and common mechanisms of cross-model semantic conflict and response conflict in an auditory relevant task.

The mechanisms of semantic conflict and response conflict in the Stroop task have mainly been investigated in the visual modality. However, the understanding of these mechanisms in cross-modal modalities remains limited. In this electroencephalography (EEG) study, an audiovisual 2-1 mapping Stroop task was utilized to investigate whether distinct and/or common neural mechanisms underlie cross-modal semantic conflict and response conflict. The response time data showed significant effects on both cross-modal semantic and response conflicts. Interestingly, the magnitude of semantic conflict was found to be smaller in the fast response time bins than in the slow response time bins, whereas no such difference was observed for response conflict. The EEG data demonstrated that cross-modal semantic conflict specifically increased the N450 amplitude. However, cross-modal response conflict specifically enhanced theta band power and theta phase synchronization between the medial frontal cortex (MFC) and lateral prefrontal electrodes as well as between the MFC and motor electrodes. In addition, both cross-modal semantic conflict and response conflict led to a decrease in P3 amplitude. Taken together, these findings provide cross-modal evidence for domain-specific mechanism in conflict detection and suggest both domain-specific and domain-general mechanisms exist in conflict resolution.

Distinct mechanisms underlying cross-modal semantic conflict and response conflict processing.

Interference from task-irrelevant stimuli can occur during the semantic and response processing stages. Previous studies have shown both common and distinct mechanisms underlying semantic conflict processing and response conflict processing in the visual domain. However, it remains unclear whether common and/or distinct mechanisms are involved in semantic conflict processing and response conflict processing in the cross-modal domain. Therefore, the present electroencephalography study adopted an audiovisual 2-1 mapping Stroop task to investigate whether common and/or distinct mechanisms underlie semantic conflict and response conflict. Behaviorally, significant cross-modal semantic conflict and significant cross-modal response conflict were observed. Electroencephalography results revealed that the frontal N2 amplitude and theta power increased only in the semantic conflict condition, while the parietal N450 amplitude increased only in the response conflict condition. These findings indicated that distinct neural mechanisms were involved in cross-modal semantic conflict and response conflict processing, supporting the domain-specific cognitive control mechanisms from a cross-modal multistage conflict processing perspective.

Drying Process of HPMC-Based Hard Capsules: Visual Experiment and Mathematical Modeling.

Using plant-based polysaccharide gels to produce hard capsules is a novel application of this technology in the medicinal field, which has garnered significant attention. However, the current manufacturing technology, particularly the drying process, limits its industrialization. The work herein employed an advanced measuring technique and a modified mathematical model to get more insight into the drying process of the capsule. Low field magnetic resonance imaging (LF-MRI) technique is adopted to reveal the distribution of moisture content in the capsule during drying. Furthermore, a modified mathematical model is developed by considering the dynamic variation of the effective moisture diffusivity (Deff) according to Fick's second law, which enables accurate prediction of the moisture content of the capsule with a prediction accuracy of ±15%. The predicted Deff ranges from 3 × 10-10 to 7 × 10-10 m2·s-1, which has an irregular variation with a time extension. Moreover, as temperature increases or relative humidity decreases, there is an increased acceleration of moisture diffusion. The work provides a fundamental understanding of the drying process of the plant-based polysaccharide gel, which is crucial for enhancing the industrial preparation of the HPMC-based hard capsules.

Estimate of hydrochlorofluorocarbon emissions during 2011-2018 in the Yangtze River Delta, China.

Hydrochlorofluorocarbons (HCFCs) are used as temporary substitutes for chlorofluorocarbons and other ozone-depleting substances because they have reduced ozone depletion and global warming potentials. The consumption and production of HCFCs are regulated via the Montreal Protocol and its amendments till 2013, with a complete phase-out being scheduled by 2030 for Article 5 parties (developing countries). To better understand the characteristics and emissions of HCFCs in the Yangtze River Delta (YRD), which is the largest metropolitan area in China, weekly flask samples were collected at the Lin'an regional background station located in the YRD from 2011 to 2018 and measured for four HCFCs (HCFC-22, HCFC-141b, HCFC-142b, and HCFC-124). The HCFC-132b and HCFC-133a measurements began in 2018. The ambient mixing ratios of the HCFCs exhibited higher concentrations and larger variabilities than those at the Shangri-la regional background station at similar latitudes in southwest China. The HCFC emissions in the YRD were estimated based on the tracer ratio method using CO and HFC-134a as tracers, and were comparable within the uncertainties. Our results are generally consistent with previous estimates obtained using top-down approaches. HCFC-22 and HCFC-141b contributed 52% ± 23% and 41% ± 24% of the total ODP-weighted (CFC-11-equivalent) HCFC emissions from the YRD, respectively, whereas HCFC-22 contributed the most (83% ± 36%) to the total CO2-equivalent HCFC emissions from the YRD. The cumulative ODP-weighted and CO2-equivalent emissions of HCFCs from the YRD accounted for 25% ± 15% and 20% ± 11% of the national corresponding totals, respectively, for 2011-2017. The HCFC-141b emissions from the YRD contributed approximately half of the total Chinese emissions. HCFC-133a emissions in the YRD accounted for approximately one-fifth of the global total in 2018. Thus, the YRD is an important contributor of HCFC emissions on national and global scales.

The congruency sequence effect is modulated by the similarity of conflicts.

The congruence effect can be modulated by adjacent conflict conditions, producing the congruency sequence effect (CSE). However, many boundary conditions prevent the transfer of the cross-conflict CSE. A consensus has been achieved that the CSE reflects both top-down control and bottom-up associative learning, but neither perspective could perfectly interpret the various boundary conditions. Their imperfections recently inspired an integrative learning account of cognitive control, which predicts that conflict similarity affects the magnitude of the cross-conflict CSE. We examined this hypothesis with the spatial Stroop-Simon paradigm by introducing a compound condition containing both the Stroop and Simon components (Experiment 1). The conflict similarity was defined by the degree of component overlap, as manipulated by the polar angle of the target arrow in Experiments 2a and 2b and by the Euclidean distance of the target arrow in Experiments 3a and 3b. Mixed-effect modeling analyses indicated that, in all experiments, the cross-conflict CSEs were positively correlated with the similarity among conflict conditions. Specifically, the compound condition with equal Stroop and Simon components generated comparable CSEs with both the Stroop and Simon conditions (Experiment 1). When the compound condition was more similar to the Stroop than the Simon condition, a trend of a larger CSE was observed between the compound conflict and the Stroop condition than between the compound conflict and the Simon condition, and vice versa (Experiments 2 and 3). Our study revealed that the continuum of the cross-conflict CSE was modulated by conflict similarity, hence supporting the integrative learning account of cognitive control. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Characteristics and source attribution of PM2.5 during 2016 G20 Summit in Hangzhou: Efficacy of radical measures to reduce source emissions.

A field campaign was conducted to study the PM2.5 and atmospheric gases and aerosol's components to evaluate the efficacy of radical measures implemented by the Chinese government to improve air quality during the 2016 G20 Summit in Hangzhou China. The lower level of PM2.5 (32.48 ± 11.03 µg/m3) observed during the control period compared to pre-control and post-control periods showed that PM2.5 was alleviated by control policies. Based on the mass concentrations of particulate components, the emissions of PM2.5 from local sources including fossil fuel, coal combustion, industry and construction were effectively reduced, but non-exhaust emission was not reduced as effectively as expected. The accumulation of SNA (SO42-, NO3-, NH4+) was observed during the control period, due to the favourable synoptic weather conditions for photochemical reactions and heterogeneous hydrolysis. Because of transboundary transport during the control period, air masses from remote areas contributed significantly to local PM2.5. Although, secondary organic carbon (OCsec) exhibited more sensitivity than primary organic carbon (OCpri) to control measures, and the increased nitrogen oxidation ratio (NOR) implied the regional transport of aged secondary aerosols to the study area. Overall, the results from various approaches revealed that local pollution sources were kept under control, indicating that the implementation of mitigation measures were helpful in improving the air quality of Hangzhou during G20 summit. To reduce ambient levels of PM2.5 further in Hangzhou, regional control policies may have to be taken so as to reduce the impact of long-range transport of air masses from inland China.

Ambient marine shipping emissions determined by vessel operation mode along the East China Sea.

Marine shipping emissions exert important air quality and climate impacts. This study characterized the ambient pollutants predominant by emissions from a variety of marine vessel types near the mid-latitude East China Sea. Two discernible primary shipping emissions were identified by factorization analysis on detailed mass spectra of organic aerosol (OA), as emissions in maneuvering and cruise, highly linked with NOx (and less oxidized OA, black carbon, BC) or CO (and more oxidized OA), respectively. Using radio-recorded quantities and activities of 3566 vessels mixed with slow and high-speed diesel engines, we found emission of NOx or BC per vessel was positively correlated with vessel speed, while CO emission peaked at moderate speed. The approach here based on vessel operation mode directly linked the vessel activities to ambient concentrations of pollutants from marine shipping emission, and may synthesize the complex vessel types in shipping emission inventory.

Characteristics, sources, and health risks of PM2.5-bound trace elements in representative areas of Northern Zhejiang Province, China.

This study aimed to characterize PM2.5-bound trace elements in Northern Zhejiang Province (NZP), one of the most economically prosperous regions in China, and assess the associated health risks for the general populations. A year-long sampling campaign was conducted at four sites representative of urban, suburban, and rural areas of NZP. The average of the sum of twenty trace elements in PM2.5 was 2.8 ± 0.4 µg m-3, dominated by K, Al, Fe, Mg, Zn, and V (>100 ng m-3). The highest total elements' concentration occurred in winter, followed by autumn, spring, and summer. Enrichment factors and principal component analysis (PCA) revealed that the major sources of trace elements in NZP were fossil fuel combustion, biomass burning, crustal dust, traffic, and industrial emissions. Elevated concentrations of certain elements reflected featured sources in different areas, e.g., V and Ni from heavy oil combustion in the port city, and Cu, Fe and Ba from traffic emissions in urban areas. Arsenic (As) represented the major non-cancer risk driver as its hazard quotient was 8.7. The cumulative cancer risk from all the carcinogenic elements was 1.7 × 10-3 in NZP, exceeding the upper limit (10-4) of the acceptable risk range. As and Cr contributed 33% and 66%, respectively, and thus were regarded as cancer risk drivers. The high health risks from PM2.5-bound elements warrant future actions to control their emissions in this region. Priorities should target industrial operations and coal combustion emissions, as informed by the risk drivers.

Modality-specific neural mechanisms of cognitive control in a Stroop-like task.

The successful resolution of ever-changing conflicting contexts requires efficient cognitive control. Previous studies have found similar neural patterns in conflict processing for different modalities using an event-related potential (ERP) approach and have concluded that cognitive control is supramodal. However, recent behavioral studies have found that conflict adaptation (a phenomenon with the reduction of congruency effect in the current trial after an incongruent trial as compared with a congruent trial) could not transfer across visual and auditory modalities and suggested that cognitive control is modality-specific, challenging the supramodal view. These discrepancies may have also arisen from methodological differences across studies. The current study examined the electroencephalographic profiles of a Stroop-like task to elucidate the modality-specific neural mechanisms of cognitive control. Participants were instructed to respond to a target always coming from the visual modality while disregarding the distractor coming from either the auditory or the visual modality. The results revealed significant congruency effects on both behavioral indices, i.e., reaction time and error rate, and ERP components, including the P3 and the conflict slow potential. Besides, the congruency effects on the amplitude of the P3 showed a negative correlation with reaction time, indicating an intrinsic link between these neural and behavioral indices. Furthermore, in the modality-repetition condition, conflict adaptation effects were significant on both reaction time and P3 amplitude, and the reaction time could be predicted by the P3 amplitude, while such effects were not observed in the modality-alternation condition. The time-frequency analysis also showed that conflict adaptation occurred in the modality-repetition condition, but not in the modality-alternation condition in low frequency bands, including the theta (4-8 Hz), alpha (8-12 Hz), and beta1 (12-20 Hz) bands. Taken together, our results revealed modality-specific patterns of the conflict adaptation effects on the P3 amplitude and oscillatory power (in theta, alpha, and beta1 bands), providing neural evidence for the modality specificity of cognitive control and expanding the boundaries of cognitive control.

DBU-Promoted Demethoxylative Thioannulation of Alkynyl Oxime Ethers with Sulfur for the Synthesis of Bisisothiazole-4-yl Disulfides.

An efficient synthesis of bisisothiazole-4-yl disulfides via the demethoxylative thioannulation of alkynyl oxime ethers with odorless elemental sulfur has been first developed. This transformation involves the N-O bond cleavage, the formation of multiple C-S and N-S bonds, providing an efficient way for constructions of both isothiazoles and disulfides. Straightforward elaboration of the products to isothiazole thioethers expands the synthetic utility of this reaction.

Seasonal variation of atmospheric vertical extinction and its interaction with meteorological factors in the Yangtze River Delta region.

Based on ground-based lidar and microwave radiometer observations in Hangzhou from 1 January 2013 to 31 December 2015, the monthly characteristics of diurnal extinction as well as atmospheric boundary layer (ABL) were studied. The interactions between temperature (T), humidity fields including relative humidity (RH) and specific humidity (SH) and atmospheric stratification (AS) were analyzed to discuss the meteorological factors in the Yangtze River Delta region during the study period. The top of ABLMPL varied from 0.8 km to 1.0 km throughout in January with higher extinction intensity close to the surface combined to the largest PM2.5 about 100-120 µg/m3. Then the ABLMPL could develop up to 1.5 km in the spring due to the weaker extinction during the daytime. The RH in the whole column in January and December was lower than the mean value (ranging from 5% to 20%) distributed from the ground to 3 km. From May to September, the RH anomaly profiles became positive contributed to larger extinction by strengthened the particle scattering ability. In January and December, the AS was stable from the surface to 3 km coincided with the extinction distribution; while in July and August, the gradient of Δθse decreased which favored the diffusion of particle in the air. Moreover, April and October presented turning points in the variation of θse. The humidity field reveals a stable condition in January and December which favored particles suppressed from the near surface to 3 km; the temperature field has tended towards a neutral state in most months except for February. The first change-point of the meteorological fields was found in April possibly attributable to the abnormal abrupt in the subtropical high. This study could have important reference for understanding regional air quality and governing air control.

Biomass burning and fungal spores as sources of fine aerosols in Yangtze River Delta, China - Using multiple organic tracers to understand variability, correlations and origins.

Research is restricted regarding impacts of biomass burning (BB) on fine aerosol (PM2.5), due mainly to lack of specific BB tracers. This study aims to characterize the variability, distributions, and contributions of BB and fungal spores as sources of PM2.5 using a multiple organic tracer approach. PM2.5 samples were collected at four representative sites in Yangtze River Delta (YRD), China every 6 days for one year. In the laboratory, samples were analyzed for three anhydrides (levoglucosan, mannosan, and galactosan), two sugar alcohols (arabitol and mannitol), water-soluble inorganic ions, and elemental/organic carbon (EC/OC). Levoglucosan was the most abundant BB tracer (mean concentration = 81 ng/m3), and fungal spore tracers arabitol and mannitol had similar abundances (5.6 and 5.7 ng/m3, respectively). Anhydrides and sugar alcohols had high within-group correlations, indicating their respective common sources. Concentrations of tracers displayed large temporal variations but small spatial variations, suggesting strong seasonality in BB and fungal spore sources. BB sources were burning of grass, pine needles, hardwood and crop straw, which were originated from transboundary/cross-region transport and local fire spots. PCA analyses revealed that the common sources of fine aerosols in YRD were secondary inorganic aerosols, soil dust, BB and fungal spores.

Copper-Catalyzed Tandem Sulfuration/Annulation of Propargylamines with Sulfur via C-N Bond Cleavage.

Copper-catalyzed aerobic oxidative sulfuration and annulation of propargylamines with elemental sulfur is described. The tandem reaction involves C-N bond cleavage and the formation of multiple C-S bonds, affording 1,2-dithiole-3-thiones in good to excellent yields with good functional group tolerance.

[Effects of Emission Reductions of Key Sources on the PM2.5 Concentrations in the Yangtze River Delta].

The effects of emission reductions of key sources (eight key industries and transportation) on the PM2.5 concentrations in the Yangtze River Delta (YRD) were investigated using the weather research forecast-chemistry (WRF-Chem) model in 2013 combined with two normal and enhanced emission reduction scenarios. The SO2, NOx, PM2.5, and NMVOC emissions in the YRD decrease by 36.3%, 26.3%, 32.0%, and 14.6% and by 51.4%, 39.6%, 37.6%, and 28.4% under the normal and enhanced emission reduction scenarios, respectively. The simulation results show that the annual mean PM2.5 concentrations over the national environmental monitoring sites in the YRD decline by 1.4-26.7 µg·m-3 and 2.1-32.3 µg·m-3, reflecting a decrease of 2.7%-23.1% and 3.9%-27.5%, under the two emission reduction scenarios, respectively. The nitrate in secondary inorganic aerosols contributes the most to the reduction of the annual mean PM2.5 concentration. The seasonal variation characteristics of the PM2.5 and secondary inorganic aerosol concentrations reflect that the smallest and largest declining rates occur in winter and summer, respectively. With increasing emission reduction, the declining rates of PM2.5 and the secondary inorganic aerosol concentrations in summer increase more compared with those in other seasons, resulting in a greater seasonal variation of the rates. The PM2.5 concentrations decrease by~20% in Shanghai and the Jiangsu Province under the enhanced emission scenario in summer. The analysis of the atmospheric oxidation shows that the atmospheric oxidation capacity is enhanced to different degrees by emission reductions of key sources in all seasons; it is further enhanced with increasing emission reduction. The enhanced oxidation capacity favors the formation of secondary PM2.5, thereby hindering the reduction of the PM2.5 concentration. The strongest hindrance occurs in winter, resulting in the worst PM2.5 pollution improvement. The atmospheric oxidation capacity is less affected by emission reductions of key sources in summer, making PM2.5 pollution improvement most effective. Furthermore, the negative effects of the enhancement of the atmospheric oxidation capacity on the reduction of the PM2.5 concentration in spring and autumn cannot be ignored.

[Characteristics and Source Analysis of Atmospheric Carbonaceous Aerosols in the Cities of Hangzhou and Ningbo].

To investigate the seasonal variations and sources of carbonaceous aerosols in the cities of Hangzhou and Ningbo, field PM2.5 sampling was conducted at four representative sites (two urban, one suburban, and one rural) in this region from December 2014 to November 2015. A thermal/optical carbon analyzer was employed to analyze both organic carbon (OC) and elemental carbon (EC) contents in PM2.5 by identifying eight different carbon fractions, including OC1, OC2, OC3, OC4+OPC, EC1-OPC, EC2, and EC3. Based on these fractions, OC and EC were defined as OC1+OC2+OC3+OC4+OPC and EC1+EC2+EC3-OPC, respectively; total carbon (TC) was calculated as the sum of OC and EC; and total carbonaceous aerosols (TCAs) were quantified via the sum of organic aerosols (OAs; converted from OC) and EC. The results showed the following. ①The annual average level of TC in this region was (14.3±4.1) µg·m-3, accounting for (26.2±6.5)% of the annual average PM2.5 concentration. The annual average OC and EC concentrations were (11.3±3.4) µg·m-3 and (3.0±0.9) µg·m-3, respectively. The highest TC level was observed in winter among the four seasons. ②The annual average TCA concentration in this region was (25.6±7.5) µg·m-3, contributing (42.2±10.0)% of PM2.5. In addition, secondary organic carbon (SOC) was also estimated by the commonly applied EC method. It was found that SOC contributed (41.1±5.5)% to OC on an annual average basis. ③The sources of carbonaceous aerosols were determined using the correlation between OC and EC, OC/EC mass ratio, and different carbon fraction characteristics. The annual average OC/EC ratio in this region was 4.7±1.7, which falls in the diagnostic ratio range for vehicular emissions, coal combustion, and biomass burning, indicating these sources are probably the major contributors of the regional carbonaceous aerosols. Moreover, a higher char-EC/soot-EC ratio was observed during winter and autumn at all sites, possibly implying the enhanced biomass burning activities during these two seasons.