Ozone response to precursors changes in the Chengdu-Chongqing economic circle, China, from satellite and ground-based observations.

Ozone (O3) pollution has become a noticeable problem in the Chengdu-Chongqing Economic Circle in China. The April-September MDA8 O3 level increases significantly by 2.26 µg m-3 year-1 from 2015 to 2023, with meteorological factors occupying merely 18 % in line with multivariate linear regression. To reveal the impact of anthropogenic emissions on O3 increase, O3 production sensitivity is accurately diagnosed by deriving localized thresholds for satellite formaldehyde (HCHO) to NO2 ratio and validated by in-situ measurements and observation-based model. Tracking volatile organic compounds (VOCs) and NOx through satellite HCHO and NO2, the O3 responses to precursor changes are assessed for long-term and special cases, and appropriate precursor reduction ratios are inferred. The results present that the transition range of satellite HCHO/NO2 from VOC-limited to NOx-limited in the region ranges from 2.7 to 4.3. The VOC-limited regime is concentrated in the urban areas of Chongqing and Chengdu as well as the central of the neighboring cities such as Deyang, Mianyang, and Meishan. The relative incremental reactivity from in-situ observations and box model at three sites in August 2019 demonstrates that O3 is most sensitive to anthropogenic VOC at urban and suburban sites, consistent with satellite results. Satellite and surface NO2 decrease at an annual rate of -2.1 % and - 2.9 % between 2015 and 2023, with larger decreases in Chengdu and Chongqing. In contrast, the trend of satellite HCHO is insignificant, indicating effective reduction in NOx but no significant reduction in VOC. This inappropriate reduction results in an increase in urban O3. The three short-term cases further validate the need for synergistic NOx and VOC reductions. Based on the relationship between O3 and satellite NO2 and HCHO, the minimum and optimal reduction ratios of VOC to NOx are 0.4:1 and 2.4:1 for the entire region, with higher ratios in Chengdu and Chongqing.

Substantial contribution of transported emissions to organic aerosol in Beijing.

Haze in Beijing is linked to atmospherically formed secondary organic aerosol, which has been shown to be particularly harmful to human health. However, the sources and formation pathways of these secondary aerosols remain largely unknown, hindering effective pollution mitigation. Here we have quantified the sources of organic aerosol via direct near-molecular observations in central Beijing. In winter, organic aerosol pollution arises mainly from fresh solid-fuel emissions and secondary organic aerosols originating from both solid-fuel combustion and aqueous processes, probably involving multiphase chemistry with aromatic compounds. The most severe haze is linked to secondary organic aerosols originating from solid-fuel combustion, transported from the Beijing-Tianjing-Hebei Plain and rural mountainous areas west of Beijing. In summer, the increased fraction of secondary organic aerosol is dominated by aromatic emissions from the Xi'an-Shanghai-Beijing region, while the contribution of biogenic emissions remains relatively small. Overall, we identify the main sources of secondary organic aerosol affecting Beijing, which clearly extend beyond the local emissions in Beijing. Our results suggest that targeting key organic precursor emission sectors regionally may be needed to effectively mitigate organic aerosol pollution.

Determinants of sedentary behavior in community-dwelling older adults with type 2 diabetes based on the behavioral change wheel: a path analysis.

BACKGROUND: Sedentary behavior (SB) is deeply ingrained in the daily lives of community-dwelling older adults with type 2 diabetes mellitus (T2DM). However, the specific underlying mechanisms of the determinants associated with SB remain elusive. We aimed to explore the determinants of SB based on the behavior change wheel framework as well as a literature review. METHODS: This cross-sectional study recruited 489 community-dwelling older adults with T2DM in Jinan City, Shandong Province, China. Convenience sampling was used to select participants from relevant communities. This study used the Measure of Older Adults' Sedentary Time-T2DM, the Abbreviated-Neighborhood Environment Walkability Scale, the Social Support Rating Scale, the Lubben Social Network Scale 6, the Subjective Social Norms Questionnaire for Sedentary Behavior, the Functional Activities Questionnaire, the Numerical Rating Scale, the Short Physical Performance Battery, and the Montreal Cognitive Assessment Text to assess the levels of and the determinants of SB. Descriptive statistical analysis and path analysis were conducted to analyze and interpret the data. RESULTS: Pain, cognitive function, social isolation, and social support had direct and indirect effects on SB in community-dwelling older adults with T2DM (total effects: ß = 0.426, ß = -0.171, ß = -0.209, and ß = -0.128, respectively), and physical function, walking environment, and social function had direct effects on patients' SB (total effects: ß = -0.180, ß = -0.163, and ß = 0.127, respectively). All the above pathways were statistically significant (P < 0.05). The path analysis showed that the model had acceptable fit indices: RMSEA = 0.014, χ 2/df = 1.100, GFI = 0.999, AGFI = 0.980, NFI = 0.997, RFI = 0.954, IFI = 1.000, TLI = 0.996, CFI = 1.000. CONCLUSION: Capability (physical function, pain, and cognitive function), opportunity (social isolation, walking environment, and social support), and motivation (social function) were effective predictors of SB in community-dwelling older adults with T2DM. Deeper knowledge regarding these associations may help healthcare providers design targeted intervention strategies to decrease levels of SB in this specific population.

Local incomplete combustion emissions define the PM2.5 oxidative potential in Northern India.

The oxidative potential (OP) of particulate matter (PM) is a major driver of PM-associated health effects. In India, the emission sources defining PM-OP, and their local/regional nature, are yet to be established. Here, to address this gap we determine the geographical origin, sources of PM, and its OP at five Indo-Gangetic Plain sites inside and outside Delhi. Our findings reveal that although uniformly high PM concentrations are recorded across the entire region, local emission sources and formation processes dominate PM pollution. Specifically, ammonium chloride, and organic aerosols (OA) from traffic exhaust, residential heating, and oxidation of unsaturated vapors from fossil fuels are the dominant PM sources inside Delhi. Ammonium sulfate and nitrate, and secondary OA from biomass burning vapors, are produced outside Delhi. Nevertheless, PM-OP is overwhelmingly driven by OA from incomplete combustion of biomass and fossil fuels, including traffic. These findings suggest that addressing local inefficient combustion processes can effectively mitigate PM health exposure in northern India.

"All about the value?" Decisional needs of breast reconstruction for breast cancer patients in the Chinese context: A mixed-methods study.

OBJECTIVE: To explore breast cancer (BC) patients' participation in breast reconstruction (BR) decision-making and specific decisional needs, especially the manifestations and causes of decisional conflicts, in China. METHODS: A mixed-methods study was conducted using triangulation of data from interviews and a questionnaire survey with health care professionals (HCPs) and BC patients with BR decision-making experience at 5 Beijing centers. The Ottawa Decision Support Framework guided (ODSF) the qualitative and quantitative data analyses. RESULTS: A total of 82.53% of Chinese BC patients would consider BR. Seven themes captured patients' BR decisional needs per the ODSF: inadequate support/resources (100%, 58.82%) and knowledge (75%, 52.94%) were most frequently cited. Health beliefs (unclear values) reflected Chinese characteristics. Patients had inadequate knowledge (M=19.99/50, SD=8.67) but positive BR attitudes (M=59.48/95, SD=10.45). CONCLUSIONS: BR decisions for Chinese BC patients are complex and often accompanied by decisional conflicts. Inadequate knowledge and inadequate support and resources contribute to these conflicts, emphasizing the need for culturally tailored information and support to promote SDM. PRACTICE IMPLICATIONS: HCPs need specialized training in SDM to guide patients in decision-making. It is essential to provide relevant resources and support that are culturally and clinically appropriate for Chinese patients.

Shared decision-making in healthcare in mainland China: a scoping review.

Background: Shared decision-making (SDM) facilitates the participation of healthcare professionals and patients in treatment decisions. We conducted a scoping review to assess SDM's current status in mainland China, referencing the Ottawa Decision Support Framework (ODSF). Methods: Our review encompassed extensive searches across six English and four Chinese databases, and various gray literature until April 30, 2021. Results were synthesized using thematic analysis. Results: Out of the 60 included studies, we identified three key themes based on the ODSF framework: decisional needs, decision support, and decisional outcomes. However, there appears to be a lack of comprehensive understanding of concepts related to decisional needs in China. Only a few studies have delved into feasibility, preference, choice, and outcome factors in the SDM process. Another challenge emerges from an absence of uniform standards for developing patient decision aids (PDAs). Furthermore, regarding health outcome indicators, their predominant focus remains on physiological needs. Conclusion: SDM is in its infancy in mainland China. It is important to explore the concept and expression of decisional needs in the context of Chinese culture. Subsequent studies should focus on constructing a scientifically rigorous and systematic approach for the development of PDAs, and considering the adaptation of SDM steps to the clinical context in China during SDM implementation. Concurrently, The focus on health outcomes in Chinese SDM studies, driven by the unique healthcare resource landscape, underscores the necessity of prioritizing basic needs within limited resources. Systematic review registration: https://inplasy.com/?s=202130021.

Characterizing the sources of ambient PM10 organic aerosol in urban and rural Catalonia, Spain.

Organic aerosols (OA) have recently been shown to be the dominant contributor to the oxidative potential of airborne particulate matter in northeastern Spain. We collected PM10 filter samples every fourth day from January 2017 to March 2018 at two sampling stations located in Barcelona city and Montseny Natural Park, representing urban and rural areas, respectively. The chemical composition of PM10 was analyzed offline using a broad set of analytical instruments, including high-resolution time-of-flight mass spectrometry (HR-ToF-AMS), a total organic carbon analyzer (TCA), inductively coupled plasma atomic emission spectrometry (ICP-AES), inductively coupled plasma mass spectrometry (ICP-MS), ion chromatography (IC), and thermal-optical carbon analyzer. Source apportionment analysis of the water-soluble organic content of the samples measured via HR-ToF-AMS revealed two primary and two secondary sources of OA, which included biomass-burning OA (BBOA), sulfur-containing OA (SCOA), as well as summer- and winter­oxygenated OA (SOOA and WOOA). The presence of hydrocarbon-like water-insoluble OA was also identified based on concentration trends in black carbon and nitrogen oxides. The results from the source apportionment analysis of the inorganic composition were correlated with different OA factors to assess potential source contributors. Barcelona showed significantly higher average water-soluble OA concentrations (5.63 ± 0.56 µg m-3) than Montseny (3.27 ± 0.37 µg m-3) over the sampling period. WOOA accounted for nearly 27 % of the averaged OA in Barcelona compared to only 7 % in Montseny. In contrast, SOOA had a greater contribution to OA in Montseny (47 %) than in Barcelona (24 %). SCOA and BBOA were responsible for 15-28 % of the OA at both sites. There were also seasonal variations in the relative contributions of different OA sources. Our overall results showed that local anthropogenic sources were primarily responsible for up to 70 % of ambient soluble OA in Barcelona, and regulating local-scale emissions could significantly improve air quality in urban Spain.

Cultural adaptation of the Pan-Canadian Oncology Symptom triage and remote support practice guide for cancer-related fatigue in China: Integration of traditional Chinese medicine nursing evidence.

Objective: This study aimed at culturally adapting pan-Canadian Oncology Symptom Triage and Remote Support (COSTaRS) Cancer-related fatigue (CRF) Practice Guide to enable its use in China. This article focuses on presenting the key cultural adaptation step: supplementing traditional Chinese medicine (TCM) nursing recommendations for CRF symptom management according to evidence. Methods: Guided by A Guideline Adaptation and Implementation Planning Resource (CAN-IMPLEMENT), the process for cultural adaptation of the CRF guide in the COSTaRS project included translation, expert committee review, acceptability and feasibility assessment, and targeted adaptation to include TCM nursing techniques for CRF management via the Delphi method. Results: First, an expert committee of nurses, nurse leaders, and researchers was established. The practice guide was translated and verified by the members of the expert committee. Nurses then rated the practice guide for acceptability and feasibility. Concurrently, 83 stakeholders (nurses and patients) identified five relevant TCM nursing techniques: acupuncture, moxibustion, acupressure therapy, Taijiquan, and auricular acupoint embedding. A systematic review of literature identified three clinical practice guidelines and four systematic reviews. Through two rounds of Delphi expert consultation, five TCM care strategies were added into the culturally adapted COSTaRS practice guide. Conclusions: Cultural adaptation of the Canadian CRF practice guide involved not only language translation but also the addition of relevant TCM evidence. Combining TCM evidence and the Delphi method was a novel aspect of the cultural adaptation process. Further research is needed to investigate the implementation of the guide in appropriate settings in China.

Digital Behavior Change Interventions to Reduce Sedentary Behavior and Promote Physical Activity in Adults with Diabetes: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

BACKGROUND: Technological advancements and ease of Internet access have increased the number of digital behavior change interventions (DBCIs). This systematic review and meta-analysis aimed to assess the effectiveness of DBCIs in reducing sedentary behavior (SB) and promoting physical activity (PA) in adults with diabetes. METHODS: A comprehensive search of seven databases-PubMed, Embase, PsycINFO, Cochrane Library, CINAHL, Web of Science, and Sedentary Behavior Research Database-was performed. Two reviewers independently carried out the study selection, data extraction, risk of bias assessment, and quality of evidence evaluation. Meta-analyses were performed where feasible; otherwise, narrative summaries were performed. RESULTS: A total of 13 randomized controlled trials with 980 participants met the inclusion criteria. Overall, DBCIs could significantly increase steps and the number of breaks in sedentary time. The subgroup analyses exhibited significant effects in DBCIs with over 10 behavior change techniques (BCTs) in improving steps, the time spent in light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA). The subgroup analyses showed a significant step increment in DBCIs of moderate and long durations, with over 4 BCT clusters, or in conjunction with a face-to-face component. The subgroup analyses also indicated significant effects in studies with ≥ 2 DBCI components in improving steps, the time spent in LPA and MVPA, and reducing sedentary time. CONCLUSION: There is some evidence that DBCI may increase PA and reduce SB in adults with type 2 diabetes. However, more high-quality studies are required. Future studies are needed to examine the potential of DBCIs in adults with type 1 diabetes.

VOC species controlling O3 formation in ambient air and their sources in Kaifeng, China.

The concentration of ozone has been in a rising crescendo in the last decade while the fine particles (PM2.5) is gradually decreasing but still at a high level in central China. Volatile organic compounds (VOCs) are the vital precursors of ozone and PM2.5. A total of 101 VOC species were measured in four seasons at five sites from 2019 to 2021 in Kaifeng. VOC sources and geographic origin of sources were identified by the positive matrix factorization (PMF) model and the hybrid single-particle Lagrangian integrated trajectory transport model. The source-specific OH loss rates (LOH) and ozone formation potential (OFP) were calculated to estimate the effects of each VOC source. The average mixing ratios of total VOCs (TVOC) were 43.15 parts per billion (ppb), of which the alkanes, alkenes, aromatics, halocarbons, and oxygenated VOCs respectively accounted for 49%, 12%, 11%, 14%, and 14%. Although the mixing ratios of alkenes were comparatively low, they played a dominant role in the LOH and OFP, especially ethene (0.55 s-1, 7%; 27.11 µg/m3, 10%) and 1,3-butadiene (0.74 s-1, 10%; 12.52 µg/m3, 5%). The vehicle-related source which emitted considerable alkenes ranked as the foremost contributing factor (21%). Biomass burning was probably influenced by other cities in the western and southern Henan and other provinces, Shandong and Hebei.

Spatial and species-specific responses of biogenic volatile organic compound (BVOC) emissions to elevated ozone from 2014-2020 in China.

China suffered from serious and elevated ozone (O3) pollution during 2014-2020. O3 exposure increased with W126, a biologically based cumulative exposure index, at a rate of 1.738 ppm-hr yr-1. MEGAN3.1 was applied to estimate biogenic volatile organic compound (BVOC) emissions and their response to O3 pollution in China by quantifying species responses to O3 stress. In 2020, China's BVOC emissions were 23.26 Tg when considering the effects of O3 pollution, which was 1.7 % higher than that without O3 stress. Isoprene, monoterpenes, sesquiterpenes, and other VOC emissions changed by -1.0 %, 1.4 %, 15.5 %, and 2.7 %, respectively. The stimulated BVOC emissions were mainly focused on the North China Plain (NCP) and a partial area of the Tibetan Plateau, which increased by >45 %. Changes in monthly emissions differed, with the greatest increase, 181 tons (3.25 %), in August. The seasonal patterns for the impacts of O3 pollution were also distinguished spatially. The elevated O3 exposure caused BVOC emission increases of 104.7 Gg yr-1 during 2014-2020, with isoprene, monoterpenes, sesquiterpenes, and other VOCs contributing -18.6 %, 27.5 %, 40.4 %, and 50.8 %, respectively. The greatest increase in emissions appeared on the NCP and eastern and central China, with annual increases of >100 tons per grid (36 km × 36 km). The interannual variations in BVOC emissions also displayed different seasonal patterns.

Implementation strategies to improve evidence-based practice for post-stroke dysphagia identification and management: A before-and-after study.

Objectives: Even though guidelines are available to guide dysphagia identification and management practice, there is still a gap between evidence and practice, which requires improvement. The purpose of this study was to determine the effect of using tailored, multifaceted strategies to improve evidence-based post-stroke dysphagia identification and management practice in a community hospital. Methods: Guided by the Knowledge to Action framework, the tailored, multifaceted strategies were developed and implemented for 5 months in a community hospital using a before-and-after study design. These strategies consisted of training intervention, policy intervention, and audit and feedback intervention. Nurses' level of knowledge and adherence, were collected in March 2019 and again in January 2020. Patients' quality of life and satisfaction were evaluated during the pre-intervention period (between February 2019 and April 2019) and the post-intervention period (between November 2019 and January 2020). Results: A total of 55 patients with post-stroke dysphagia (28 in the pre-intervention period and 27 in the post-intervention period) and 17 registered nurses were recruited. Following implementation, there were statistically significant improvements in patients' outcomes (quality of life and satisfaction) and nurses' outcomes (level of knowledge and adherence). Conclusions: This study assists in closing the research-practice gap by using tailored, multifaceted strategies to increase the use of evidence-based nursing care for dysphagia identification and management practices.

Unfolding and characterizing the barriers and facilitators of scaling-up evidence-based interventions from the stakeholders' perspective: a concept mapping approach.

INTRODUCTION AND AIMS: Much attention has been paid to scaling-up evidence-based interventions (EBIs) in previous implementation science studies. However, there is limited research on how stakeholders perceive factors of the scaling-up of EBIs. This study aimed to identify the barriers and facilitators of scaling-up the nurse-led evidence-based practice of post-stroke dysphagia identification and management (EBP-PSDIM) from the stakeholders' perspective, and to assess their importance and feasibility. METHODS: This study was conducted using concept mapping. Through purposive sampling, 18 stakeholders were recruited for brainstorming in which they responded to the focus prompt. Here, statements regarding perceived barriers and facilitators to EBI scaling-up were elicited and then sorted by similarity before being rated based on the importance and feasibility. Cluster analysis, multidimensional scaling, and descriptive statistics were utilized to analyze the data. RESULTS: Ultimately, 61 statements perceived to influence the scaling-up were grouped into four primary clusters, that is, community-related factors, resource team-related factors, evidence-based practice program-related factors, and scaling-up strategy-related factors. The 'perceived needs of the community' was rated as the most important and feasible factor to address, whereas 'costs/resource mobilization' was rated as the least important and feasible one. CONCLUSION: From the stakeholders' perspective, factors involved in the EBP-PSDIM program scaling-up were initially validated as being multidimensional and conceptually distinct;The importance and feasibility ratings of the barriers and facilitators could be used to help decision-makers to prioritize the most appropriate factors to be considered when developing implementation strategies.

Shared Decision-Making in Breast Reconstruction for Breast Cancer Patients: A Scoping Review.

For most breast cancer (BC) patients who have undergone a mastectomy, the decision whether to proceed with breast reconstruction (BR) is complicated and requires deliberation. Shared decision-making (SDM) helps to address those needs and promote informed value-based decisions. However, little is known about the SDM status for BR in BC patients. This scoping review describes: 1) basic characteristics of studies on BR SDM in BC patients; 2) factors influencing BR SDM in BC patients; 3) experience and perception of BR SDM in BC patients; and 4) outcome measures reported. This review was performed in accordance with the Arksey and O'Malley methodology. A total of 5 English and 4 Chinese databases were searched, as well as different sources from grey literature. The data extraction form was developed by referring to the objectives and the Ottawa Decision Support Framework (ODSF). Data was analyzed using thematic analysis, framework analysis and descriptive statistics, with findings presented in the tables and diagrams. A total of 1481 records were retrieved and 42 of these included after screening. In 21 (21/42, 50%) of the studies, patient decision aids (PDAs) were utilized, and in 17 (17/42, 40.48%) of the studies, the factors influencing the implementation of SDM were explored. Of these 17 studies, the factors influencing the implementation of SDM were categorized into the following: the patient level (17/17, 100%), the healthcare level (2/17, 11.76%) and the organizational and system level (7/17, 41.18%). A total of 8 (19.05%) of the 42 studies focused on patients' experiences and perceptions of SDM, and all studies used qualitative research methods. Of these 8 studies, a total of 7 (7/8, 87.50%) focused on patients' experiences of SDM participation, and 4 (4/8, 50.00%) focused on patients' perceptions of SDM. A total of 24 studies (24/42, 57.14%) involved quantitative outcome measures, where 49 items were divided into three classifications according to the outcomes of ODSF: the quality of the decision (17/24, 70.83%), the quality of the decision-making process (20/24, 83.33%), and impact (13/24, 54.17%). Although researchers have paid less attention to other research points in the field of SDM, compared to the design and application of SDM interventional tools, the research team still presents some equally noteworthy points through scoping review. For instance, the various factors influencing BC patients' participation in SDM for BR (especially at the healthcare provider level and at the organizational system level), patients' experiences and perceptions. Systematic reviews (SRs) should be conducted to quantify the impact of these different factors on BR SDM. Implementation of scientific theories and methods can inform the exploration and integration of these factors.

[Spatio-Temporal Variations and Source Apportionment of Carbonaceous Species in PM2.5 Across Multiple Sampling Locations in the Chengdu Plain].

To understand the characteristics and sources of carbonaceous aerosols, one-year PM2.5 samples were analyzed for their organic carbon (OC) and elemental carbon (EC) content, following the thermal/optical transmission protocol in three cities[Deyang (DY), Chengdu (CD), and Meishan (MS)] in the Chengdu Plain. The observed annual average concentrations (µg·m-3) were in the following order:MS (15.8±9.6 OC and 6.6±5.3 EC) > CD (13.0±7.5 OC and 4.7±3.6 EC) > DY (9.6±6.1 OC and 3.4±2.6 EC). Organic matter (1.6OC) and EC was regarded as the total carbonaceous aerosols (TCA) amount, and the TCA/PM2.5 ratios at the three above-mentioned cities were 36%, 34%, and 30% respectively. The EC-trace method was used to estimate secondary organic carbon (SOC), which accounted for 38%, 46%, and 47% of total OC in MS, CD, and DY. Daily variations of OC and EC concentrations exhibited significant daily variations, with simultaneous peaks on Oct. 12th to 13th, 2013, Dec. 2nd to 7th, 2013, and mid-to-late Jan., 2014. The surging concentrations of K+ during the pollution period implied the contribution of biomass burning to heavy pollution. Six sources were resolved by the positive matrix factorization (PMF) model, whose contributions to the total carbon (TC) were:biomass burning (46%-56%), secondary aerosols (26%-38%), vehicle emission (9%-12%), fugitive dust (3%-4%), coal combustion (2%-3%), and industry emission (1%-2%). Biomass burning activities presented a significant influence on TC throughout the year, especially in autumn and winter.

Spatiotemporal patterns of PM2.5 elemental composition over China and associated health risks.

Trace metals in atmospheric particulate matter (PM) are a serious threat to public health. Although pollution from toxic metals has been investigated in many Chinese cities, the spatial and temporal patterns in PM2.5 remain largely unknown. Long-term PM2.5 field sampling in 11 cities, combined with a systemic literature survey covering 51 cities, provides the first comprehensive database of 21 PM2.5-bound trace metals in China. Our results revealed that PM2.5 elemental compositions varied greatly, with generally higher levels in North China, especially for crustal elements. Pollution with Cr, As, and Cd was most serious, with 61, 38, and 16 sites, respectively, surpassing national standards, including some in rural areas. Local emissions, particularly from metallurgical industries, were the dominant factors driving the distribution in polluted cities such as Hengyang, Yuncheng, and Baiyin, which are mainly in North and Central China. Elevated As, Cd, and Cr levels in Yunnan, Guizhou Province within Southwest China were attributed to the high metal content of local coal. Diverse temporal trends of various elements that differed among regions indicated the complexity of emission patterns across the country. The results demonstrated high non-carcinogenic risks for those exposed to trace metals, especially for children and residents of heavily cities highly polluted with As, Pb, or Mn. The estimated carcinogenic risks ranged from 6.61 × 10-6 to 1.92 × 10-4 throughout China, with As being the highest priority element for control, followed by Cr and Cd. Regional diversity in major toxic metals was also revealed, highlighting the need for regional mitigation policies to protect vulnerable populations.

Investigating the impacts of coal-fired power plants on ambient PM2.5 by a combination of a chemical transport model and receptor model.

Aimed at evaluating the impacts of coal-fired power plants on urban air quality and human health, a one-month intensive observation campaign was conducted in a typical polluted city located in the 2 + 26 city cluster (Beijing, Tianjin and 26 other cities) of the North China Plain in December 2017. The observation results illustrated that the coal-fired power plant in this city increased the monthly average fine particulate matter (PM2.5) concentration by ~5% at the city scale. The impacts differed under various diffusion conditions. A three-dimensional nested air quality condition model (the Nested Air Quality Perdition Model System or NAQPMS) with source apportionment was employed to analyze the impacts. The results indicated that power plants had the largest effect on regional air quality during the severe-pollution period, while any influence could be ignored during periods with excellent dissipation under robust winds. PM2.5 contributed by the power plant mainly occurred below 150 m, diffused 100 km away, and reached a level of approximately 5 µg m-3 during the light-pollution period. During the accumulation period, the plume reached a height of 500 m, diffused to the downwind area approximately 100 km away within half a day, and contributed at most 40 µg m-3 to PM2.5. The affected area expanded to 250 km during the severe-pollution period, and the contribution to PM2.5 was at least 10 µg m-3 at different distances. The affected height reached approximately 500 m, with PM2.5 exceeding 10 µg m-3, mainly constrained below 150 m. Overall, regional integrated control strategies should be implemented for the power plants in the 2 + 26 city cluster during pollution episodes to further improve air quality.

Quantification of primary and secondary sources to PM2.5 using an improved source regional apportionment method in an industrial city, China.

Identifying and quantifying the major sources of atmospheric particulate matter (PM) is essential for the development of pollution mitigation strategies to protect public health. However, urban PM is affected by local primary emissions, transport, and secondary formation; therefore, advanced methods are needed to elucidate the complex sources and transport patterns. Here, an improved source apportionment method was developed by incorporating the receptor model, Lagrangian simulation, and emissions inventories to quantify PM2.5 sources for an industrial city in China. PM2.5 data including ions, metals, organic carbon, and elemental carbon were obtained by analyzing 1 year of sampling results at urban and rural sites. This method identified coal combustion (30.64%), fugitive dust (13.25%), and vehicles (12.51%) as major primary sources. Secondary sources, including sulfate, nitrate, and secondary organic aerosols also contributed strongly (25.28%-30.76% in total) over urban and rural areas. Hebei Province was the major regional source contributor (43.05%-57.51%) except for fugitive dust, on which Inner Mongolia had a greater impact (43.51%). The megacities of Beijing and Tianjin exerted strong regional impacts on the secondary nitrate and secondary organic aerosols factors, contributing 11.32% and 15.65%, respectively. Pollution events were driven largely by secondary inorganic aerosols, highlighting the importance of reducing precursor emissions at the regional scale, particularly in the Beijing-Tianjin-Hebei region. Overall, our results demonstrate that this novel method offers good flexibility and efficiency for quantifying PM2.5 sources and regional contributions, and that it can be extended to other cities.

Characteristics and sources of carbonaceous aerosol across urban and rural sites in a rapidly urbanized but low-level industrialized city in the Sichuan Basin, China.

Organic carbon (OC) and elemental carbon (EC) were measured in 24 h fine particulate matter (PM2.5) samples collected from May 2015 to April 2016 at urban and rural sites in Nanchong, a rapidly urbanized but low-level industrialized city in the Sichuan Basin, China. The annual average PM2.5, OC, and EC concentrations at urban sites were 45.6-55.7, 8.5-11.5, and 2.8-3.4 µg m-3, respectively, which were similar to the corresponding values (48.3, 10.6, and 3.3 µg m-3) at the rural site. The PM2.5 concentrations displayed strong monthly variations, with the highest (78.8-105.0 µg m-3) in January or February. Likewise, daily OC and EC concentrations exhibited high values in October (only for OC) and December 2015 to February 2016. Correlation, positive matrix factorization, and concentration weighted trajectory analyses were combined to investigate the sources of carbonaceous aerosol. The results indicated that OC and EC were mainly from biomass burning (60.7% and 45.8%) and coal combustion (30.2% and 25.7%), followed by vehicle emissions and road dust. The enhanced emissions from residential coal and biofuel uses in winter and straw combustion in October contributed to higher concentrations of OC and EC during these months. The contributions of biomass burning to OC and EC were significantly higher at the rural site (69.2% and 51.8%) than urban sites (56.3-58.6% and 37.8-41.5%). In addition to local emissions, the high concentrations of OC and EC at Nanchong were also influenced by regional transport in the basin.