Effect of Miscellaneous Meals Replacing Soybean Meal in Feed on Growth Performance, Serum Biochemical Parameters, and Microbiota Composition of 25-50 kg Growing Pigs.

The present study aims to determine the effect of miscellaneous meals (rapeseed meal, cottonseed meal, and sunflower meal) replacing soybean meal in feed on growth performance, apparent digestibility of nutrients, serum biochemical parameters, serum free amino acid content, microbiota composition and SCFAs content in growing pigs (25-50 kg). A total of 72 (Duroc × Landrace × Yorkshire) growing pigs with initial weights of 25.79 ± 0.23 kg were randomly divided into three treatments. The pigs were fed corn-soybean meal (CON), corn-soybean-miscellaneous meals (CSM), and corn-miscellaneous meals (CMM). Each treatment included six replicates with four pigs per pen (n = 24, 12 barrows and 12 gilts). Soybean meal accounted for 22.10% of the basal diet in the CON group. In the CSM group, miscellaneous meals partially replaced soybean meal with a mixture of 4.50% rapeseed meal, 3.98% cottonseed meal, and 4.50% sunflower meal. In the CMM group, miscellaneous meals entirely replaced soybean meal with a mixture of 8.50% rapeseed meal, 8.62% cottonseed meal, and 8.5% sunflower. The results showed that compared with the CON, the CSM and CMM groups significantly improved the average daily gain (ADG) of growing pigs during the 25-50 kg stage (p < 0.05) but had no effects on average daily feed intake (ADFI) and average daily feed intake/average daily gain (F/G) (p > 0.05). Moreover, the CMM group significantly reduced nutrient apparent digestibility of gross energy compared with the CON group. The serum biochemical parameters results showed that the CSM group significantly improved the contents of total protein (TP) compared with the CON group (p < 0.05). The CMM group significantly improved the contents of total protein (TP), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) compared with the CON group in serum (p < 0.05). In comparison with the CON group, the CMM group also significantly improved lysine (Lys), threonine (Thr), valine (Val), isoleucine (Ile), leucine (Leu), phenylalanine (Phe), arginine (Arg), and citrulline (Cit) levels in serum (p < 0.05). However, the CMM group significantly decreased non-essential amino acid content glycine (Gly) in serum compared with CON (p < 0.05), while compared with the CON group, the CSM and CMM groups had no significant effects on the relative abundance, the alpha-diversity, or the beta-diversity of fecal microbiota. Moreover, compared with the CON group, the CSM group significantly increased butyric acid and valeric acid contents of short-chain fatty acids (SCFAs) in feces (p < 0.05). In contrast to the CON group, the CMM group significantly reduced the contents of SCFAs in feces, including acetic acid, propionic acid, and isobutyric acid (p < 0.05). Collectively, the results of the present study indicate that miscellaneous meals (rapeseed meal, cottonseed meal, and sunflower meal) can partially replace the soybean meal and significantly improve the growth performance of growing pigs during the 25-50 kg stage. Thus, miscellaneous meals are a suitable protein source as basal diets to replace soybean meals for 25-50 kg growing pigs. These results can be helpful to further develop miscellaneous meals as a functional alternative feed ingredient to soybean meal.

Estimated health effects from domestic use of gaseous fuels for cooking and heating in high-income, middle-income, and low-income countries: a systematic review and meta-analyses.

BACKGROUND: Exposure to household air pollution from polluting domestic fuel (solid fuel and kerosene) represents a substantial global public health burden and there is an urgent need for rapid transition to clean domestic fuels. Gas for cooking and heating might possibly affect child asthma, wheezing, and respiratory health. The aim of this review was to synthesise the evidence on the health effects of gaseous fuels to inform policies for scalable clean household energy. METHODS: In this systematic review and meta-analysis, we summarised the health effects from cooking or heating with gas compared with polluting fuels (eg, wood or charcoal) and clean energy (eg, electricity and solar energy). We searched PubMed, Scopus, Web of Science, MEDLINE, Cochrane Library (CENTRAL), Environment Complete, GreenFile, Google Scholar, Wanfang DATA, and CNKI for articles published between Dec 16, 2020, and Feb 6, 2021. Studies eligible for inclusion had to compare gas for cooking or heating with polluting fuels (eg, wood or charcoal) or clean energy (eg, electricity or solar energy) and present data for health outcomes in general populations. Studies that reported health outcomes that were exacerbations of existing underlying conditions were excluded. Several of our reviewers were involved in screening studies, data extraction, and quality assessment (including risk of bias) of included studies; 20% of studies were independently screened, extracted and quality assessed by another reviewer. Disagreements were reconciled through discussion with the wider review team. Included studies were appraised for quality using the Liverpool Quality Assessment Tools. Key health outcomes were grouped for meta-analysis and analysed using Cochrane's RevMan software. Primary outcomes were health effects (eg, acute lower respiratory infections) and secondary outcomes were health symptoms (eg, respiratory symptoms such as wheeze, cough, or breathlessness). This study is registered with PROSPERO, CRD42021227092. FINDINGS: 116 studies were included in the meta-analysis (two [2%] randomised controlled trials, 13 [11%] case-control studies, 23 [20%] cohort studies, and 78 [67%] cross-sectional studies), contributing 215 effect estimates for five grouped health outcomes. Compared with polluting fuels, use of gas significantly lowered the risk of pneumonia (OR 0·54, 95% CI 0·38-0·77; p=0·00080), wheeze (OR 0·42, 0·30-0·59; p<0·0001), cough (OR 0·44, 0·32-0·62; p<0·0001), breathlessness (OR 0·40, 0·21-0·76; p=0·0052), chronic obstructive pulmonary disease (OR 0·37, 0·23-0·60; p<0·0001), bronchitis (OR 0·60, 0·43-0·82; p=0·0015), pulmonary function deficit (OR 0·27, 0·17-0·44; p<0·0001), severe respiratory illness or death (OR 0·27, 0·11-0·63; p=0·0024), preterm birth (OR 0·66, 0·45-0·97; p=0·033), and low birth weight (OR 0·70, 0·53-0·93; p=0·015). Non-statistically significant effects were observed for asthma in children (OR 1·04, 0·70-1·55; p=0·84), asthma in adults (OR 0·65, 0·43-1·00; p=0·052), and small for gestational age (OR 1·04, 0·89-1·21; p=0·62). Compared with electricity, use of gas significantly increased risk of pneumonia (OR 1·26, 1·03-1·53; p=0·025) and chronic obstructive pulmonary disease (OR 1·15, 1·06-1·25; p=0·0011), although smaller non-significant effects were observed for higher-quality studies. In addition, a small increased risk of asthma in children was not significant (OR 1·09, 0·99-1·19; p=0·071) and no significant associations were found for adult asthma, wheeze, cough, and breathlessness (p>0·05). A significant decreased risk of bronchitis was observed (OR 0·87, 0·81-0·93; p<0·0001). INTERPRETATION: Switching from polluting fuels to gaseous household fuels could lower health risk and associated morbidity and mortality in resource-poor countries where reliance on polluting fuels is greatest. Although gas fuel use was associated with a slightly higher risk for some health outcomes compared with electricity, gas is an important transitional option for health in countries where access to reliable electricity supply for cooking or heating is not feasible in the near term. FUNDING: WHO.

Effect of mixed meal replacement of soybean meal on growth performance, nutrient apparent digestibility, and gut microbiota of finishing pigs.

Introduction: This study was carried out to investigate the effects of mixed meal (rapeseed meal, cotton meal, and sunflower meal) replacement soybean meal on growth performance, nutrient apparent digestibility, serum inflammatory factors and immunoglobulins, serum biochemical parameters, intestinal permeability, short-chain fatty acid content, and gut microbiota of finishing pigs. Methods: A total of 54 pigs with an average initial weight of 97.60 ± 0.30 kg were selected and randomly divided into 3 groups according to their initial weight, with 6 replicates in each group and 3 pigs in each replicate. The trial period was 26 days. The groups were as follows: control group (CON), fed corn-soybean meal type basal diet; Corn-soybean-mixed meal group (CSM), fed corn-soybean meal-mixed meal diet with a ratio of rapeseed meal, cotton meal, and sunflower meal of 1:1:1 to replace 9.06% soybean meal in the basal diet; Corn-mixed meal group (CMM), fed a corn-mixed meal diet with a ratio of Rapeseed meal, Cotton meal and Sunflower meal of 1:1:1 to replace soybean meal in the basal diet completely. The crude protein level of the three diets was maintained at 12.5%. Results: Our findings revealed no significant impact of replacing soybean meal with the mixed meal (rapeseed meal, cotton meal, and sunflower meal) on the ADG (Average daily gain), ADFI (Average daily feed intake), and F/G (Feed gain ratio) (P > 0.05), or crude protein, crude fat, and gross energy (P > 0.05) in the diet of finishing pigs. Compared with the CON group, the serum interleukin 6 (IL-6) and interleukin 10 (IL-10) concentrations were significantly decreased in the CMM group (P < 0.05). However, there is no significant effect of the mixed meal (rapeseed meal, cotton meal, and sunflower meal) replacing soybean meal in the diet on the serum interleukin 1ß (IL-1ß), interleukin 8 (IL-8), tumor necrosis factor-alpha (TNF-α), immunoglobulin A (IgA), immunoglobulin G (IgG), and immunoglobulin M (IgM) concentrations (P > 0.05). Concordantly, there is no significant effect of mixed meal (rapeseed meal, cotton meal, and sunflower meal) replacing soybean meal in the diet on the serum antioxidant capacity, such as total antioxidant capacity (T-AOC), catalase (CAT), and malondialdehyde (MDA) levels of finishing pigs. Moreover, compared with the CON group, serum low-density lipoprotein (LDL-C) levels were significantly lower in the CSM group (P < 0.05) and their total bilirubin (TBIL) levels were significantly lower in the CMM group (P < 0.05). There is not a significant effect on serum D-lactate and diamine oxidase (DAO) concentrations (P > 0.05). The next section of the survey showed that the replacement of soybean meal with a mixed meal (rapeseed meal, cotton meal, and sunflower meal) in the diet did not significantly influence the acetic acid, propionic acid, butyric acid, valeric acid, isobutyric acid, and isovaleric acid in the colon contents (P > 0.05). Furthermore, compared with the CON group, the CMM group diet significantly increased the abundance of Actinobacteria at the phylum level (P < 0.05), U_Actinobacteria at the class level (P < 0.05), and U_Bacteria at the class level (P < 0.05). The result also showed that the CMM group significantly reduced the abundance of Oscillospirales at the order level (P < 0.05) and Streptococcaceae at the family level (P < 0.05) compared with the CON group. The Spearman correlation analysis depicted a statistically significant positive correlation identified at the class level between the relative abundance of U_Bacteria and the serum T. BILI concentrations (P < 0.05). Moreover, a significant negative correlation was detected at the order level between the relative abundance of Oscillospirales and the levels of acetic and propionic acids in the colonic contents (P < 0.05). Additionally, there was a significant positive correlation between the serum concentrations of IL-6 and IL-10 and the relative abundance of the family Streptococcaceae (P < 0.05). Discussion: This study demonstrated that the mixed meal (rapeseed meal, cotton meal, and sunflower meal) as a substitute for soybean meal in the diet had no significant negative effects on the growth performance, nutrient apparent digestibility, serum immunoglobulins, serum antioxidant capacity, intestinal permeability, short-chain fatty acid content, and diversity of gut microbiota of finishing pigs. These results can help develop further mixed meals (rapeseed meal, cotton meal, and sunflower meal) as a functional alternative feed ingredient for soybean meals in pig diets.

Household energy stacking and structures in Pakistan - Results from a multiple-energy study in Azad Kashmir and Punjab.

Solid fuel use (SFU) is common in most developing countries and would release many hazardous air pollutants posing high risks on human health. The Global Burden of Disease (GBD) study highlighted risks associated with household SFU in Pakistan, however, high uncertainties prevail because of scanty data on SFU and unaccounted energy stacking. This study conducted a field campaign aiming at collecting first-hand data on household energy mix in Pakistan. The first survey was in Punjab and Azad Kashmir, and revealed that stacked energy use was pervasive, especially for cooking. The stacking was found to be much more obvious in SFU households (defined as those using SFU dominantly) compared to those non-SFU. There were significantly substantial differences between Azad Kashmir and Punjab because of distinct resources available and economic conditions. Woody materials comprised up to nearly 70% in Azad Kashmir, but in Punjab, gas was frequently used for cooking. Only investigating primary household energy would probably overestimate main energy types that being used for a longer time but underestimated other supplements, suggesting the preference of multiple-energy surveys in household energy studies.

Interpreting Highly Variable Indoor PM2.5 in Rural North China Using Machine Learning.

Household air pollution associated with solid fuel use is a long-standing public concern. The global population mainly using solid fuels for cooking remains large. Besides cooking, large amounts of coal and biomass fuels are burned for space heating during cold seasons in many regions. In this study, a wintertime multiple-region field campaign was carried out in north China to evaluate indoor PM2.5 variations. With hourly resolved data from ∼1600 households, key influencing factors of indoor PM2.5 were identified from a machine learning approach, and a random forest regression (RFR) model was further developed to quantitatively assess the impacts of household energy transition on indoor PM2.5. The indoor PM2.5 concentration averaged at 120 µg/m3 but ranged from 16 to ∼400 µg/m3. Indoor PM2.5 was ∼60% lower in families using clean heating approaches compared to those burning traditional coal or biomass fuels. The RFR model had a good performance (R2 = 0.85), and the interpretation was consistent with the field observation. A transition to clean coals or biomass pellets can reduce indoor PM2.5 by 20%, and further switching to clean modern energies would reduce it an additional 30%, suggesting many significant benefits in promoting clean transitions in household heating activities.

Research Note: Dietary resveratrol supplementation improves the hepatic antioxidant capacity and attenuates lipopolysaccharide-induced inflammation in yellow-feathered broilers.

This experiment investigated the protective effect of resveratrol (RES) on the hepatic antioxidant status and systemic inflammation in yellow-feathered broilers challenged with lipopolysaccharide (LPS). A total of 240 healthy 1-day-old yellow-feathered broilers were randomly divided into 4 groups (control, LPS, RES, and RES+LPS), with 5 replicates of 12 chickens per replicate. The experiment lasted 21 d. The broilers were fed with either the basal diet or the basal diet supplemented with 400 mg/kg RES followed by intraperitoneal challenge with LPS (1 mg/kg body weight) or the same amount of saline at d 16, 18, and 20. The results showed that dietary RES supplementation could improve the activities of total antioxidant capacity (T-AOC) and superoxide dismutase (SOD) in the liver of yellow-feathered broilers challenged with LPS (P < 0.05). Furthermore, LPS challenge increased the plasma interleukin-17 (IL-17) concentration, the hepatic interleukin-6 (IL-6) and interleukin-1ß (IL-1ß) concentrations, as well as the concentrations of tumor necrosis factor (TNF-α), IL-6, and IL-1ß in the spleen (P < 0.05), and decreased the transforming growth factor-ß (TGF-ß) concentrations in the plasma, liver, and spleen (P < 0.05). However, dietary RES supplementation could reduce the increased TNF-α levels in the plasma, liver, and spleen induced by LPS, and increased TGF-ß level in the liver and spleen (P < 0.05). Collectively, these results suggest that dietary RES supplementation could effectively improve the hepatic antioxidant capacity and attenuate LPS-induced inflammation in yellow-feathered broilers during the starter stage.

Identification of Factors Determining Household PM2.5 Variations at Regional Scale and Their Implications for Pollution Mitigation.

Indoor PM2.5, particulate matter no more than 2.5 µm in aerodynamic equivalent diameter, has very high spatiotemporal variabilities; and exploring the key factors influencing the variabilities is critical for purifying air and protecting human health. Here, we conducted a longer-term field monitoring campaign using low-cost sensors and evaluated inter- and intra-household PM2.5 variations in rural areas where energy or stove stacking is common. Household PM2.5 varied largely across different homes but also within households. Using generalized linear models and dominance analysis, we estimated that outdoor PM2.5 explained 19% of the intrahousehold variation in indoor daily PM2.5, whereas factors like the outdoor temperature and indoor-outdoor temperature difference that was associated with energy use directly or indirectly, explained 26% of the temporal variation. Inter-household variation was lower than intrahousehold variation. The inter-household variation was strongly associated with distinct internal sources, with energy-use-associated factors explaining 35% of the variation. The statistical source apportionment model estimated that solid fuel burning for heating contributed an average of 31%-55% of PM2.5 annually, whereas the contribution of sources originating from the outdoors was ≤10%. By replacing raw biomass or coal with biomass pellets in gasifier burners for heating, indoor PM2.5 could be significantly reduced and indoor temperature substantially increased, providing thermal comforts in addition to improved air quality.

Variabilities in Primary N-Containing Aromatic Compound Emissions from Residential Solid Fuel Combustion and Implications for Source Tracers.

Nitroaromatic compounds (NACs) not only are strongly absorbing chromophores but also adversely affect human health. NACs can be emitted from incomplete combustions and can derive secondarily through photochemical reactions. Here, emission experiments were conducted for 31 fuel-stove combinations to elucidate variations in, and influencing factors of, NAC emission factors (EF∑NACs) and to explore potential tracers for different combustion sources. EF∑NACs varied by 2 orders of magnitude among different combinations. Differences in fuel type contributed more than the stove difference to the observed variation. EF∑NACs for biomass pellets was approximately 66% lower than that for raw biomass, although the bulk organic and brown carbon EFs were 95% lower. 2-Nitro-1-naphthol was the most abundant individual compound, followed by 4-nitrocatechol, while acid compounds (salicylic acid and benzoic acid) were low in abundance (<1%). Substantially different profiles were observed between coal and biomass burning emissions. Biomass burning had more single-ring-based phenolic compounds with more 4-nitrocatechol, while in coal combustion, more two-ring products were produced. This study demonstrated much lower ratios of 2-nitro-1-naphthol/4-nitrocatechol for biomass in both traditional (2.0 ± 3.5) and improved stoves (3.0 ± 2.1) than for coals (15 ± 6). Coal and biomass burning differed in not only EF∑NACs but also compound profile, consequently leading to distinct health and climate impacts; moreover, the ratio of 2-nitro-1-naphthol/4-nitrocatechol may be used in source apportionment of NACs.

Effect of dietary resveratrol supplementation on growth performance, antioxidant capacity, intestinal immunity and gut microbiota in yellow-feathered broilers challenged with lipopolysaccharide.

Resveratrol (RES) displays strong antioxidant and anti-inflammatory properties in protecting the animals from various stressors and inflammatory injuries, but its interrelationship with the gut microbiota remained largely unclear. This study was carried out to investigate the effects of dietary RES supplementation on growth performance, antioxidant capacity, intestinal immunity and gut microbiota in yellow-feathered broilers challenged by lipopolysaccharide (LPS). A total of 240 yellow-feathered broilers were randomly assigned to four treatment groups in a 2 × 2 factorial design. The broilers were fed with the control diet or control diet supplemented with 400 mg/kg RES, followed by challenge with LPS or the same amount of saline. Dietary RES supplementation significantly alleviated the decreases in the final body weight (BW), average daily gain (ADG), and ADFI induced by LPS (P < 0.05). LPS challenge significantly increased plasma concentrations of triglyceride, high-density lipoprotein cholesterol (HDL-C), aspartate aminotransferase (AST), and cortisol levels, but decreased triiodothyronine (T3) and insulin levels (P < 0.05). Dietary supplementation with RES significantly reversed the elevated creatinine concentrations and the decreased concentrations of T3 and insulin caused by LPS (P < 0.05). Moreover, dietary RES supplementation significantly increased plasma total antioxidant capacity (T-AOC) and catalase (CAT) activities and superoxide dismutase (SOD) and T-AOC activities in jejunal mucosa and reduced malondialdehyde (MDA) concentration in the plasma (P < 0.05). The reduction in the villus height to crypt depth ratio in duodenum, jejunum and ileum and the shortening of villus height in jejunum and ileum caused by LPS were also alleviated by RES treatment (P < 0.05). Furthermore, the increased concentrations of intestinal tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and IL-1ß caused by LPS were significantly decreased by RES treatment (P < 0.05). Dietary RES treatment increased the mRNA expression of claudin-1, claudin-5, occludin, and zonula occludens-1 (ZO-1), and decreased mRNA expression of IL-1ß, IL-8, IL-17, and TNF-α after LPS challenge (P < 0.05). Dietary RES treatments significantly decreased the dominance of cecal microbiota, and increased the Pieiou-e and Simpson index. Moreover, dietary RES supplementation increased relative abundance of UCG_ 009, Erysipelotrichaceae, Christensenellaceae_R-7_group, Anaerotruncus, RF39, and Ruminococcus while decreasing the abundance of Alistipes at genus level. Spearman correlation analysis revealed that the microbes at the order and genus levels significantly correlated with indicators of growth performance, antioxidant capacity, and intestinal health. Collectively, dietary supplementation with 400 mg/kg RES could improve growth performance and antioxidant capacity, and modulate intestinal immunity in yellow-feathered broilers challenged by LPS at early stage, which might be closely associated with the regulation of gut microbiota community composition.

Impacts of Household Coal Combustion on Indoor Ultrafine Particles-A Preliminary Case Study and Implication on Exposure Reduction.

Ultrafine particles (UFPs) significantly affect human health and climate. UFPs can be produced largely from the incomplete burning of solid fuels in stoves; however, indoor UFPs are less studied compared to outdoor UFPs, especially in coal-combustion homes. In this study, indoor and outdoor UFP concentrations were measured simultaneously by using a portable instrument, and internal and outdoor source contributions to indoor UFPs were estimated using a statistical approach based on highly temporally resolved data. The total concentrations of indoor UFPs in a rural household with the presence of coal burning were as high as 1.64 × 105 (1.32 × 105-2.09 × 105 as interquartile range) #/cm3, which was nearly one order of magnitude higher than that of outdoor UFPs. Indoor UFPs were unimodal, with the greatest abundance of particles in the size range of 31.6-100 nm. The indoor-to-outdoor ratio of UFPs in a rural household was about 6.4 (2.7-16.0), while it was 0.89 (0.88-0.91) in a home without strong internal sources. A dynamic process illustrated that the particle number concentration increased by ~5 times during the coal ignition period. Indoor coal combustion made up to over 80% of indoor UFPs, while in an urban home without coal combustion sources indoors, the outdoor sources may contribute to nearly 90% of indoor UFPs. A high number concentration and a greater number of finer particles in homes with the presence of coal combustion indicated serious health hazards associated with UFP exposure and the necessity for future controls on indoor UFPs.

CircOGDH Is a Penumbra Biomarker and Therapeutic Target in Acute Ischemic Stroke.

BACKGROUND: Acute ischemic stroke (AIS) is a leading cause of disability and mortality worldwide. Prediction of penumbra existence after AIS is crucial for making decision on reperfusion therapy. Yet a fast, inexpensive, simple, and noninvasive predictive biomarker for the poststroke penumbra with clinical translational potential is still lacking. We aim to investigate whether the CircOGDH (circular RNA derived from oxoglutarate dehydrogenase) is a potential biomarker for penumbra in patients with AIS and its role in ischemic neuronal damage. METHODS: CircOGDH was screened from penumbra of middle cerebral artery occlusion mice and was assessed in plasma of patients with AIS by quantitative polymerase chain reaction. Magnetic resonance imaging was used to examine the penumbra volumes. CircOGDH interacted with miR-5112 (microRNA-5112) in primary cortical neurons was detected by fluorescence in situ hybridization, RNA immunoprecipitation, and luciferase reporter assay. Adenovirus-mediated CircOGDH knockdown ameliorated neuronal apoptosis induced by COL4A4 (Gallus collagen, type IV, alpha IV) overexpression. Transmission electron microscope, nanoparticle tracking analysis, and Western blot were performed to confirm exosomes. RESULTS: CircOGDH expression was dramatically and selectively upregulated in the penumbra tissue of middle cerebral artery occlusion mice and in the plasma of 45 patients with AIS showing a 54-fold enhancement versus noncerebrovascular disease controls. Partial regression analysis revealed that CircOGDH expression was positively correlated with the size of penumbra in patients with AIS. Sequestering of miR-5112 by CircOGDH enhanced COL4A4 expression to elevate neuron damage. Additionally, knockdown of CircOGDH significantly enhanced neuronal cell viability under ischemic conditions. Furthermore, the expression of CircOGDH in brain tissue was closely related to that in the serum of middle cerebral artery occlusion mice. Finally, we found that CircOGDH was highly expressed in plasma exosomes of patients with AIS compared with those in noncerebrovascular disease individuals. CONCLUSIONS: These results demonstrate that CircOGDH is a potential therapeutic target for regulating ischemia neuronal viability, and is enriched in neuron-derived exosomes in the peripheral blood, exhibiting a predictive biomarker of penumbra in patients with AIS.

A critical review of pollutant emission factors from fuel combustion in home stoves.

A large population does not have access to modern household energy and relies on solid fuels such as coal and biomass fuels. Burning of these solid fuels in low-efficiency home stoves produces high amounts of multiple air pollutants, causing severe air pollution and adverse health outcomes. In evaluating impacts on human health and climate, it is critical to understand the formation and emission processes of air pollutants from these combustion sources. Air pollutant emission factors (EFs) from indoor solid fuel combustion usually highly vary among different testing protocols, fuel-stove systems, sampling and analysis instruments, and environmental conditions. In this critical review, we focus on the latest developments in pollutant emission factor studies, with emphases on the difference between lab and field studies, fugitive emission quantification, and factors that contribute to variabilities in EFs. Field studies are expected to provide more realistic EFs for emission inventories since lab studies typically do not simulate real-world burning conditions well. However, the latter has considerable advantages in evaluating formation mechanisms and variational influencing factors in observed pollutant EFs. One main challenge in field emission measurement is the suitable emission sampling system. Reasons for the field and lab differences have yet to be fully elucidated, and operator behavior can have a significant impact on such differences. Fuel properties and stove designs affect emissions, and the variations are complexly affected by several factors. Stove classification is a challenge in the comparison of EF results from different studies. Lab- and field-based methods for quantifying fugitive emissions, as an important contributor to indoor air pollution, have been developed, and priority work is to develop a database covering different fuel-stove combinations. Studies on the dynamics of the combustion process and evolution of air pollutant formation and emissions are scarce, and these factors should be an important aspect of future work.

Mass Absorption Efficiency of Black Carbon from Residential Solid Fuel Combustion and Its Association with Carbonaceous Fractions.

Black carbon (BC) emissions, derived primarily from incomplete fuel combustion, significantly affect the global and regional climate. Mass absorption efficiency (MAE) is one important parameter in evaluating the climate impacts of BC. Here, values and variabilities in the MAE of BC (MAEBC) from real-world residential emissions were investigated from a field campaign covering 163 burning events for different fuel-stove combinations. MAEBC (average: 12 ± 5 m2/g) was normally distributed and varied greatly by 2 orders of magnitude. Statistically significant differences in MAEBC were found for various fuels, while no significant differences were observed among different stoves. The fuel difference explained 72 ± 7% of the MAEBC variation. MAEBC did not correlate with the modified combustion efficiency but positively correlated with the ratio of organic carbon (OC) to elemental carbon (EC) and negatively correlated with char-EC. The OC/EC ratio was not always lower in coal emissions in comparison to biomass burning emissions. Coal- and biomass-burning emissions had different profiles of carbon fractions. Char-EC, OC, OC/EC, and char-EC/soot-EC can explain 68.7% of the MAEBC variation, providing the potential for predicting MAEBC from the carbon fractions, since they are more commonly measured and available.

Contributions of internal emissions to peaks and incremental indoor PM2.5 in rural coal use households.

Indoor air quality is critically important to the human as people spend most time indoors. Indoor PM2.5 is related to the outdoor levels, but more directly influenced by internal sources. Severe household air pollution from solid fuel use has been recognized as one major risk for human health especailly in rural area, however, the issue is significantly overlooked in most national air quality controls and intervention policies. Here, by using low-cost sensors, indoor PM2.5 in rural homes burning coals was monitored for ~4 months and analyzed for its temporal dynamics, distributions, relationship with outdoor PM2.5, and quantitative contributions of internal sources. A bimodal distribution of indoor PM2.5 was identified and the bimodal characteristic was more significant at the finer time resolution. The bimodal distribution maxima were corresponding to the emissions from strong internal sources and the influence of outdoor PM2.5, respectively. Indoor PM2.5 was found to be correlated with the outdoor PM2.5, even though indoor coal combustion for heating was thought to be predominant source of indoor PM2.5. The indoor-outdoor relationship differed significantly between the heating and non-heating seasons. Impacts of typical indoor sources like cooking, heating associated with coal use, and smoking were quantitatively analyzed based on the highly time-resolved PM2.5. Estimated contribution of outdoor PM2.5 to the indoor PM2.5 was ~48% during the non-heating period, but decreased to about 32% during the heating period. The contribution of indoor heating burning coals comprised up to 47% of the indoor PM2.5 during the heating period, while the other indoor sources contributed to ~20%. The study, based on a relatively long-term timely resolved PM2.5 data from a large number of rural households, provided informative results on temporal dynamics of indoor PM2.5 and quantitative contributions of internal sources, promoting scientific understanding on sources and impacts of household air pollution.

Spatially Resolved Emission Factors to Reduce Uncertainties in Air Pollutant Emission Estimates from the Residential Sector.

The residential sector is a major source of air pollutant emission inventory uncertainties. A nationwide field emission measurement campaign was conducted in rural China to evaluate the variabilities of realistic emission factors (EFs) from indoor solid fuel combustion. For a total of 1313 burning events, the overall average EFs (±standard deviation) of PM2.5 were 8.93 ± 6.95 and 7.33 ± 9.01 g/kg for biomass and coals, respectively, and 89.3 ± 51.2 and 114 ± 87 g/kg for CO. Higher EFs were found from burning of uncompressed straws, while lower EFs were found from processed biomass pellets, coal briquettes, and relatively clean anthracite coals. Modified combustion efficiency was found to be the most significant factor associated with variations in CO EFs, whereas for PM2.5, fuel and stove differences determined its variations. Weak correlations between PM2.5 and CO indicated high uncertainties in using CO as a surrogate for PM2.5. EFs accurately fit log-normal distributions, and obvious spatial heterogeneity was observed attributed to different fuel-stove combinations across the country. Emission estimation variabilities, which are determined by the interquartile ranges divided by the median values, were notably reduced when spatially resolved EFs were adopted in the inventory.

Optically Measured Black and Particulate Brown Carbon Emission Factors from Real-World Residential Combustion Predominantly Affected by Fuel Differences.

Residential solid fuel use is an important source of black carbon (BC) but also a main source of uncertainty in BC emission inventories, as reliable real-world emission factors (EFs) and data on consumption of noncommercial household fuels are limited. In this study, particulate BC and brown carbon (BrC) for real-world indoor coal and biomass burning were evaluated using a SootScan model OT21 optical transmissometer from a field campaign including 343 biomass/coal combustion events. The highest BC EF from the burning of coal cake (a mixed fuel locally made from coal and clay) was 1.6-6.4 higher than that of other fuels, and BC EFs were higher for coal combustion than for biomass burning. The highest particulate BrC EF was from charcoal burning and was 1.5-4.3 times higher than that from other biomass and coals. Burning fuel in iron stoves had lower BC and BrC EFs, at approximately 15-66% and 40-54%, respectively, compared with burning in other stove types. The difference between heating and cooking activities was statistically insignificant (p > 0.05). A generalized linear model coupled with dominance analysis evidenced that the EFs were significantly associated with fuel and stove types, with the fuel difference being a major influencing factor explaining 68% of the variation. This suggests that a clean fuel transition would have beneficial impacts on air pollution associated with the residential sector in China. The absorption EFs differed by 2-3 orders of magnitude across different fuel-stove combinations. The Absorption Ångström Exponent values for the particulate from residential solid fuel combustions ranged from 0.92 to 3.7.

[Pollution Characteristics and Occupational Exposure Risk of Heavy Metals in Indoor and Outdoor Ambient Particles at a Scaled Electronic Waste Dismantling Plant, Northwest China].

Atmospheric particle samples (PM1.0、PM2.5、PM10) were collected from three sampling sites (indoor and outdoor workplaces of a formal e-waste dismantling plant, and upwind area) in an arid area of Northwest China. The contents of six heavy metals (Cd, Cr, Cu, Ni, Pb, and Zn) were analyzed using ICP-OES. Based on this data, the concentration levels, size distribution characteristics, and occupational exposure risks of heavy metals at the indoor and outdoor dismantling workplaces were studied. Particle analysis showed that Zn (4890 ng·m-3 indoors, 1245 ng·m-3 outdoors)、Pb (indoors 1201 ng·m-3, outdoors 240 ng·m-3), and Cu (indoors 1200 ng·m-3, outdoors 110 ng·m-3) showed higher pollution levels indoors and outdoors at the dismantling workplace. Moreover, the indoor concentration was much higher than that outdoors, indicating that the dismantling activity was the main cause of the high levels of heavy metal contamination. The indoor and outdoor air pollution characteristics were closely related to the types of electronic waste dismantled. Occupational exposure risk assessments showed that the total non-carcinogenic hazard quotient (HQ) of the indoor and outdoor dismantling workshops was 1.62×10-3, and 3.60×10-4, respectively, and the carcinogenic risk values were 2.69×10-7 and 2.59×10-9. Cd caused the greatest carcinogenic and non-carcinogenic risks at both indoor and outdoor dismantling workplaces, but it was still far below the limits (1.0) and acceptable ranges (1×10-6) stipulated by U.S. EPA, indicating that the health risks caused by heavy metals were minor or negligible. Heavy metals in the ambient particulate matter released from an adequately equipped and formally managed e-waste dismantling plant would not lead to any public health risk. The sedimentation characteristics of particulate heavy metals in different organs of the human respiratory system exhibited that the smaller the particle size was, the greater the proportion of deposition in the depths of the respiratory system was. Enterprises should make scientific and effective decisions on the respiratory health risks caused by such fine particles to the health of professional workers.

Spatiotemporal variation of atmospheric nitrated polycyclic aromatic hydrocarbons in semi-arid and petrochemical industrialized Lanzhou City, Northwest China.

Polyurethane foam-based passive air sampler (PUF-PAS) and passive dry deposition sampler (PAS-DD) were adopted, for the first time ever in China, to investigate the atmospheric levels and spatial-temporal distributions of air burdens and dry deposition fluxes of 12 nitrated polycyclic aromatic hydrocarbons (NPAHs) during winter and summer seasons in a multiple site field campaign in a petrochemical industrialized capital city in Northwest China. The results showed that the highest air concentration and dry deposition fluxes of ∑12NPAHs occurred at a heavy traffic site among 18 sampling sites in both winter and summer season. The lowest air concentration and dry deposition fluxes were observed at the background site. The mean concentrations of ∑12NPAHs in the ambient air were 8.6 ± 8.1 ng m-3 in winter and 15 ± 11 ng m-3 in summer. The mean dry deposition fluxes of ∑12NPAHs were 1.8 × 103 ± 1.9 × 103 ng (m2 day)-1 in winter and 1.4 × 103 ± 1.3 × 103 ng (m2 day)-1 in summer, respectively. The total concentration of 12 NPAHs was mainly dominated by 1-nitro-naphthalene (1N-NAP) and 2-nitro-naphthalene(2N-NAP) in air, accounting for 32% in winter and 45% in summer of ∑12NPAHs. 7-Nitro-benzo [a] anthracene (7N-BaA) made the largest contribution to dry deposition fluxes of ∑12NPAHs, accounting for 28% in winter and 24% in summer. The ratios of ∑12NPAHs/∑15pPAHs (parent polycyclic aromatic hydrocarbons) were calculated to identify potential sources of NPAHs across the city. The results revealed that the main atmospheric air concentration and dry deposition fluxes of 12 NPAHs could be attributed to the primary emissions in winter and the secondary reaction formation in summer. The sources of primary emissions could be traced back to petrochemical, steel mills, as well as aluminum industries in winter and vehicle exhaust in summer. Higher ∑12NPAH/∑15pPAH concentration ratios in summer indicated that the oxidation of pPAHs contributed to the secondary formation of NPAHs via atmospheric chemical reactions in this petrochemical industrialized mountain-valley city.