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Abstract: Due to the high costs and deployment difficulties associated with automated sampling technologies, few investigations have been published on atmospheric mercury in typical urban and rural areas in developing countries. In this study, a novel passive sampler for gaseous elemental mercury was developed and applied to characterize trends in atmospheric mercury levels across an urban–rural transect. The sampling transect originated in the city of Beijing and extended ∼150km southward into a rural region. Field deployment was conducted during September–October (autumn) and November–December (winter) in 2010. The mercury concentrations in air obtained using the passive sampler were consistent with synchronous automated measurements performed during the field deployment. The results demonstrated that atmospheric mercury concentrations increased along the urban–rural gradient in the following order in both of the two periods: urban>suburban>rural (populated)>rural (farmland). [Copyright &y& Elsevier]

Abstract: Objection: To study the pollution of atmospheric particles at winter in Beijing and compare the lung toxicity which induced by particle samples from different sampling sites. Method: We collected samples from two sampling points during the winter for toxicity testing and chemical analysis. Wistar rats were administered with particles by intratracheal instillation. After exposure, biochemically index, esimmunity indexes, histopathology and DNA damage were detected in rat pulmonary cells. Result: The elements with enrichment factors (EF) larger than 10 were As, Cd, Cu, Zn, S and Pb in the four experiment groups. The priority control of the total concentration of polycyclic aromatic hydrocarbons (PAHs) in PM10 and PM2.5 of Near-traffic source was much higher than that of Far-traffic source, it demonstrated that near the traffic source of PAHs pollution was heavier than that of Far-traffic source, as it was close to main roads Beiyuan Road, motor vehicle emissions were much higher. The pathology of lung showed that the degree of inflammation was increased with the particle diameter minished, it was the same as the detection of biochemical parameters such as lactate dehydrogenase (LDH), Total antioxidant status(T-AOC) and total protein (TP) in BALF and inflammation cytokine(interleukin-1, interleukin-6 and tumor necrosis factor-alpha) in lung homogenate. The indexes of DNA damage including the content of DNA and Olive empennage of PM2.5 were significant higher than that of PM10 at the same surveillance point (P < 0.05), near-traffic particles were higher than the far-traffic particles at the same diameter, (P < 0.05). Conclusion: Near-traffic area particles had certain pollution at winter in Beijing. Meanwhile, atmospheric particulate matters on lung toxicity were related to the particles size and distance related sites which were exposed: smaller size, more toxicity; nearer from traffic, more toxicity. [Copyright &y& Elsevier]

Abstract: Concentrations of OCPs in rain, canopy throughfall, and runoff water were measured in the Beijing metropolitan area during the rainy seasons from 2006 to 2007. This study was conducted to calculate the fluxes of OCPs in rain and canopy throughfall, as well as their contributions to runoff. At urban sites, the contribution of HCB and ΣHCHs from rainfall accounted for approximately 50% of the mass in runoff. At the site with significant coverage of landscaping trees, the HCB, ΣHCHs, and ΣDDTs from the net canopy throughfall accounted for approximately 10% of the mass in the runoff. Based on the data obtained in this study, loadings of OCPs (in μg) in rain, net canopy throughfall, and runoff water were calculated. The input of OCPs from rain and canopy throughfall water accounted for a significant portion of urban runoff. In cities undergoing rapid urban sprawl, monitoring and control of the transport of OCPs in urban runoff are essential for effective control of environmental hazards in surface water bodies. [ABSTRACT FROM AUTHOR]

Abstract: Much rain and strong winds caused by a cold front occurred in Beijing during the period of Sep. 27 to Oct. 4, 2004 and led to sharp drops in maximum and mean concentrations of HONO, HCHO, O3, and NO2, i.e., the maximum concentrations were reduced by 5.9, 21.3, 45.6, and 44.4 ppb, respectively, and the mean concentrations were decreased by 4.0, 5.5, 30.3, and 32.3 ppb, respectively. For daily HO x production rates HONO photolysis was the largest contributor and over 90% contributions were from photolysis of HONO and HCHO. Large number and area percentages of soot aggregate from PM10, and high correlations between concentrations of PM10 and chemical formation of HONO suggested that heterogeneous reactions of NO2 on surfaces of soot aggregate could be a key source of HONO in the heavy traffic areas of Beijing during the night and should be considered in air quality simulations for such areas. [Copyright &y& Elsevier]

Analyses the importance-performance of Beijing as an international meeting destination. Brief review of Beijing's conference industry; Methods used in the study; Results of the study; Conclusion about the factors considered in selecting a city as a meeting destination.

• Proposed a technical framework for ecological restoration zoning from the hydro-ecological perspective. • Proposed an zoning method which embedding landscape pattern models and hydrological models. • Emphasis on dynamic evolution process of hydro-ecology. • There is significant improvement of hydro-ecology and the regional differentiation was enlarged during 2000–2022. To prevent the degradation and destruction of ecosystems, ecological restoration has become a worldwide issue. In recent years, China has been comprehensively carrying out relevant work on national spatial ecological restoration planning, among which the work on ecological restoration zoning can provide strong support for the implementation of ecological restoration strategies. We propose a theoretical framework and technical route for ecological restoration zoning from the hydro-ecological perspective, and suggest forming a regional ecological restoration zoning system based on the watershed as the basic unit and the dynamic evolution process of hydro-ecology as the core. We conduct an empirical study in Yanqing District, Beijing. The results show that: (i) From 2000 to 2022, the hydro-ecological comprehensive index of Yanqing District shows an upward trend. In terms of spatial pattern changes, it roughly shows a rising trend in the northeastern and southern mountainous areas, and a downward trend in the central-western and southwestern basins. (ii) Six types of ecological restoration zones are formed with the watershed as the basic unit. Zone Ⅰ accounts for the largest area (26.87%), and Zone Ⅵ accounts for the smallest proportion (7.14%). (iii) The proportion of areas with good or superior hydro-ecology in the Ecological Policy Zone of Yanqing District increased by 15.89% from 2000 to 2022, which is significantly higher than the average level, confirming the effectiveness of ecological policies such as nature reserves. This study provides a paradigm for ecological restoration zoning from the hydro-ecological perspective, and provides assistance for regional ecological restoration and sustainable development in China and even globally. [ABSTRACT FROM AUTHOR]

From 1990 to 2017, the number of vehicles in China increased sharply from 5 million to 310 million, and vehicle emissions became one of the major sources of air pollution. Among the main sources of PM 2.5 in Beijing, the contributions from vehicle sources increased from 5.6% (2000) to 31.1% (2012) to 45% (2017). In 2010, the CO, hydrocarbon (HC), NO x , and particulate matter (PM) emissions of yellow-label vehicles (YLVs) accounted for 46.1%, 47.9%, 63.1% and 86.1% of the total emissions from on-road vehicles. In recent years, China has been implementing a YLV scrappage subsidy policy to control air pollution, and this policy has cost several hundred billion yuan nationwide. However, China has not evaluated the costs and benefits of the policy. Many people question whether the YLV scrappage subsidy policy is worthwhile, but all the stakeholders involved complicate the process of accurately evaluating the true value of the policy. In this study, we evaluated and compared the costs and benefits of the policy in the Beijing-Tianjin-Hebei (BTH) region based on 1.362 million YLVs from 2008 to 2015. Because of the implementation of the policy, the PM 2.5 , PM 10 , NO x , CO and HC emissions in the BTH region decreased by 16.46, 18.12, 174.44, 669.11, and 91.64 kt, respectively, in 2008–2015. The results show that the policy played an important role in reducing pollutant emissions and improving environmental quality in the BTH region. The costs, benefits, and net benefits of the policy were 13.69, 34.03, and 20.34 billion yuan , respectively. The cost-benefit ratio in the BTH region was 1:2.49; at the city scale, Beijing ranked first (1:7.27), and the cost-benefit ratios of Tianjin and Hebei Province were 1:2.06 and 1:1.14, respectively. Of the 13 cities in the BTH region, Beijing had the highest net benefits, amounting to 16.43 billion yuan , while Handan City has the lowest net benefits, amounting to −0.58 billion yuan. The results may provide scientific support for the promotion of older vehicle and diesel vehicle scrappage subsidy policies, the development of cost-benefit analysis (CBA), and effective environmental decision-making in China. • Based on net number of scrappage YLVs, net benefits of the policy are calculated. • This paper estimates costs and benefits of the policy based on 1.27 million YLVs. • The costs, benefits, and net benefits are 13.69, 34.03, and 20.34 billion yuan. • The results help China promote vehicle scrappage subsidy policy on a large scale. • The results promote the development of the cost-benefit analysis in China. [ABSTRACT FROM AUTHOR]

Background Vaccination of infants beginning at birth is recommended to prevent Hepatitis B virus (HBV) infection in China. Compared to 5 μg/dose vaccine administered in other regions in China, a three-dose HB recombinant yeast vaccine at 10 μg/dose has been administered for infants within 24 h after birth, 1 month and 6 months of age in Beijing since 2006. In a community-based retrospective cohort study, factors influencing immunologic vaccine response were evaluated. Methods A total of 3670 infants who completed a 3-dose 10 μg recombinant HB vaccine regimen and born to hepatitis B antigen negative mothers were included. The effect on anti-HBs titers of maternal nutrient status, infants’ birth condition, growth factors, timeliness of vaccination, dosing interval and the interval until post-vaccination serologic testing (PVST) were evaluated. Results A total of 3666 infants with no markers of HBV infection were included in analysis. The mean anti-HB titers were 1767.17 mIU/ml. Only 16.9% of the infants completed their PVST within 30–59 days after the final dose of vaccination. Multivariate linear regression analysis showed that delay in PVST ( β = −0.097, p < 0.0001) and maternal folic acid supplementation ( β = 0.067, p = 0.002) were associated with log-transformed anti-HB titers. Also a trend toward significant association was observed between the calcium supplementation of infants and log-transformed anti-HBs titers ( β = 0.062, p = 0.057). Longer interval between dose 2 and dose 3 was not observed to increase the anti-HB titers after cofactors adjustment. Conclusions Our findings illustrate the importance of timing of PVST to avoid unnecessary revaccination. Multi-center large cohort studies should verify the effect and magnitude of folate and calcium supplementation on HB vaccine response. [ABSTRACT FROM AUTHOR]

Fine particulate matter (PM 2.5 ) has attracted increasing attention due to its impacts on air quality and human health. As an important source of PM 2.5 , diesel vehicles are often the focus of research. In this study, we characterized the carbonaceous composition of PM 2.5 that is emitted from on-road China III diesel trucks (DTs). Organic carbon (OC), elemental carbon (EC), and PM 2.5 emission characteristics were determined for 17 China III DTs, including 6 light-duty diesel trucks (LDDTs), 5 medium-duty diesel trucks (MDDTs), and 6 heavy-duty diesel trucks (HDDTs), based on real-world measurements in Beijing, China, using a portable emissions measurement system (PEMS). The average distance-based PM 2.5 emission factors (EFs) (g km −1 ) generally increased and the average CO 2 -based PM 2.5 EFs (g (kg of CO 2 ) −1 ) generally decreased with increased vehicle size from LDDTs to MDDTs to HDDTs. The effects of driving conditions on the EFs for carbonaceous PM 2.5 were analyzed. The results show that distance-based and CO 2 -based EFs strongly depend on driving conditions. Generally, greater amounts of PM 2.5 and OC are emitted from non-highway driving cycles, and greater amounts of EC are emitted from highway driving cycles for vehicles of the same size. For LDDTs, MDDTs, and HDDTs, no significant differences were observed between vehicles with different EC/OC ratios; therefore, the EC/OC ratio is not useful for distinguishing between the emissions generated by differently sized vehicles. The EC/OC, OC/PM 2.5 , and EC/PM 2.5 mass ratios are strongly dependent on driving conditions for vehicles of the same size. The results of this study provide EFs for the carbonaceous composition of PM 2.5 that are more appropriate for China; these results will be helpful for improving policies that are designed to control the carbonaceous composition of PM 2.5 emitted from on-road DTs in China. [ABSTRACT FROM AUTHOR]

Abstract: Incorporated into the WRF–Chem model are the three HONO sources, i.e., the reaction of photo-excited NO2 with water (NO2 * chemistry), heterogeneous reactions on aerosol surfaces, and HONO emissions. Four case simulations were performed in Beijing, Tianjin, and Hebei Province (BTH region) in August of 2007. Results indicate that the NO2 * chemistry yields 30–50 ppb enhancements in daily maximum 1-h surface O3 concentrations in major cities and 3–10 ppb increases in monthly mean daily maximum 8-h surface O3 concentrations in most areas of the BTH region. Heterogeneous reactions on aerosol surfaces lead to 5–20 ppb decreases in monthly mean NOy concentrations in major cities over the BTH region. Heterogeneous reactions and HONO emissions are the largest, and the second largest contributor, accounting for ∼59% and 26% of simulated HONO concentrations, respectively. The three HONO sources produce enhancements in monthly mean daytime (10:00–17:00) concentrations of NOy (total reactive N-containing compounds), NO2, HNO3, HONO, and HOx being −1 to −5 ppb, −1 to −3 ppb, −0.3 to 0.5 ppb, 20–50 ppt, and 1–3 ppt, respectively. Comparison with observations shows that inclusion of the three HONO sources into the WRF–Chem model can considerably improve HONO and O3 simulations in the BTH region. For HONO the mean, the normal mean bias, the root mean square error, and the correlation coefficient is greatly improved from 0.04 to 0.56 ppb, from −97% to −39%, from 1.10 ppb to 0.51 ppb, and from −0.56 to 0.86, respectively, by comparison with the gas chemical mechanism only considered in the WRF–Chem model. This suggests that the three important HONO sources be included in air quality models, particularly in the areas with high emissions of NOx and particulate matter. [Copyright &y& Elsevier]

This paper presents a mathematical model to determine both a worker's decision to participate in a nonwork activity and the decision about whether to include it in the basic home-work-home commute. By using household travel survey data from Beijing, China, this paper presents an empirical analysis framework to examine commuters' nonwork stop-making behavior in a highly urbanized environment in a developing country. To account for the censored nature of the decision about whether to include a nonwork stop in the commute tour, a bivariate probit selection model was used. To enhance the behavioral basis for the model, extensive statistical tests were performed on model specifications and assumptions. The empirical results provide useful insights into the effects of individual/household sociodemographics, transportation measures, work schedule, and mode choice on commuters' nonwork stop-making propensity. This study also provides methodological evidence that could lead to an approach for predicting the changes in commuters' nonwork stop-making behavior as a result of the changes in sociodemographics and transportation scenarios. [ABSTRACT FROM AUTHOR]

Abstract: Fulvic acids from the soil of Peking University (PF) and a Nordic river (NF) were separated into well defined sub-fractions using sequential elution techniques based on eluent polarity. The chemical properties of the fractions including: PF1 and NF1 (eluted by 0.01M HCl), PF2 and NF2 (eluted by 0.01M HCl+20% methanol), PF3 and NF3 (eluted by 0.01M HCl+40% methanol), and PF4 and NF4 (eluted by 100% methanol), were characterized using UV–Visible spectroscopy, elemental analysis and 13C NMR. The results showed that the UV absorptions of the elution peaks at 280nm (A280) increased from PF2 to PF4 and NF2 to NF4. No elution peaks were observed for PF1 and NF1. The carbon contents increased from 43.34% to 51.90% and 43.06% to 53.26% while the oxygen contents decreased from 46.39% to 36.76% and 49.76% to 40.03% for PF1–PF4 and NF1–NF4, respectively. As a polarity indicator, the (O+N)/C ratio for PF1–PF4 and NF1–NF4 decreased from 0.88 to 0.62 and 0.89 to 0.58, respectively. The aromatic carbon content increased from PF1 to PF4 and NF1 to NF4, suggesting an increase of the hydrophobicity of these fractions. The polarity was positively related to the ratio of UV absorption at 250nm and 365nm (E2/E3), and negatively related to the aromaticity. A high positive relationship between the aromaticity and E2/E3 of fulvic acid fractions was also obtained. The use of an eluent with a decreasing polarity allowed to providing simpler fractions of soil and aquatic fulvic acids. [Copyright &y& Elsevier]

Measurements of nitrous acid (HONO) and nitrogen dioxide (NO_2) in Beijing City have been performed by means of a developed differential optical absorption spectroscopy (DOAS) system based on photodiode array (PDA), during the autumn of 2004. HONO and NO_2 were simultaneously identified by their characteristic absorption bands in the spectral region between 337 nm and 372 nm with high sensibility and time resolution. The concentrations of HONO exhibit obviously diurnal variation with a nocturnal maximum and a daytime minimum. The highest HONO value up to 11.8 μg/m^3 was observed during the night of 2/3 September. Possible sources of the observed HONO were discussed. Good correlation to NO_2 indicates that NO2 is a main source component. The measurement also shows direct emission of HONO is an important source in strongly polluted urban area. [ABSTRACT FROM AUTHOR]

Provinces that provide emission-intensive products now are facing huge financial pressure to control regional air pollutant emissions. Assessing the actual regional air emission abatement costs of each province from the consumer perspective can help to clarify regional pollution abatement responsibilities and formulate sound monetary compensation policies between consumers and producers in China. In this study, we employ a multiregional input-output model to estimate the total air pollution abatement costs and economic benefits caused by interregional trade for each region in 2012. The results indicate that regions with higher GDP per capita, such as the Beijing-Tianjin, East Coast, and South Coast regions, outsourced total pollution abatement costs (TPAC) for air emissions to undeveloped central and western regions via interregional trade within China. Based on a comparison of the cost-benefit index among regions, wealthy regions left nearly 80% of their consumption-based value added locally but outsourced more than 50% of their consumption-based TPAC to other regions, especially to northwestern and central regions with lower GDP per capita. Such a mismatch necessitates in-depth cross-boundary collaboration for control of air pollutant emissions in regions suffering terrible haze problems, such as the North China Plain. • Regional air emission abatement costs embodied in interregional trade are assessed. • Central, Northwest, and North regions have higher production-based TPAC nationwide. • Developing regions suffered more air emission control costs from developed regions. • Shanxi suffered the highest inequity when trading with Beijing nationwide. [ABSTRACT FROM AUTHOR]