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The growth pattern and fuel life cycle analysis of the electricity consumption of Hong Kong Texte intégral
2012
To, W.M. | Lai, T.M. | Lo, W.C. | Lam, K.H. | Chung, W.L.
As the consumption of electricity increases, air pollutants from power generation increase. In metropolitans such as Hong Kong and other Asian cities, the surge of electricity consumption has been phenomenal over the past decades. This paper presents a historical review about electricity consumption, population, and change in economic structure in Hong Kong. It is hypothesized that the growth of electricity consumption and change in gross domestic product can be modeled by 4-parameter logistic functions. The accuracy of the functions was assessed by Pearson's correlation coefficient, mean absolute percent error, and root mean squared percent error. The paper also applies the life cycle approach to determine carbon dioxide, methane, nitrous oxide, sulfur dioxide, and nitrogen oxide emissions for the electricity consumption of Hong Kong. Monte Carlo simulations were applied to determine the confidence intervals of pollutant emissions. The implications of importing more nuclear power are discussed.
Afficher plus [+] Moins [-]To what extent do molecular collisions arising from water vapour efflux impede stomatal O₃ influx? Texte intégral
2012
Uddling, Johan | Matyssek, Rainer | Pettersson, Jan B.C. | Wieser, Gerhard
Pre-requisite for reliable O₃ risk assessment for plants is determination of stomatal O₃ uptake. One unaddressed uncertainty in this context relates to transpiration-induced molecular collisions impeding stomatal O₃ influx. This study quantifies, through physical modelling, the error made when estimating stomatal O₃ flux without accounting for molecular collisions arising from transpiratory mass flow of gas out of the leaf. The analysis demonstrates that the error increases with increasing leaf-to-air water vapour mole fraction difference (Δw), being zero in water vapour saturated air and 4.2% overestimation at Δw of 0.05. Overestimation is approximately twice as large in empirical studies quantifying stomatal O₃ flux from measured leaf or canopy water flux, if neglecting both water vapour-dry air collisions (causing overestimation of leaf conductance) and collisions involving O₃. Correction for transpiration-induced molecular collisions is thus relevant for both empirical research and for large-scale modelling of stomatal O₃ flux across strong spatial Δw gradients.
Afficher plus [+] Moins [-]The response of rice grain quality to ozone exposure during growth depends on ozone level and genotype Texte intégral
2012
Frei, Michael | Kohno, Yoshihisa | Tietze, Stefan | Jekle, Mario | Hussein, Mohammed A. | Becker, Thomas | Becker, Klaus
The effects of ozone exposure during the cropping season on rice grain quality were investigated in chamber experiments employing four ozone treatments (charcoal filtered air, ambient, 2× ambient, and 2.5× ambient concentration) and six genotypes. The concentrations of protein and lipids in brown rice increased significantly in response to ozone, while starch concentration and thousand kernel mass decreased. Other parameters, including the concentrations of iron, zinc, phenolics, stickiness and geometrical traits did not exhibit significant treatment effects. Total brown rice yield, protein yield, and iron yield were negatively affected by ozone. Numerous genotypic differences occurred in the response to ozone, indicating the possibility of optimizing the grain quality in high ozone environments by breeding. It is concluded that although the concentrations of two important macronutrients, proteins and lipids, increased in ozone treated grains, the implications for human nutrition are negative due to losses in total grain, protein and iron yield.
Afficher plus [+] Moins [-]Ozone weekend effect in Santiago, Chile Texte intégral
2012
Seguel, Rodrigo J. | Morales S., Raúl G.E. | Leiva G., Manuel A.
The study examined weekday–weekend differences in ozone, NOₓ (NO and NO₂) and VOC concentrations in Santiago, Chile, from 1999 to 2007. The results provide evidence for the occurrence of an atmospheric phenomenon that produces higher ozone concentrations during weekends despite lower concentrations of ozone precursors. This phenomenon is known as the weekend effect (WE). The overall ozone decrease since the spring of 2004 was a consequence of the implementation of several urban pollution control measures. Although these measures caused a decline in the number of days that exceed the national standard from two-thirds to one-third of summer days, the WE, which became statistically significant beginning in September 2004, could not be eliminated. Furthermore, VOC/NOₓ ratios decreased during the same period (2004), especially in the most industrialized area of Santiago. Similarly, under these regimes, the VOC/NOₓ ratios were higher on Sundays than on weekdays and caused higher ozone concentrations on Sundays.
Afficher plus [+] Moins [-]Polybrominated diphenyl ethers (PBDEs) in the indoor and outdoor environments – A review on occurrence and human exposure Texte intégral
2012
Besis, Athanasios | Samara, Constantini
Polybrominated diphenyl ethers (PBDEs) constitute an important group of brominated flame retardants that have been massively produced and extensively used in numerous everyday products, providing longer escape times in case of fire and thus saving lives, as well as reducing the damage of property. In recent years, PBDEs have been recognized as significant pollutants of the indoor environment. This article provides a synthesis and critical evaluation of the state of the knowledge about the occurrence of PBDEs in the indoor environment (air and dust in homes, workplaces and cars) in different countries in Europe, North America, Asia and Australia, as well as about the human exposure via indoor air inhalation and dust ingestion in comparison to outdoor air inhalation and dietary intake.
Afficher plus [+] Moins [-]Brominated flame retardants in three terrestrial passerine birds from South China: Geographical pattern and implication for potential sources Texte intégral
2012
Sun, Yu-xin | Luo, Xiao-jun | Mo, Ling | Zhang, Qiang | Wu, Jiang-ping | Chen, She-jun | Zou, Fa-sheng | Mai, Bi-xian
Polybrominated diphenyl ethers (PBDEs), decabromodiphenyl ethane (DBDPE), polybrominated biphenyls (PBBs) and pentabromotoluene (PBT) were investigated in light-vented bulbul (LVB), long-tailed shrike (LTS) and oriental magpie-robin (OMR) collected from seven sampling sites in South China. ∑PBDEs, DBDPE, PBB 153, and PBT levels ranged from 35 to 15 000, no detected (nd)-130, nd-6800, and nd-6.8 ng/g lipid weight, respectively. Positive correlations were found between δ¹⁵N values and brominated flame retardant (BFR) concentrations. The BFR geographic pattern indicated that PBDEs were linked to e-waste recycling and local industry activities as well as urbanization; PBB 153 was derived from e-waste; DBDPE was mainly come from local industry activities; and no specific source was observed for PBT. PBDE congener profiles were found to be depended on bird species and sampling sites with relatively high abundances of lower brominated congeners in e-waste site and significantly higher abundance of BDE153 in LTS and OMR than in LVB.
Afficher plus [+] Moins [-]Pollutant plume delineation from tree core sampling using standardized ranks Texte intégral
2012
Wahyudi, Agung | Bogaert, Patrick | Trapp, Stefan | Macháčková, Jiřina
There are currently contradicting results in the literature about the way chloroethene (CE) concentrations from tree core sampling correlate with those from groundwater measurements. This paper addresses this issue by focusing on groundwater and tree core datasets in CE contaminated site, Czech Republic. Preliminary analyses revealed strongly and positively skewed distributions for the tree core dataset, with an intra-tree variability accounting for more than 80% of the total variability, while the spatial analyses based on variograms indicated no obvious spatial pattern for CE concentration. Using rank transformation, it is shown how the results were improved by revealing the initially hidden spatial structure for both variables when they are handled separately. However, bivariate analyses based on cross-covariance functions still failed to indicate a clear spatial correlation between groundwater and tree core measurements. Nonetheless, tree core sampling and analysis proved to be a quick and inexpensive semi-quantitative method and a useful tool.
Afficher plus [+] Moins [-]Spatial distribution of per- and polyfluoroalkyl compounds in coastal waters from the East to South China Sea Texte intégral
2012
Cai, Minghong | Zhao, Zhen | Yang, Haizhen | Yin, Zhigao | Hong, Qingquan | Sturm, Renate | Ebinghaus, Ralf | Ahrens, Lutz | Cai, Minggang | He, Jianfeng | Xie, Zhiyong
The spatial distribution of per- and polyfluoroalkyl compounds (PFCs) were investigated in coastal waters collected onboard research vessel Snow Dragon from the East to South China Sea in 2010. All samples were prepared by solid-phase extraction and analyzed using high performance liquid chromatography/negative electrospray ionization-tandem mass spectrometry (HPLC/(−)ESI-MS/MS). Concentrations of 9 PFCs, including C₄ and C₈ (PFBS, PFOS) perfluoroalkyl sulfonate (PFSAs), C₅–C₉ and C₁₃ (PFPA, PFHxA, PFHpA, PFOA, PFNA, PFTriDA) perfluoroalkyl carboxylates (PFCAs), and N-ethyl perfluorooctane sulfonamide (EtFOSA) were quantified. The ΣPFC concentrations ranged from 133 pg/L to 3320 pg/L, with PFOA (37.5–1541 pg/L), PFBS (23.0–941 pg/L) and PFHpA (0–422 pg/L) as dominant compounds. Concentrations of PFCs were greater in coastal waters along Shanghai, Ningbo, Taizhou, Xiamen and along coastal cities of the Guangdong province compared to less populated areas along the east Chinese coast. Additionally, the comparison with other seawater PFC measurements showed lower levels in this study.
Afficher plus [+] Moins [-]Environmental risks of trace elements associated with long-term phosphate fertilizers applications: A review Texte intégral
2012
Jiao, Wentao | Chen, Weiping | Chang, Andrew C. | Page, Albert L.
Application of phosphate fertilizer can be a significant contributor of potentially hazardous trace elements such as arsenic, cadmium, and lead in croplands. These trace elements have the potential to accumulate in soils and be transferred through the food chain. We articulated the environmental risks of trace elements associated with long-term phosphate fertilizer applications by combining data from the literature and results from model simulations. Results illustrate that under normal cropping practice, the impact of phosphate fertilizers applications on trace element accumulation in receiving soils has been limited and localized. Their plant uptake varied greatly depending on the fertilizer application rates, soil and plant characteristics. This has led to a great deal of uncertainty in characterizing soil distribution coefficients, Kd, and plant uptake factors, PUF, two of the most used parameters in assessing the risks of accumulations. Therefore, the risks may be more appropriately assessed based on the probabilistic distributions of Kd and PUF.
Afficher plus [+] Moins [-]Occupational exposure to airborne particles and other pollutants in an aviation base Texte intégral
2012
Buonanno, Giorgio | Bernabei, Manuele | Avino, Pasquale | Stabile, Luca
The occupational exposure to airborne particles and other pollutants in a high performance jet engine airport was investigated. Three spatial scales were considered: i) a downwind receptor site, ii) close to the airstrip, iii) personal monitoring. Particle number, surface area, mass concentrations and distributions were measured as well as inorganic and organic fractions, ionic fractions and Polycyclic Aromatic Hydrocarbons. Particle number distribution measured at a receptor site presents a mode of 80 nm and an average total concentration of 6.5 × 10³ part. cm⁻³; the chemical analysis shows that all the elements may be attributed to long-range transport from the sea. Particle number concentrations in the proximity of the airstrip show short term peaks during the working day mainly related to takeoff, landing and pre-flight operations of jet engines. Personal exposure of workers highlights a median number concentration of 2.5 × 10⁴ part. cm⁻³ and 1.7 × 10⁴ part. cm⁻³ for crew chief and hangar operator.
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