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791.
农业面源污染已成为当今世界各国环境污染治理最棘手的难题之一。通过分析无机化肥与面源污染两者之间的关系,以及一些发达国家在农业面源污染方面的法制状况,提出我国应在法律制度层面规范化肥的使用,出台一部化肥综合性立法及完善现有的水资源立法,对缓解我国农业面源污染的严峻局面意义重大。 相似文献
792.
对"专家判断"法、确定性分析方法、基于风险(Risk-based)的方法和风险指引(Risk-informed)方法等安全距离确定方法的发展运用、分析流程、关键要素、优缺点等进行探讨。建议关注确定性分析方法和风险方法研究。对确定性分析方法,建议加强石油化工企业可信事故场景和伤害标准的研究;对基于风险的方法,建议加大风险指引方法的研究,并制定合理的石油化工企业风险标准,以便采取更加科学合理的方法来制定石油化工企业的安全距离。 相似文献
793.
Li Chen Yuming Wang Peiwu Li Yaqin Ji Shaofei Kong Zhiyong Li Zhipeng Bai 《环境科学学报(英文版)》2012,24(7):1251-1258
Advancing the understanding of the spatial aspects of air pollution in the city regional environment is an area where improved methods can be of great benefit to exposure assessment and policy support. We created land use regression (LUR) models for SO2, NO2 and PM10 for Tianjin, China. Traffic volumes, road networks, land use data, population density, meteorological conditions, physical conditions and satellite-derived greenness, brightness and wetness were used for predicting SO2, NO2 and PM10 concentrations. We incorporated data on industrial point sources to improve LUR model performance. In order to consider the impact of different sources, we calculated the PSIndex, LSIndex and area of different land use types (agricultural land, industrial land, commercial land, residential land, green space and water area) within different buffer radii (1 to 20 km). This method makes up for the lack of consideration of source impact based on the LUR model. Remote sensing-derived variables were significantly correlated with gaseous pollutant concentrations such as SO2 and NO2. R2 values of the multiple linear regression equations for SO2, NO2 and PM10 were 0.78, 0.89 and 0.84, respectively, and the RMSE values were 0.32, 0.18 and 0.21, respectively. Model predictions at validation monitoring sites went well with predictions generally within 15% of measured values. Compared to the relationship between dependent variables and simple variables (such as traffic variables or meteorological condition variables), the relationship between dependent variables and integrated variables was more consistent with a linear relationship. Such integration has a discernable influence on both the overall model prediction and health effects assessment on the spatial distribution of air pollution in the city region. 相似文献
794.
795.
796.
Aliphatic hydrocarbons (n-alkanes) associated with fine particulate matter were determined in the ambient air of urban, industrial
and coastal areas in Tianjin, China, where intensive coal burning for industrial and domestic purpose takes place. n-Alkane homologues
from C12 to C35 were quantifiable in all samples with C20–C31 being the most abundant species. Average concentrations of the total
n-alkanes were 148.7, 250.1 and 842.0 ng/m3 in July, April and January, respectively. Seasonal variations were mainly attributed to
ambient temperature changes and coal combustion for residential heating. Among the three studied areas, the highest levels of n-alkanes
were observed in the industrial complex in winter and spring, but in summer the coastal alkane concentration moved up to the highest.
A mono-modal distribution for n-alkanes was observed in spring and summer with odd carbon number predominance and a maximum
centered at C27–C31, suggesting the release of plant wax into the atmosphere. The bimodal distribution with maxima at C22 and C26
observed in winter indicated a substantial influence of fossil fuel sources. All the CPIs (CPI1, CPI2, CPI3) values, varying between
0.64 and 1.97, indicated the influence of anthropogenic emissions on fine organic aerosols. The estimated contributions of plant wax to
total n-alkanes were on average of 12.9%, 19.1% and 26.1% for winter, spring and summer, respectively. 相似文献
797.
Li Chen Zhipeng Bai Shaofei Kong Bin Han Yan You Xiao Ding Shiyong Du Aixia Liu 《环境科学学报(英文版)》2010,22(9):1364-1373
Land use regression (LUR) model was employed to predict the spatial concentration distribution of NO2 and PM10 in the Tianjin
region based on the environmental air quality monitoring data. Four multiple linear regression (MLR) equations were established based
on the most significant variables for NO2 in heating season (R2 = 0.74), and non-heating season (R2 = 0.61) in the whole study area;
and PM10 in heating season (R2 = 0.72), and non-heating season (R2 = 0.49). Maps of spatial concentration distribution for NO2 and
PM10 were obtained based on the MLR equations (resolution is 10 km). Intercepts of MLR equations were 0.050 (NO2, heating season),
0.035 (NO2, non-heating season), 0.068 (PM10, heating season), and 0.092 (PM10, non-heating season) in the whole study area. In the
central area of Tianjin region, the intercepts were 0.042 (NO2, heating season), 0.043 (NO2, non-heating season), 0.087 (PM10, heating
season), and 0.096 (PM10, non-heating season). These intercept values might imply an area’s background concentrations. Predicted
result derived from LUR model in the central area was better than that in the whole study area. R2 values increased 0.09 (heating
season) and 0.18 (non-heating season) for NO2, and 0.08 (heating season) and 0.04 (non-heating season) for PM10. In terms of R2,
LUR model performed more e ectively in heating season than non-heating season in the study area and gave a better result for NO2
compared with PM10. 相似文献
798.
介绍了“基于HAZOP的保护层分析技术”的工艺安全管理新模式。在此基础上,利用该方法对水煤浆气化装置进行了分析,识别出了装置存在的重大工艺危险,提出对策建议,对整个装置重大工艺安全事故的预防提供了有力的技术支持。 相似文献
799.
本文以中秦岭地区为滑坡易发性评价对象,针对研究区的情况,选取了坡度、起伏度、地貌类型、岩性、土壤侵蚀强度、活动断裂距、地震动参数、地下水类型、多年平均降雨量9个评价因子,建立了研究区滑坡易发性评价的数据库。运用单因子概率比率模型对各因子和滑坡的相关性进行了评价,揭示了该区滑坡灾害类型特点及空间分布规律,明确了中秦岭地区滑坡地质灾害的极高易发、高易发三大聚集地区的位置。 相似文献
800.
本文以甘肃省北峪河流域的三家地滑坡、红土坡滑坡、曾家街滑坡作为主要研究对象,通过对上述三个典型滑坡的野外实地测量,结合对当地民众的走访以及在当地政府部门获取的相关数据,归纳分析得出该地区滑坡灾害的主要诱发因素,及其给人们带来的影响。 相似文献