大气杀手——酸雨

酸雨 ,顾名思义 ,就是大气中的硫氧化物、氮氧化物等溶于纯净的雨水中 ,使雨水具有弱酸性 ,即谓之酸雨。如果说 ,十多年前 ,酸雨还只是个别国家的局部性问题 ,那么随着各国矿物燃料消耗量的不断增加 ,排入大气中的二氧化碳、硫氧、氮氧化物等日渐增多 ,目前酸雨的危害已向全世界蔓延 ,并成为当代世界的重大环境问题之一。硫氧化物和氮氧化物来源于何处呢 ?一是自然来源。如火山喷发时 ,就有二氧化硫的喷出 ;沼泽、土壤、坑道等地的含硫物质 ,在厌气细菌的作用下 ,会以硫化氢的形式释放出来 ,经周围环境的氧化后 ,生成二氧化硫 ;沉积在海洋中…     

Vertical Observations and Analysis of PM2.5, O3, and NOx at Beijing and Tianjin from Towers during Summer and Autumn 2006

During the period between 18 August and 22 September 2006, an ultraviolet photometric O3 analyzer, a NO-NO2-NOx chemiluminescence analyzer, and a quartz micro-oscillating-scale particle concentration analyzer were simultaneously used for monitoring at three different heights each at Beijing (325-m tower) and Tianjin (255-m tower). These towers belong to the Institute of Atmospheric Physics (IAP) of the Chinese Academy of Sciences (CAS) and to the Tianjin Municipal Meteorological Bureau, respectively. These measurements were used to continuously measure the atmospheric O3 and NOx volume-by-volume concentrations and the PM2.5 mass concentration within a vertical gradient. When combined with meteorological data and information on the variation of vertical characteristics of the various atmospheric pollutants in the two cities, analysis shows that these two cities were seriously polluted by both PM2.5 and O3 during summer and autumn. The highest daily-average concentrations of PM2.5 near the ground in Beijing and Tianjin reached 183 μg m-3 and 165 μg m-3, respectively, while the O3 concentrations reached 52 ppb and 77 ppb, and NOx concentrations reached 48 ppb and 62 ppb for these two cities, respectively. The variations in the daily-average concentrations of PM2.5 between Beijing and Tianjin were demonstrated to be consistent over time. The concentrations of PM2.5 measured in Beijing were found to be higher than those in Tianjin. However, the overall O3 concentrations near the ground in Tianjin were higher than in Beijing. NOx concentrations in Tianjin were consistently lower than in Beijing. It was also found that PM2.5 pollution in Beijings atmosphere may also be affected by the pollutants originating in and delivered from Tianjin, and that Ti     

成都地区闪电产生氮氧化物的观测研究

为了解四川盆地闪电产生的NOX向低空的传输特征,利用大气平均电场仪、氮氧化物分析仪、臭氧分析仪对成都地区雷暴过程中闪电产生的NOX进行了地面观测,并结合风廓线雷达测得的地面0.4km的风速风向数据进行了分析。研究结果表明:(1)、NOX浓度随时间的变化与NO浓度随时间的变化呈正相关关系,O3的浓度随时间的变化与NOX的浓度随时间变化呈负相关关系;(2)、雷暴过程中,NOX和NO的浓度值都比晴天背景大气条件下的地面值要高,O3的浓度值则低于平均值,闪电频次与氮氧化物浓度存在正相关关系;(3)、LNOX从高空传输到地面也受风速风向的影响,风速与NOX浓度存在负相关关系,气流被偏北风控制的情况下,NOX的浓度值较低,气流在偏南风控制时,NOX则出现高浓度积累。     

灰色系统理论预测大气氮氧化物污染的应用

根据中国南方某省所辖城市近年来N0x污染指数的测量数据的统计资料，建立了GM(1，1）灰色预测模型，通过预测探讨了大气中氮氧化物指数的变化趋势。所建模型残差仅1．17％，关联系数为0．9067，精度较高，具有较好的可行性和适应性，可以为管理规则提供决策依据。     

1994-2006年长江三角洲和东北平原酸性气体浓度变化

 利用长江三角洲和东北平原地区大气本底站的二氧化硫（SO2）和氮氧化物（NOx）历史资料和近期取得的观测数据,探讨两个地区人为排放对这些气候相关酸性气体的不同贡献。从两种酸性气体过去和现在的浓度水平,估算了它们在两个地区的增长率,比较了NOx与SO2比值的不同变化趋势。结果表明,早在20世纪90年代中期,长江三角洲酸性气体污染水平已经较高,其后主要是NOx浓度显著升高,从而使该地区成为硫和氮污染并重的地区;东北平原酸性气体过去浓度很低,但这些气体以很高的速率增长,虽然目前浓度水平仍然比较低,但未来形势不容乐观。     

Impact of Aircraft NOx Emission on NOx and Ozone over China

A three-dimensional global chemistry transport model (OSLO CTM2) is used to investigate the impact of subsonic aircraft NOx emission on NOz and ozone over China in terms of a year 2000 scenario of subsonic aircraft NOx emission. The results show that subsonic aircraft NOx emission significantly affects northern China, which makes NOx at 250 hPa increase by about 50 pptv with the highest percentage of 60% in January, and leading to an ozone increase of 8 ppbv with 5% relative change in April. The NOx increase is mainly attributed to the transport process, but ozone increase is produced by the chemical process. The NOx increases by less than 10 pptv by virtue of subsonic aircraft NOx emission over China,and ozone changes less than 0.4 ppbv. When subsonic aircraft NOx emission over China is doubled, its influence is still relatively small.     

Impacts of Future NOx and CO Emissions on Regional Chemistry and Climate over Eastern China

A coupled chemical/dynamical model (SOCOL-SOlar Climate Ozone Links) is applied to study the impacts of future enhanced CO and NOx emissions over eastern China on regional chemistry and climate. The result shows that the increase of CO and NOx emissions has significant effects on regional chemistry, including NOx, CO, O₃, and OH concentrations. During winter, the CO concentration is uniformly increased in the northern hemisphere by about 10 ppbv. During summer, the increase of CO has a regional distribution. The change in O₃, concentrations near eastern China has both strong seasonal and spatial variations. During winter, the surface O₃, concentrations decrease by about 2 ppbv, while during summer they increase by about 2 ppbv in eastern China. The changes of CO, NOx, and O₃, induce important impacts on OH concentrations. The changes in chemistry, especially O₃, induce important effects on regional climate. The analysis suggests that during winter, the surface temperature decreases and air pressure increases in central-eastern China. The changes of temperature and pressure produce decreases in vertical velocity. We should mention that the model resolution is coarse, and the calculated concentrations are generally underestimated when they are compared to measured results. However, because this model is a coupled dynamical/chemical model, it can provide some useful insights regarding the climate impacts due to changes in air pollutant emissions.     

典型生态系统氮氧化物释放通量研究进展

氮氧化物(NOx)是全球氮循环的重要形式,也是影响全球气候和环境的重要污染气体。近年来随着人为源NOx排放量的逐渐下降,自然源NOx的释放通量及机制越来越受到人们的关注。本文综述了NOx的来源、气候和环境效应、释放通量估算方法和典型生态系统中自然源NOx释放通量特征及影响因素。然而,目前对不同生态系统NOx的研究还不够系统和深入,建立NOx标准测定方法和通量估算方法,对不同生态系统特别是海洋及湿地NOx的源汇格局,微生物的作用机制、人为氮输入的影响等开展系统地研究,才能准确评价不同生态系统对大气NOx的贡献及变化趋势,完善全球氮的收支平衡研究。     

煤炭从价征税实施在即

国务院办公厅近日印发《2014—2015年节能减排低碳发展行动方案》。根据方案,2014年到2015年,单位GDP能耗、化学需氧量、二氧化硫、氨氮、氮氧化物排放量将分别逐年下降3.9%、2%、2%、2%、5%以上,单位GDP二氧化碳排放量两年分别下降4%、3.5%以上。