Formaldehyde concentration and its influencing factors in residential homes after decoration at Hangzhou, China

Air pollution surveys of formaldehyde(HCHO) were conducted in 2324 rooms decorated within one year in 2007-2009 in Hangzhou,China.The mean HCHO concentration(C HCHO) was 0.107 ± 0.095 mg/m 3,and 38.9% of samples exceeded the Chinese National Standard GB 50325-2010.Over the past 3 years,the C HCHO decreased with time(p < 0.05).Relationships of potential factors to indoor C HCHO were also evaluated.C HCHO was related to temperature(T),relative humidity(RH),time duration of the windows and doors being closed before sampling(DC),time duration from the end of decoration to sampling(DR) and source characteristics(d).A model to relate indoor C HCHO to these five factors(T,RH,DC,DR,d) was established based on 298 samples(R 2 = 0.87).Various factors contributed to C HCHO in the following order:T,43.7%;d,31.0%;DC,10.2%;DR,8.0%;RH,7.0%;specifically,meteorological conditions(i.e.,RH plus T) accounted for 50.7%.The coefficient of T and RH,R TH,was proposed to describe their combined influence on HCHO emission,which also had a linear relationship(R 2 = 0.9387) with HCHO release in a simulation chamber test.In addition,experiments confirm that it is a synergistic action as T and RH accelerate the release of HCHO,and that is a significant factor influencing indoor HCHO pollution.These achievements could lead to reference values of measures for the efficient reduction of indoor HCHO pollution.     

2006~2009年我国超大城市霾天气特征及影响因子分析

收集了2006～2009年北京、上海、广州和成都能见度等气象因子以及SO2、NO2和PM10等环境空气质量资料,在此基础上统计分析上述4个超大城市霾天气频率季节和年际变化特征及其主要的影响因子.结果表明,北京、上海、广州和成都霾天气频率季节最高值分别为夏季、冬季、春季和秋季.北京和广州霾天气频率呈现逐渐下降趋势,而上海和成都呈现逐渐上升趋势.PM10和相对湿度是影响能见度或霾天气频率关键因子.北京能见度变化对相对湿度比较敏感,而上海和广州对PM10浓度变化比较敏感,成都对相对湿度和PM10浓度敏感程度相当.     

测定废水中总磷的两种预处理方法的比较

对测定总磷含量的两种预处理方法即过硫酸钾和硝酸-硫酸消解方法进行了对比实验。这两种方法均为国家环保部认可的标准方法,经实验证明其精密度和准确度都符合要求。     

黄土高原人工林土壤水分效应的地带性特征

为提高黄土高原人工植被建设成效,依据天然植被呈地带性分布的规律,对比分析不同地带人工林与天然植被对土壤水分利用的差异。结果表明:不同植被地带的人工林下均存在一定程度的水分亏缺和干化层现象,其严重程度为森林带<森林草原带<典型草原带。森林带的水分条件可满足林木成材对水分的需求,林木采伐后土壤水分可得到很好恢复;森林草原带可满足10龄以下林木生长对水分需求,10龄以上林分的水分亏缺严重,林木采伐后土壤水分恢复进程缓慢;典型草原带不能满足人工林生长对水分需求。在此基础上,提出了与地带性水分条件相适应的人工林草植被建设模式。     

Spatial distribution of soil heavy metal pollution estimated by different interpolation methods: accuracy and uncertainty analysis

Mapping the spatial distribution of contaminants in soils is the basis of pollution evaluation and risk control. Interpolation methods are extensively applied in the mapping processes to estimate the heavy metal concentrations at unsampled sites. The performances of interpolation methods (inverse distance weighting, local polynomial, ordinary kriging and radial basis functions) were assessed and compared using the root mean square error for cross validation. The results indicated that all interpolation methods provided a high prediction accuracy of the mean concentration of soil heavy metals. However, the classic method based on percentages of polluted samples, gave a pollution area 23.54-41.92% larger than that estimated by interpolation methods. The difference in contaminated area estimation among the four methods reached 6.14%. According to the interpolation results, the spatial uncertainty of polluted areas was mainly located in three types of region: (a) the local maxima concentration region surrounded by low concentration (clean) sites, (b) the local minima concentration region surrounded with highly polluted samples; and (c) the boundaries of the contaminated areas.     

蓄滞洪区洪水资源利用的风险效益分析

利用蓄滞洪区的现有洼淀拦蓄洪水,实现其洪水资源化是合理开发和有效利用水资源的重要途径。以天津市大黄堡洼蓄滞洪区为例,建立了蓄滞洪区洪灾风险的评价指标体系,提出了相对风险度的概念及其计算方法,并分析计算了大黄堡洼7种洪水资源利用情景下的综合风险度、相对风险度、损失、经济效益和生态效益。结果表明:与综合风险度相比,相对风险度更为直观形象,便于决策者判断,据其能更及时地做出应对策略,了解损失、效益值受蓄水量和淹没范围的共同影响。最后综合分析风险、损失、效益计算结果,优选出合理的洪水资源利用情景,并分析了其合理性。     

饱和南京细砂孔压增量模型的普适性研究

循环荷载作用下饱和砂土的孔压增长规律是土动力学的核心内容之一。基于笔者在给定相对密度、均等固结条件下饱和南京细砂的不排水等幅循环三轴试验结果建立的孔压增量模型,进一步进行了不同相对密度、不同固结比务件下饱和南京细砂的不排水等幅循环三轴试验,将上述均等固结的孔压增量模型拓展为适用于不同相对密度、均等和非均等固结条件的孔压增量模型。采用拓展后的孔压增量模型对试验结果进行分析的结果表明:通过该孔压增量模型预测验证试验的孔压与验证试验测试的孔压具有较好的一致性,说明该孔压增量模型具有普适性。     

好氧颗粒污泥系统中溶解性微生物代谢产物的特征及主要组分

采用SBR反应器以絮状活性污泥为接种污泥培养好氧颗粒污泥,主要考察好氧颗粒污泥系统中溶解性微生物代谢产物(SMP)的产生、相对分子质量分布以及主要组成物质.结果表明SMP是出水COD的主要组分,浓度为71~85 mg·L-1,SMP的产生与微生物对基质的利用、微生物衰亡和胞外聚合物(EPS)的水解有关.相对分子质量分布表明大部分SMP相对分子质量小于3×103,所占比例为54.8%~71.7%,而相对分子质量大于100×103的组分只占总SMP的一小部分,所占比例为9.3%~14.5%.三维荧光光谱分析表明,出水SMP具有4个峰,分别属于类芳香蛋白质、类色氨酸蛋白质、类腐殖酸物质和类富里酸物质.气质联用(GC-MS)分析表明SMP主要成分为酯类、短链烷烃、烯烃和醇类,所占质量分数分别为39.0%、14.9%、11.7%和7.6%.其中邻苯二甲酸二酯是出水SMP中主要组成物质,所占质量分数为32.0%.     

水培试验下水稻Pb吸收累积关键生育期

水稻不同生育期对Pb的吸收累积差异明显.本研究通过水培试验,分别在水稻不同生育期(分蘖期、拔节期、孕穗期、灌浆期、蜡熟期和成熟期)和全生育期添加0.5 mg·L~(-1)的外源Pb,以全生育期不添加外源Pb作为对照,研究水稻不同生育期Pb吸收累积的影响,明确水稻吸收累积Pb的关键生育时期及对水稻植株和糙米Pb累积的贡献.结果表明:①单一生育期Pb胁迫处理时,水稻株高和分蘖数差异不明显,而全生育期Pb胁迫处理下水稻株高和生物量均受到明显抑制;②水稻成熟后不同部位的Pb含量差异表现为:根系茎节1其他茎节根基茎茎叶穗轴谷壳糙米;不同生育期处理下糙米Pb含量范围为0.1～1.2 mg·kg~(-1),其顺序为:孕穗期Pb胁迫拔节期Pb胁迫分蘖期Pb胁迫灌浆期Pb胁迫成熟期Pb胁迫蜡熟期Pb胁迫;③水稻植株Pb累积量相对贡献率在水稻生殖生长时期(灌浆期、蜡熟期和成熟期)较大,而水稻地上部位Pb累积量相对贡献率在水稻营养生长时期(分蘖期、拔节期和孕穗期)较大;④孕穗期是糙米Pb积累的关键生育期,对糙米Pb累积的相对贡献率为43.3%,其次是拔节期和分蘖期处理,相对贡献率分别为24.4%和21.3%;⑤建议在水稻孕穗期适度采用淹水灌溉、施加改良剂或叶面阻控等技术措施,以降低糙米Pb累积,实现Pb污染稻田安全利用.     

济南市城区夏季臭氧污染过程及来源分析

2019年夏季,在济南市城区开展了大气臭氧(O3)及其前体物[挥发性有机物(VOCs)和氮氧化物(NOx)]的综合观测研究,观测发现,日最大8h φ(O3)均值为(103.0±14.5) ×10-9,φ(NOx)平均值为(16.7±11.3) ×10-9,VOCs的体积分数和活性水平分别为(22.4±9.4)×10-9...