Potential of secondary aerosol formation from Chinese gasoline engine exhaust

Light-duty gasoline vehicles have drawn public attention in China due to their significant primary emissions of particulate matter and volatile organic compounds(VOCs). However,little information on secondary aerosol formation from exhaust for Chinese vehicles and fuel conditions is available. In this study, chamber experiments were conducted to quantify the potential of secondary aerosol formation from the exhaust of a port fuel injection gasoline engine. The engine and fuel used are common in the Chinese market, and the fuel satisfies the China V gasoline fuel standard. Substantial secondary aerosol formation was observed during a 4–5 hr simulation, which was estimated to represent more than 10 days of equivalent atmospheric photo-oxidation in Beijing. As a consequence, the extreme case secondary organic aerosol(SOA) production was 426 ± 85 mg/kg-fuel, with high levels of precursors and OH exposure. The low hygroscopicity of the aerosols formed inside the chamber suggests that SOA was the dominant chemical composition. Fourteen percent of SOA measured in the chamber experiments could be explained through the oxidation of speciated single-ring aromatics. Unspeciated precursors, such as intermediate-volatility organic compounds and semi-volatile organic compounds, might be significant for SOA formation from gasoline VOCs. We concluded that reductions of emissions of aerosol precursor gases from vehicles are essential to mediate pollution in China.     

From proposal to decision: Suggestions for tightening up the “NEPA process”

Although the process of documenting compliance with NEPA (the National Environmental Policy Act) requires no drastic revisions, it can be managed more rigorously. Suggestions for revision can be grouped under five major steps: 1) getting a complete proposal from the applicant; 2) getting the decision-making process onto the right decision-making path; 3) modifying the applicant's proposal 4) going down a shorter path through the EA/FONSI (environmental assessment and finding of no significant impact) or through categorical exclusion review; and 5) going down the longer path through the EIS. Step 2 is perhaps the most critical, because there a decision must be made whether to write an EA/FONSI or an EIS, on the basis of whether the proposal would “significantly affect … the … environment.” In the past, this decision has not always been made promptly or rigorously. Accordingly, we suggest that the agency responsible for NEPA compliance should develop a system (a “black box”), consisting of a core group of specialists working with an interdisciplinary team, using sophisticated techniques for modeling impacts and directing both their research and their writing according to the concept of significance. By determining more efficiently and reliably whether the impacts of a proposal would be significant, such an approach would improve management of the total process.     

流动注射法测定水中总碳酸盐

将流动注射应用于水中总碳酸盐的分析,并研究了各种实验条件对于结果的影响。实验证明,这种方法基本不存在干扰,在采样量为0.05ml时,检出限(3σ)为80mg/L;峰高的检测范围100~1000mg/L;峰宽的检测范围1000~5000mg/L,能够很好地应用于火力发电厂中生水、锅炉水的总碳酸盐测定。     

高压密封消解-流动注射同时测定海水中总氮和总磷

建立了高压密封消解-流动注射同时测定海水中总氮和总磷的方法,方法采用特制聚四氟乙烯密封消解罐,经高压消解锅消解后,用流动注射分析仪同时测定海水中的总氮和总磷。结果显示,总氮和总磷在0~3.20 mg/L范围内线性良好,总氮相关系数(r)=0.9997,检出限为0.012 mg/L,相对标准偏差为0.65%~2.59%,加标回收率为97.8%~102%;总磷相关系数(r)=0.9999,检出限为0.006 mg/L,相对标准偏差为0.50%~6.67%,加标回收率为98.8%~101%。该方法可同时测定海水中总氮和总磷,方法准确度和精密度良好,满足分析要求,适用于大批量海水样品中总氮和总磷的快速准确定量。     

微波联合消解流动注射光度法测定水中总氮和总磷

利用微波联合消解水样,采用流动注射分析技术,建立了在线测定水中总氮和总磷的快速分析方法.优化了试验条件,在线性范围内,总氮和总磷的工作曲线线性关系良好,检出限分别为0.03 mg/L和0.01 mg/L,相对标准偏差分别为1.5%和1.2%,加标回收率分别为96.7%～103%和98.8%～102%.     

流动注射-氢化物发生-原子荧光光谱法测定土壤中铅

采用流动注射-氢化物发生-原子荧光光谱法测定土壤中的铅,工作曲线线性关系良好,检出限为0.25 mg/kg,相对标准偏差＜3.5%,加标回收率为93.0%～105%.该方法简便快速,测定结果准确可靠.     

流动注射在线氢化物发生—原子荧光光谱法测定环境水样中痕量无机汞和有机汞

提出了一种流动注射在线氢化物发生—原子荧光光谱法测定水样中痕量无机汞和有机汞的分析方法。以溴化剂作为有机汞的消解剂 ,在有、无溴化剂的存在下 ,采用流动注射在线氢化物发生—原子荧光光谱法分别测定总汞和无机汞 ,差减法求出有机汞的含量。方法操作简便快速 ,灵敏度高 ,干扰少 ,经加标回收实验验证 ,回收率达 95 %～ 10 5 %。     

模拟在役井注减氧空气对1Cr-L80井筒管材防腐研究

目的在充分调研陆上及渤海周边相似油气田注气开发井筒腐蚀情况的基础上,明确注减氧空气开发井对井筒全寿命周期管材腐蚀速率大小。方法系统性开展注气井不同含氧量条件下的动态腐蚀实验研究,并对生产井动态腐蚀进行评价,深入分析减氧空气对油井管腐蚀行为,分类分层次分析归纳注减氧空气工况管柱腐蚀特性、腐蚀速率影响因素以及管柱腐蚀风险。结果得出在注气井井口、井中、井底工况,不同氧气浓度下,1Cr-L80管材在注气井井口、井中、井底的腐蚀关系曲线。在含氧量为5%(质量分数)的注气井井口、井中、井底,1Cr-L80的腐蚀速度分别为0.345、0.2147、0.1158mm/a;在含氧量为21%的注气井井口、井中、井底,1Cr-L80的腐蚀速率分别为0.7399、1.2854、2.4506 mm/a。结论1Cr-L80材质腐蚀速率均保持在较高水平,老井直接注入空气会存在高腐蚀风险。     

直接法测定大气中的非甲烷烃

介绍了在２个监测点，用直接法测定大气中的非甲烷烃。测定方法的检出限可达０．００６５ｍｇ／ｍ＾３，在线性范围０－１０ｍｇ／ｍ＾３时，线性相关系数为０．９９９５，相对标准焦虑差为２．８％。结果表明，由于大气逆温层、工业排放源、汽车排气对非甲烷烃的浓度变化产生影响，其日变化曲线呈双峰形。     

在线树脂富集流动注射法测定水中痕量酚

研究了用流动注射分析中的流体动力学注入技术与在线树脂富集相结合的方式，富集水中痕量苯酚，以４－氨基安替比林比色法测定的方法。结果表明，当进样频率为２４个样品每小时时，方法的检出限为０．０５ｍｇ／Ｌ，线性范围为０．０５～７ｍｇ／Ｌ；对水中苯酚重复测定１０次，相对标准偏差小于２％；回收率为９９％～１０５％。