Air Quality Modeling of Interpollutant Trading for Ozone Precursors in an Urban Area

Abstract

Emission trading is a market‐based approach designed to improve the efficiency and economic viability of emission control programs; emission trading has typically been confined to trades among single pollutants. Interpollutant trading (IPT), as described in this work, allows for trades among emissions of different compounds that affect the same air quality end point, in this work, ambient ozone (O₃) concentrations. Because emissions of different compounds impact air quality end points differently, weighting factors or trading ratios (tons of emissions of nitrogen oxides (NO_x) equivalent to a ton of emissions of volatile organic compounds [VOCs]) must be developed to allow for IPT. In this work, IPT indices based on reductions in O₃ concentrations and based on reductions in population exposures to O₃ were developed and evaluated using a three‐dimensional gridded photochemical model for Austin, TX, a city currently on the cusp of nonattainment with the National Ambient Air Quality Standards for O₃ concentrations averaged over 8 hr. Emissions of VOC and NO_x from area and mobile sources in Austin are larger than emissions from point sources. The analysis indicated that mobile and area sources exhibited similar impacts. Trading ratios based on maximum O₃ concentration or population exposure were similar. In contrast, the trading ratios did exhibit significant (more than a factor of two) day‐to‐day variability. Analysis of the air quality modeling indicated that the daily variability in trading ratios could be attributed to daily variations in both emissions and meteorology.     

Evidence for the Stepwise Behavioral Response Model (SBRM): the effects of Carbamate Pesticides on medaka (Oryzias latipes) in an online monitoring system

The Stepwise Behavioral Response Model (SBRM), which is a conceptual model, postulated that an organism displays a time-dependent sequence of compensatory Stepwise Behavioral Response (SBR) during exposure to pollutants above their respective thresholds of resistance. In order to prove the model, in this study, the behavioral responses (BRs) of medaka (Oryzias latipes) in the exposure of Arprocarb (A), Carbofuran (C) and Methomyl (M) were analyzed in an online monitoring system (OMS). The Self-Organizing Map (SOM) was utilized for patterning the obtained behavioral data in 0.1 TU (Toxic Unit), 1 TU, 2 TU, 5 TU, 10 TU and 20 TU treatments with control. Some differences among different Carbamate Pesticides (CPs) were observed in different concentrations and the profiles of behavior strength (BS) on SOM were variable depending upon levels of concentration. The time of the first significant decrease of BS (SD-BS) was in inverse ratio to the CP concentrations. Movement behavior showed by medaka mainly included No effect, Stimulation, Acclimation, Adjustment (Readjustment) and Toxic effect, which proved SBRM as a time-dependence model based on the time series BS data. Meanwhile, it was found that SBRM showed evident stress-dependence. Therefore, it was concluded that medaka SBR was both stress-dependent and time-dependent, which supported and developed SBRM, and data mining by SOM could be efficiently used to illustrate the behavioral processes and to monitor toxic chemicals in the environment.     

基于动态贝叶斯网络的石化装置火灾事故动态风险分析

为揭示石油炼化装置事故风险动态特性和事故情景演变路径,在对石化装置进行风险因素分析的基础上构建石化装置火灾事故故障树,基于贝叶斯网络非常规突发事故的演变过程,构建情景演变下的动态贝叶斯网络模型,在综合考虑应急措施的基础上,利用MATLAB软件和联合概率公式计算出各种事故场景的状态概率.以丙烯精馏装置火灾事故为例,结果表...     

核电厂凝结水精处理后置过滤器设置必要性分析

核电厂尤其是AP1000核电厂对二回路水质中的SO2-4控制非常严格,而精处理系统破碎树脂泄漏到二回路中高温分解是引起二回路SO2-4超标的一个重要原因。为了减少破碎树脂泄漏量,提出在精处理系统的混床后设置后置过滤器,并对后置过滤器设置的必要性进行了分析,为核电厂精处理系统的设计提供参考。     

Data quality evaluation and calibration of on-road remote sensing systems based on exhaust plumes

In recent years, with rapid increases in the number of vehicles in China, the contribution of vehicle exhaust emissions to air pollution has become increasingly prominent. To achieve the precise control of emissions, on-road remote sensing (RS) technology has been developed and applied for law enforcement and supervision. However, data quality is still an existing issue affecting the development and application of RS. In this study, the RS data from a cross-road RS system used at a single site (from 2012 to 2015) were collected, the data screening process was reviewed, the issues with data quality were summarized, a new method of data screening and calibration was proposed, and the effectiveness of the improved data quality control methods was finally evaluated. The results showed that this method reduces the skewness and kurtosis of the data distribution by up to nearly 67%, which restores the actual characteristics of exhaust diffusion and is conducive to the identification of actual clean and high-emission vehicles. The annual variability of emission factors of nitric oxide decreases by 60% – on average – eliminating the annual drift of fleet emissions and improving data reliability.     

Efficient nitrogen doped porous carbonaceous CO2 adsorbents based on lotus leaf

In this work, the waste biomass lotus leaf was converted into N-doped porous carbonaceous CO₂ adsorbents. The synthesis process includes carbonization of lotus leaf, melamine post-treatment and KOH activation. For the resultant sorbents, high nitrogen content can be contained due to the melamine modification and advanced porous structure were formed by KOH etching. These samples were carefully characterized by different techniques and their CO₂ adsorption properties were investigated in detail. These sorbents hold good CO₂ adsorption abilities, up to 3.87 and 5.89 mmol/g at 25 and 0°C under 1 bar, respectively. By thorough investigation, the combined interplay of N content and narrow microporous volume was found to be responsible for the CO₂ uptake for this series of sorbents. Together with the high CO₂ adsorption abilities, these carbons also display excellent reversibility, high CO₂/N₂ selectivity, applicable heat of adsorption, fast CO₂ adsorption kinetics and good dynamic CO₂ adsorption capacity. This study reveals a universal method of obtaining N-doped porous carbonaceous sorbents from leaves. The low cost of raw materials accompanied by easy synthesis procedure disclose the enormous potential of leaves-based carbons in CO₂ capture as well as many other applications.     

微宇宙系统中氯苯的生物强化处理

将分离出的一株降解氯苯的高效土著菌Acinetobacter calcoaceticus和自然材料组成微宇宙系统,通过改变系统组成、重金属和营养物添加水平、悬浮物浓度以及温度,研究了系统中氯苯的去除机制.结果表明,微宇宙系统中氯苯的去除主要是加入菌株的降解作用;加入降解菌后,8d内系统中氯苯的去除率可达到98.3%.底泥和光照对微宇宙系统中氯苯的去除具有明显的促进作用(p0.05).悬浮物在实验前期对氯苯的去除产生明显的促进作用.微宇宙系统中氯苯的去除率随着温度的升高而增加,30.0℃条件下培养7d后,氯苯的去除率可达95.4%;10.0℃和15.0℃下培养14d后,氯苯的去除率分别为43.4%和68.5%.营养盐加入比例达1.0%时,可明显促进氯苯的去除.Cd2+和Hg2+浓度达到10.0mg·L-1时,可对系统中氯苯的去除率产生显著(p0.05、p0.01)降低作用.研究结果可为突发性事故造成的氯苯污染水体的微生物修复提供基本的理论和实践依据.     

太湖不同湖区蓝藻细胞裂解速率的空间差异

2009年在太湖蓝藻水华形成初期(五月)、盛发期(九月)和衰亡期(十月和十一月),运用基于颗粒态酯酶,溶解性酯酶以及酯酶衰变常数测定的酯酶活性方法对不同湖区(藻型和草型湖区)蓝藻的细胞裂解速率进行了计算,在测定颗粒态酯酶、溶解性酯酶活性时,同步分析了太湖优势种群中蓝藻叶绿素a的含量.统计分析结果表明,叶绿素a的浓度与颗粒态酯酶、溶解性酯酶活性有很好的相关性,说明以酯酶活性为指标来计算太湖蓝藻细胞裂解速率是可行的.对不同湖区的细胞裂解速率进行比较,可见湖心和西太湖在蓝藻水华形成初期细胞裂解速率分别为0.072,0.048d-1.水华盛发期以及水华衰亡期,湖心和西太湖的细胞裂解速率分别为0.074～0.770d-1,0.014～0.110d-1.太湖湖心磷酸盐浓度比西太湖低,所以蓝藻生长速率慢,导致细胞裂解速率比西太湖高.但是,在梅梁湾和贡湖,衰亡末期磷酸盐浓度比其它月份高,细胞裂解速率也高.4个采样点在衰亡末期的细胞裂解速率比水华形成初期,暴发期和衰亡初期要高,可能的原因是气温和水体温度下降导致蓝藻生长速度减慢.本研究结果表明,太湖蓝藻细胞裂解速率有明显的空间差异,其具体的影响因素很多,营养盐只是其中一个.     

Formation of secondary inorganic aerosol in a frigid urban atmosphere

•Harbin showed relatively high threshold RH (80%) for apparent increase of SOR. •The observed SOR were at the lower end of the ratios from Beijing’s winter. •Temperature-dependent increase of NOR was sharper than that of SOR. • NOR increased with stronger biomass burning impact but SOR was largely unchanged. Formation of secondary inorganic aerosol (SIA) was investigated during a six-month long heating season in Harbin, China. Enhanced sulfate formation was observed at high relative humidity (RH), with the same threshold RH (80%) for both colder and warmer measurement periods. Compared to wintertime results from Beijing, the threshold RH was considerably higher in Harbin, whereas the RH-dependent enhancement of sulfur oxidation ratio (SOR) was less significant. In addition, the high RH events were rarely encountered, and for other periods, the SOR were typically as low as ~0.1. Therefore, the sulfate formation was considered inefficient in this study. After excluding the several cases with high RH, both SOR and the nitrogen oxidation ratio (NOR) exhibited increasing trends as the temperature increased, with the increase of NOR being sharper. The nitrate to sulfate ratio tended to increase with increasing temperature as well. Based on a semi-quantitative approach, this trend was attributed primarily to the temperature-dependent variations of precursors including SO₂ and NO₂. The influence of biomass burning emissions on SIA formation was also evident. With stronger impact of biomass burning, an enhancement in NOR was observed whereas SOR was largely unchanged. The different patterns were identified as the dominant driver of the larger nitrate to sulfate ratios measured at higher concentrations of fine particulate matter.     

长江感潮河段有机碳的潮汐和季节变化规律

以长江感潮河段─南通段为研究对象,于2019年逐月采集涨潮和落潮期间分层水体样品. 测定了颗粒有机碳（particulate organic carbon, POC）和溶解有机碳（dissolved organic carbon, DOC）浓度,并同步进行了不同营养盐添加的室内模拟实验,测定了生物可降解溶解有机碳（biodegradable DOC, BDOC）的浓度. 研究结果表明,底层POC浓度最高,中层POC浓度最低. POC浓度与潮高呈显著负相关,与水温没有显著相关性. 表层、中层和底层DOC浓度没有显著差异,DOC浓度均值为（7.55 ± 1.50） mg·L^-1. 涨潮和落潮DOC浓度没有显著差异,DOC浓度与水温呈显著正相关. BDOC在DOC中的占比为40.88% ± 13.91%,不同营养盐添加处理的BDOC在DOC中的占比没有显著差异. BDOC浓度和潮高呈显著正相关. 这些研究结果表明,与POC 不同, DOC和BDOC具有显著季节变化规律. 长江下游潮汐作用对有机碳的分布具有重要影响,涨潮对POC产生稀释作用,但促进了DOC生物可降解性的升高.