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A modeling framework to assess fenceline monitoring and self-reported upset emissions of benzene from multiple oil refineries in Texas 评估得克萨斯州多家炼油厂苯的围栏监测和自报扰动排放的建模框架
IF 3.8 Q2 ENVIRONMENTAL SCIENCES Pub Date : 2024-08-01 DOI: 10.1016/j.aeaoa.2024.100281

Benzene as one type of hazardous air pollutants (HAPs) is produced by industrial production processes and/or emitted during upset events caused by man-made or natural accidents. Although upset emissions of benzene can be a significant contributor to the total emission, it is still challenging to quantify. This study first develops a fast modeling framework using obstacle-resolving computational fluid dynamics modeling to compare the modeled within-facility-scale passive pollutant dispersion with the observed levels based on self-reported emissions for fourteen facilities in Texas, United States. Results of numerical simulations demonstrate that neglecting the obstacle effect can underpredict (overpredict) the near-(far-)field concentrations for a low source. For a source located above obstacles, underprediction occurs at all distances. The diagnostic framework is applied to 107 self-reported upset emission events for fourteen petroleum refineries in Texas from year 2019–2022. Considering different metrics across all events, it can be concluded that the modeled concentrations based on self-reported emissions likely underpredict the observed concentration increments. Depending on the possible source height, the median factor of underprediction ranges from 3 to 95 based on the average-plume metric. The agreement between model and observation is better for events characterized by high emission amounts and rates, which also correspond to high observed concentration increments. Overall, the research highlights the importance of considering obstacles and demonstrates the potential application of the current approach as an efficient diagnostic method for self-reported upset emissions using fenceline observations of HAPs.

苯是有害空气污染物(HAPs)的一种,由工业生产过程产生和/或在人为或自然事故造成的扰动事件中排放。尽管苯的扰动排放在总排放量中占很大比例,但对其进行量化仍然具有挑战性。本研究首先利用障碍物解析计算流体动力学建模技术开发了一个快速建模框架,将建模的设施范围内被动污染物扩散与根据美国得克萨斯州 14 家设施的自我报告排放量观测到的水平进行比较。数值模拟结果表明,忽略障碍物效应会低估(高估)低排放源的近场(远场)浓度。对于位于障碍物上方的污染源,在所有距离上都会出现预测不足的情况。诊断框架适用于德克萨斯州 14 家炼油厂在 2019-2022 年发生的 107 起自报扰动排放事件。考虑到所有事件的不同指标,可以得出结论:基于自报告排放的模型浓度很可能无法预测观测到的浓度增量。根据可能的污染源高度,基于平均烟羽指标,预测不足的中位系数从 3 到 95 不等。对于高排放量和高排放率的事件,模型和观测之间的一致性更好,这也与观测到的高浓度增量相对应。总之,该研究强调了考虑障碍物的重要性,并证明了当前方法作为一种利用 HAPs 边线观测数据对自报的扰动排放进行有效诊断的方法的潜在应用价值。
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引用次数: 0
Status of near-road air quality monitoring stations and data application 近路空气质量监测站和数据应用现状
IF 3.8 Q2 ENVIRONMENTAL SCIENCES Pub Date : 2024-08-01 DOI: 10.1016/j.aeaoa.2024.100292

In order to evaluate the impact of traffic emissions on urban air quality, an increasing number of cities have established near-road air quality monitoring stations (hereafter referred to as roadside stations). This study reviews the system of roadside stations, the data application, and the evolution of air pollutant concentrations in the traffic environment in typical cities, and proposes optimization suggestions roadside stations in the future. The results show a steady increase in publications on roadside stations over the years, with the annual average number of publications after 2020 being approximately 10 times the annual mean during 1994–2001. The literature mainly focused on ‘air pollution’, ‘particulate matter’, ‘emission’, etc., highlighting the impact of traffic emissions on urban air quality and human health. The purpose and principles of setting up roadside stations vary from country to country, but they are mainly used to assess the impact of vehicle emissions on air quality and to protect human health in the vicinity of roads. Over the past decade, near-road NO2 concentrations in typical cities have decreased by 30%–50%, although they remain higher than those observed in the urban atmosphere. The comprehensive analysis based on long-term data from roadside stations can provide insight into the effectiveness of vehicle emission control measures, and serve as a scientific basis for the formulation of future public health protection policies.

为了评估交通排放对城市空气质量的影响,越来越多的城市建立了近路空气质量监测站(以下简称路边站)。本研究回顾了路边站系统、数据应用以及典型城市交通环境中空气污染物浓度的变化情况,并对未来路边站的优化提出了建议。研究结果表明,近年来有关路边站的文献数量稳步增长,2020 年以后的年均文献数量约为 1994-2001 年期间的 10 倍。文献主要集中在 "空气污染"、"颗粒物"、"排放 "等方面,突出了交通排放对城市空气质量和人类健康的影响。各国建立路边监测站的目的和原则不尽相同,但主要用于评估汽车尾气排放对空气质量的影响,保护道路附近的人类健康。在过去十年中,典型城市的近路二氧化氮浓度下降了 30%-50%,但仍高于城市大气中观测到的浓度。根据路边监测站的长期数据进行综合分析,可以深入了解车辆排放控制措施的有效性,为制定未来的公共健康保护政策提供科学依据。
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引用次数: 0
Potential of user training for reducing emissions of firewood stoves 用户培训在减少柴灶排放方面的潜力
IF 3.8 Q2 ENVIRONMENTAL SCIENCES Pub Date : 2024-08-01 DOI: 10.1016/j.aeaoa.2024.100287

Emissions from wood-burning stoves contribute to local air pollution. However, it is difficult to determine the real emissions from such stoves, especially due to unknown user behaviour, which can have a large impact on emissions. In this study, the low-cost emission reduction measure “user training” was evaluated to determine its emission reduction potential on firewood stoves. Two sets of tests were carried out. First, a field measurement campaign was conducted in Styria (Austria) with four wood stoves, where gaseous and particulate emissions were measured before and after a user training on optimised heating behaviour (e.g. ignition mode, fuel properties and placement in the combustion chamber, air supply). Gaseous emissions (carbon monoxide – CO, organic gaseous compounds – OGC) were measured continuously, while particulates were measured in batches, in undiluted and hot as well as in diluted and cooled flue gas in parallel with a specific field measurement setup. In addition, particle filters were analysed to quantify the concentration of the carcinogenic compound benzo(a)pyrene (BaP). Second, user training workshops were conducted. These tests had a simple measurement setup in order to increase the number of tests. Thus, only CO emissions were evaluated.

The results show that real life emissions in the field are high and have a high variability compared to laboratory tests and official type test results. However, user training showed a significant reduction of CO, OGC, TSP and BaP emissions of 42%, 57%, 45% and 76% (median), respectively. In addition, TSPsum (sum of hot and cooled particle emission samples) emissions decreased by 39% (median) after user training. The relative reduction rates of all batches show that the highest emission reduction potential was identified for BaP, with a reduction rate of up to 97%. The results of the workshop tests confirmed the high variability in user behavior and the range for the emission reduction potentials, with a median CO reduction of 41%.

The emission reduction potential of the user training measure is comparable to state-of-the-art technological measures such as electrostatic precipitators and catalysts. However, these measures are costly and require a high level of technical sophistication. User training, on the other hand, is relatively cheap, easy to implement and suitable for all users. Of course, there is some risk that trained end-users will revert to their old habits, leading to higher emissions again. Therefore, regular training may be necessary to maintain the higher level of performance. As we did not assess this aspect in our work, further research would be needed to prove this theory.

焚烧木材的炉灶产生的废气造成了当地的空气污染。然而,很难确定此类炉灶的实际排放量,特别是由于未知的用户行为会对排放量产生很大影响。在这项研究中,对低成本减排措施 "用户培训 "进行了评估,以确定其对柴火炉灶的减排潜力。共进行了两组测试。首先,在施蒂里亚州(奥地利)对四台柴炉进行了实地测量,在对用户进行优化加热行为(如点火模式、燃料特性和燃烧室位置、空气供应)培训前后,对气体和颗粒物排放进行了测量。气体排放(一氧化碳 - CO、有机气体化合物 - OGC)是连续测量的,而颗粒物则是分批测量的,在未稀释的热烟气中,以及在稀释和冷却的烟气中,同时使用特定的现场测量装置进行测量。此外,还对颗粒过滤器进行了分析,以量化致癌化合物苯并(a)芘(BaP)的浓度。其次,举办了用户培训讲习班。为了增加测试次数,这些测试采用了简单的测量设置。结果表明,与实验室测试和官方型式测试结果相比,实际生活中的现场排放量很高,而且变异性很大。然而,用户培训显示,CO、OGC、TSP 和 BaP 排放量分别显著减少了 42%、57%、45% 和 76%(中位数)。此外,经过用户培训后,TSPsum(热和冷颗粒排放样本的总和)排放量减少了 39%(中位数)。所有批次的相对减排率显示,BaP 的减排潜力最大,减排率高达 97%。车间测试的结果证实了用户行为的高度可变性和减排潜力的范围,CO 减排量的中位数为 41%。然而,这些措施成本高昂,对技术复杂程度要求很高。而用户培训则相对便宜,易于实施,适合所有用户。当然,经过培训的最终用户可能会重拾旧习,导致排放量再次增加。因此,可能需要定期培训,以保持较高的性能水平。由于我们在工作中没有对这方面进行评估,因此需要进一步的研究来证明这一理论。
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引用次数: 0
Aircraft-derived CH4 emissions from surface and in-situ mining activities in the Alberta oil sands region 阿尔伯塔油砂地区地表和原地采矿活动中飞机产生的甲烷排放量
IF 3.8 Q2 ENVIRONMENTAL SCIENCES Pub Date : 2024-08-01 DOI: 10.1016/j.aeaoa.2024.100280

The identification and reduction of methane sources is considered an important part of the fight to stem greenhouse gas (GHG) emissions to the atmosphere. One of the largest industrial contributors to national GHG emissions in Canada is the Alberta Oil Sands Region. To quantify and investigate the spatial distribution and temporal variability of methane emissions from this region, airborne measurements were conducted in 2017 and 2018 with three aircraft. 59 flights were conducted in total to assess emissions for both open-pit and in-situ facilities, in both cold and warm seasons. Derived emission rates were higher than those reported in national inventories by 30%–96% depending on the facility. In-situ facilities had emission rates an order of magnitude lower than surface mining operations and differed significantly from inventory estimates. No statistical differences in CH4 emissions between cold and warm seasons were observed, substantiating the use of simple upscaling to annual emissions within inventories. Rather than confirming a reported decrease in emissions between 2013 and 2018, the measurements suggest essentially no change from the 18 t h−1 for the region observed in 2013. Overall, the results suggest that current methods of CH4 emission determination within the oil sands region, for use in reporting, require improvement.

识别和减少甲烷来源被认为是遏制温室气体(GHG)向大气排放斗争的重要组成部分。阿尔伯塔油砂地区是加拿大全国温室气体排放的最大工业贡献者之一。为了量化和研究该地区甲烷排放的空间分布和时间变化,2017 年和 2018 年使用三架飞机进行了空中测量。共进行了 59 次飞行,以评估露天和原地设施在寒冷和温暖季节的排放情况。推算出的排放率比国家清单中报告的排放率高 30%-96%,具体取决于设施。原地设施的排放率比露天采矿作业低一个数量级,与清单估计值相差很大。冷季和暖季的甲烷排放量在统计上没有差异,这证明了在清单中使用简单的年排放量放大法是正确的。测量结果表明,2013 年至 2018 年期间该地区的排放量与 2013 年观测到的 18 吨/小时-1 相比基本没有变化,而不是证实了所报告的排放量减少。总体而言,结果表明,油砂地区目前用于报告的甲烷排放量测定方法需要改进。
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引用次数: 0
The impact of shipping on the air quality in European port cities with a detailed analysis for Rotterdam 航运对欧洲港口城市空气质量的影响及对鹿特丹的详细分析
IF 3.8 Q2 ENVIRONMENTAL SCIENCES Pub Date : 2024-08-01 DOI: 10.1016/j.aeaoa.2024.100278

Air quality in cities with large maritime ports is considerably impacted by emissions from shipping activity which is of a growing relevance due to an increasing relative contribution. To explore the extent of shipping emissions to ambient air quality, simulations with the chemical transport model LOTOS-EUROS (LOng Term Ozone Simulation – EURopean Operational Smog model) were performed for the year 2018 at an approximate 1 × 1 km resolution for six European cities with large ports, i.e., Rotterdam, Antwerp, Hamburg, Amsterdam, Le Havre, and London. It was found that depending on the investigated city, 6.5%–62% of the nitrogen dioxide (NO2) concentration in the city centres is attributable to shipping activities. This corresponds to contributions of 1.8–11.5 μg/m3 to the ambient air NO2 concentrations. The average NO2 contribution of shipping in these six cities was 28% (7.1 μg/m3). The largest relative contribution was found for Le Havre where 62% (10.8 μg/m3) of the annual average NO2 concentration was caused by shipping emissions. The largest absolute contribution is found for the city centre of Hamburg with 11.5 μg/m3 (41%). The lowest absolute and relative contribution (respectively 1.8 μg/m3 and 6.5%) are found for London, also having the smallest port in terms of tonnage throughput, which is one of the influential factors that determine emission totals, investigated in this study. For the other investigated pollutants, i.e., PM2.5, PM10 and SO2, contributions from shipping were less pronounced with average contribution for all cities of 10% (1.2 μg/m3) 7% (1.5 μg/m3) and 4% (0.16 μg/m3) respectively. To assess the effect of model choices on these results, this study also looked into the choice of simulation resolution and relations between meteorological parameters and NO2 concentrations. Following simulations with varying chemical transport model resolutions (1 × 1 km to 24 × 24 km), it is found that a decrease in ambient air pollutant concentrations away from localized emission sources is more pronounced at higher (1 × 1 km) model resolutions and source contributions are influenced more significantly than total concentrations. Considering meteorology, generally low wind speeds (1–2 m/s) lead to high NO2 concentration in city centres. For the cities where the port is much closer to the city centre (e.g., London, Le Havre, Hamburg and Antwerp) the absolute NO2 concentrations as well as the contributions from shipping emissions become highest for windless conditions. The high concentrations (>60 μg/m3 NO2) only occur when wind speeds fall below 6 m/s.

拥有大型海港的城市的空气质量深受航运活动排放物的影响,而航运活动排放物的相对影响越来越大。为了探究航运排放对环境空气质量的影响程度,我们使用化学传输模型 LOTOS-EUROS(LOng Term Ozone Simulation - EURopean Operational Smog model)对欧洲六个大型港口城市(即鹿特丹、安特卫普、汉堡、阿姆斯特丹、勒阿弗尔和伦敦)的 2018 年空气质量进行了模拟,分辨率约为 1 × 1 km。研究发现,根据调查城市的不同,市中心 6.5%-62% 的二氧化氮(NO2)浓度可归因于航运活动。这相当于 1.8-11.5 μg/m3 的环境空气二氧化氮浓度。在这六个城市中,航运对二氧化氮的平均贡献率为 28%(7.1 μg/m3)。相对贡献最大的城市是勒阿弗尔,其二氧化氮年平均浓度的 62% (10.8 μg/m3)是由航运排放造成的。绝对贡献最大的是汉堡市中心,为 11.5 μg/m3(41%)。伦敦的绝对值和相对值最小(分别为 1.8 μg/m3 和 6.5%),同时也是吞吐量最小的港口。对于其他调查的污染物,即 PM2.5、PM10 和二氧化硫,航运的贡献不太明显,所有城市的平均贡献率分别为 10%(1.2 μg/m3)、7%(1.5 μg/m3)和 4%(0.16 μg/m3)。为了评估模型选择对这些结果的影响,本研究还考察了模拟分辨率的选择以及气象参数与二氧化氮浓度之间的关系。在使用不同的化学传输模型分辨率(1 × 1 千米到 24 × 24 千米)进行模拟后发现,模型分辨率越高(1 × 1 千米),远离局部排放源的环境空气污染物浓度下降越明显,源贡献比总浓度受到的影响更大。考虑到气象因素,一般来说,低风速(1-2 米/秒)会导致市中心的二氧化氮浓度较高。对于港口距离市中心更近的城市(如伦敦、勒阿弗尔、汉堡和安特卫普),无风条件下的二氧化氮绝对浓度以及航运排放物的贡献率最高。只有当风速低于 6 米/秒时,才会出现高浓度(60 微克/立方米 NO2)。
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引用次数: 0
Source identification of carbon monoxide over the greater Tokyo area: Tower measurement network and evaluation of global/regional model simulations at different resolutions 大东京地区一氧化碳的来源识别:塔式测量网络和不同分辨率的全球/区域模型模拟评估
IF 3.8 Q2 ENVIRONMENTAL SCIENCES Pub Date : 2024-08-01 DOI: 10.1016/j.aeaoa.2024.100284

Because of its relatively long lifetime among short-lived climate forcers in the atmosphere, carbon monoxide (CO) is utilized as a tracer, and is expected to be simulated at coarse resolution. To better grasp the behavior of CO in the atmosphere, multi-altitude measurement is required because the main sources of CO emissions are automobiles (surface) and industry (aloft). In this work, using CO measurements obtained at remote sites and through a tower measurement network in Japan (37 m and 250 m above ground level (AGL) in an urban area, and 32 m AGL at a rural site in the greater Tokyo area), the performances of a global model (2° × 2.5°) and a regional model at various resolutions (12, 4, and 1.3 km) were comprehensively evaluated. The global model successfully simulated CO at remote sites but not for high-concentration peaks at rural and urban sites, whereas the regional model increasingly improved its performance in capturing CO peaks at urban sites with resolutions up to 4 km. Therefore, we concluded that a 4 km resolution was suitable for capturing CO at urban sites, and furthermore estimated the source contributions. The regions surrounding the greater Tokyo area were dominated by the concentration from the lateral boundaries (approximately 180 ppbv), while the higher CO in central Tokyo was attributed to local sources. These local sources accounted for up to 80% of the annual average at the surface level and just 10% aloft (corresponding to the 250 m AGL site). Sensitivity simulations assessing CO sources (automobiles, industry, and others) demonstrated the important role of automobiles, while higher altitudes had more sources attributed to industry. Local sources were found to make more prominent contributions at higher concentration ranges. The appropriate modeling resolution for CO behavior can be drawn from our findings and the usefulness of simultaneous measurements at the surface level and using a tower for capturing the three-dimensional CO structure can be demonstrated as an important approach.

由于一氧化碳(CO)在大气中的寿命相对较长,是一种短寿命的气候影响因子,因此被用作示踪剂,并有望以较高分辨率进行模拟。为了更好地掌握一氧化碳在大气中的行为,需要进行多高度测量,因为一氧化碳的主要排放源是汽车(地面)和工业(高空)。在这项工作中,利用在远程站点和通过日本的塔式测量网络获得的一氧化碳测量数据(城市地区地面以上 37 米和 250 米,大东京地区农村站点地面以上 32 米),对不同分辨率(12、4 和 1.3 千米)的全球模式(2°×2.5°)和区域模式的性能进行了全面评估。全球模式成功地模拟了偏远地区的一氧化碳,但无法模拟农村和城市地区的高浓度峰值,而区域模式在捕捉城市地区一氧化碳峰值方面的性能日益提高,其分辨率最高可达 4 千米。因此,我们认为 4 千米分辨率适合捕捉城市站点的一氧化碳,并进一步估算了源贡献。大东京地区周边区域主要是来自横向边界的浓度(约 180 ppbv),而东京市中心较高的一氧化碳浓度则归因于本地来源。这些本地来源占地面年平均值的 80%,仅占高空年平均值的 10%(与 250 米 AGL 站点相对应)。对一氧化碳来源(汽车、工业和其他)的敏感性模拟评估表明,汽车发挥着重要作用,而更高的海拔则有更多的来源归因于工业。在较高的浓度范围内,本地来源的贡献更为突出。从我们的研究结果中可以得出一氧化碳行为的适当建模分辨率,并证明在地表同时进行测量和使用塔捕捉一氧化碳三维结构是非常有用的重要方法。
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引用次数: 0
National, satellite-based land-use regression models for estimating long-term annual NO2 exposure across India 基于卫星的全国性土地利用回归模型,用于估算印度各地每年的二氧化氮长期暴露量
IF 3.8 Q2 ENVIRONMENTAL SCIENCES Pub Date : 2024-08-01 DOI: 10.1016/j.aeaoa.2024.100289

In India, scarcity of ground-based measurements of nitrogen dioxide (NO2) is a major challenge for estimating long-term exposure and associated health impacts. This study aimed to develop and validate a national-scale annual NO2 exposure model for India for 2019 and determine if model cross-validation predictive ability was improved by including non-continuous (manual) measurements along with reference-grade, continuous measurements.

We used a supervised forward-addition linear regression method to fit land use regression (LUR) models developed with up to 804 Central Pollution Control Board ground monitoring stations (n = 157 continuous, n = 647 manual) and 209 spatial predictor variables, including satellite-based tropospheric NO2 columns. Two models were developed: one using continuous sites only and one using continuous and manual sites, with standard diagnostics and cross-validation (CV) methods. We also assessed if the kriging of final model residuals reduced spatial autocorrelation and improved model CV results. LUR coefficients for the best-performing model were applied to predictors for 2015–2021 and gridded at 100 m to estimate population-weighted exposure.

The continuous sites-only model and combined continuous and manual sites models had CV-R2 values of 0.59 (root-mean-square error [RMSE]: 9.4 μg/m3) and 0.54 (RMSE: 8.3 μg/m3), respectively, and both included the satellite NO2 predictor. Kriging residuals increased the CV-R2 of the combined model to 0.70 (RMSE: 7.2 μg/m3) but offered no improvement for the continuous site model. National population-weighted average NO2 was 22.1 μg/m3 in 2019. We estimated over 92% of the Indian population was exposed to annual NO2 exceeding the WHO air quality guideline (10 μg/m3). In Delhi, Mumbai, and Kolkata, an estimated 45%, 100%, and 100% of the population, respectively, experienced annual NO2 levels that surpassed Indian standards (40 μg/m3). To our knowledge, this is the first such long-term NO2 LUR model specific to India, and predictions are available to interested researchers.

在印度,二氧化氮(NO2)地面测量数据的匮乏是估算长期暴露和相关健康影响的一大挑战。本研究旨在开发和验证 2019 年印度全国范围的年度二氧化氮暴露模型,并确定将非连续(人工)测量值与参考级连续测量值一起纳入模型交叉验证是否会提高模型的预测能力。我们使用了一种有监督的前向添加线性回归方法,以拟合利用多达 804 个中央污染控制委员会地面监测站(n = 157 个连续监测站,n = 647 个人工监测站)和 209 个空间预测变量(包括卫星对流层二氧化氮柱)开发的土地利用回归模型。我们利用标准诊断和交叉验证 (CV) 方法建立了两个模型:一个仅使用连续监测站点,另一个使用连续监测站点和人工监测站点。我们还评估了最终模型残差的克里格化是否降低了空间自相关性并改善了模型 CV 结果。表现最佳模型的 LUR 系数被应用于 2015-2021 年的预测因子,并以 100 米为网格来估算人口加权暴露量。仅连续站点模型以及连续站点和人工站点组合模型的 CV-R2 值分别为 0.59(均方根误差 [RMSE]:9.4 μg/m3)和 0.54(均方根误差:8.3 μg/m3),且均包含卫星 NO2 预测因子。克里格化残差将综合模型的 CV-R2 提高到 0.70(均方根误差:7.2 μg/m3),但对连续地点模型没有任何改进。2019 年全国人口加权二氧化氮平均值为 22.1 μg/m3。我们估计,超过 92% 的印度人口每年暴露在超过世界卫生组织空气质量准则(10 μg/m3)的二氧化氮中。在德里、孟买和加尔各答,估计分别有 45%、100% 和 100%的人口的二氧化氮年浓度超过了印度标准(40 微克/立方米)。据我们所知,这是首个专门针对印度的长期二氧化氮 LUR 模型,感兴趣的研究人员可以使用该模型进行预测。
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引用次数: 0
Evaluation of WRF-Chem PM2.5 simulations in Thailand with different anthropogenic and biomass-burning emissions 对泰国不同人为和生物质燃烧排放的 WRF-Chem PM2.5 模拟的评估
IF 3.8 Q2 ENVIRONMENTAL SCIENCES Pub Date : 2024-08-01 DOI: 10.1016/j.aeaoa.2024.100282

Thailand experiences severe air quality issues, predominantly due to PM2.5 pollution that surpasses WHO guidelines. The main sources are attributed to energy production, industrial activities, vehicular emissions, agricultural burning, and transboundary transport of pollutants. Understanding the transport and transformation of these pollutants is necessary for addressing air quality issues. The Weather Research and Forecasting Model coupled with Chemistry (WRF-Chem) provides information about meteorology, chemical reactions, and transport of trace gases and aerosols. The accuracy of WRF-Chem simulations greatly depends on the choice of anthropogenic and biomass burning emissions inventories. This study provides a detailed evaluation of these inventories to model PM2.5 concentrations in Thailand during both haze and off-haze seasons in 2019. We evaluated WRF-Chem using four anthropogenic emission inventories—CAMS-GLOB-ANT, ECLIPSE, HTAP, and REAS—and four biomass burning emissions inventories—FINN1.5, FINN2.5 MOD, FINN2.5 MODVAR, and QFED—using data from ground-based air quality stations, MODIS AOD, and MOPITT CO satellite data. Our findings suggest CAMS-GLOB-ANT performs optimally for North Thailand, while HTAP and REAS are more effective in Eastern Thailand. For biomass burning, FINN1.5 shows superior performance. The study also highlights the challenge in capturing PM2.5 diurnal variability, particularly due to inaccuracies in simulating the planetary boundary layer height during nighttime in complex terrains. Moreover, our analysis exhibits moderate model performances during the off-haze season while using global and regional anthropogenic emissions in Thailand, emphasizing the need for improving anthropogenic inventories for reliable air quality prediction. For biomass burning emissions, updating emission factors to reflect Thailand's specific vegetation types is recommended to improve WRF-Chem's representation of PM2.5 levels.

泰国面临严重的空气质量问题,主要原因是 PM2.5 污染超过了世界卫生组织的标准。主要来源是能源生产、工业活动、车辆排放、农业焚烧和污染物的跨境运输。要解决空气质量问题,就必须了解这些污染物的迁移和转化。结合化学的天气研究和预测模型(WRF-Chem)提供了有关气象、化学反应以及痕量气体和气溶胶迁移的信息。WRF-Chem 模拟的准确性在很大程度上取决于人为和生物质燃烧排放清单的选择。本研究对这些清单进行了详细评估,以模拟 2019 年雾霾和非雾霾季节泰国的 PM2.5 浓度。我们使用四种人为排放清单--CAMS-GLOB-ANT、ECLIPSE、HTAP 和 REAS,以及四种生物质燃烧排放清单--FINN1.5、FINN2.5 MOD、FINN2.5 MODVAR 和 QFED,利用地面空气质量站数据、MODIS AOD 和 MOPITT CO 卫星数据,对 WRF-Chem 进行了评估。我们的研究结果表明,CAMS-GLOB-ANT 在泰国北部表现最佳,而 HTAP 和 REAS 在泰国东部更为有效。在生物质燃烧方面,FINN1.5 显示出卓越的性能。研究还强调了捕捉 PM2.5 日变化的挑战,特别是由于在复杂地形中模拟夜间行星边界层高度的不准确性。此外,我们的分析表明,在使用泰国的全球和区域人为排放物时,模型在非雾霾季节的表现一般,这强调了改进人为排放物清单以进行可靠的空气质量预测的必要性。对于生物质燃烧排放,建议更新排放因子以反映泰国的特定植被类型,从而改善 WRF-Chem 对 PM2.5 水平的表现。
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引用次数: 0
Methane slip and other emissions from newbuild LNG engine under real-world operation of a state-of-the art cruise ship 新造液化天然气发动机在最先进游轮实际运行中产生的甲烷滑移和其他排放物
IF 3.8 Q2 ENVIRONMENTAL SCIENCES Pub Date : 2024-08-01 DOI: 10.1016/j.aeaoa.2024.100285

Liquefied natural gas (LNG) use as shipping fuel has increased in recent years. While LNG results in lower carbon dioxide (CO2) emissions as well as benefits in terms of air pollutants, the slip of unburned methane, the main component of LNG, has remained a concern. In this study, methane together with other climate warming agents, CO2 and black carbon (BC), as well as other emission compounds were characterized from 4-stroke low-pressure dual fuel engine on-board a newly build cruise ship utilizing LNG as well as marine gas oil (MGO). The brake specific methane slip was found to vary according to engine load, being 2.3–3.0 g/kWh at 54–80% loads, but increasing to 10 g/kWh at 25% load and 21 g/kWh at 12% load. The LNG combustion also resulted in higher formaldehyde emissions compared to MGO, but reduction in formaldehyde levels was observed over the SCR catalyst present in the exhaust line of the dual-fuel engine, without urea injection, suggesting it may provide a pathway for formaldehyde mitigation. In terms of particle emissions, LNG use reduced particle mass (PM) by 87–93% and BC by 94–99% compared to MGO combustion. Non-volatile particle number above 23 nm (PNnv,>23nm) and 10 nm (PNnv,>10nm) were reduced by 88–97% and 97–99%, except at lowest engine load where PNnv,>10nm increased by 26% compared to MGO utilization. When total greenhouse gas (GHG) emissions including CO2 and BC were considered, LNG use resulted in 13–15% lower GHG at high loads, but the benefit was undermined by the escaping methane at low load conditions. Following the engine activity profile during 8-months of vessel operation on the Mediterranean suggested, however, that in a diesel-electric cruise ship, low load conditions are used mainly during arrivals and departures from harbors, as the engine was operated at loads above 40% for 90% of the operation time. Weighted emission factor, representing the actual engine operation, resulted in methane slip of 2.8 g/kWh or 1.7% of the fuel use, which is below the value considered in the FuelEU Maritime. The results suggest that load specific methane slip, together with engine load profile should be considered when evaluating methane slip on vessel or fleet level.

近年来,液化天然气(LNG)作为航运燃料的使用有所增加。虽然液化天然气降低了二氧化碳 (CO2) 排放量,并在空气污染物方面带来了好处,但液化天然气的主要成分--未燃烧甲烷的滑移仍是一个令人担忧的问题。在这项研究中,对一艘使用液化天然气和船用燃气油(MGO)的新建游轮上的四冲程低压双燃料发动机的甲烷、其他气候变暖物质、二氧化碳和黑碳(BC)以及其他排放化合物进行了表征。研究发现,制动比甲烷滑移随发动机负载而变化,在 54-80% 负载时为 2.3-3.0 克/千瓦时,但在 25% 负载时增至 10 克/千瓦时,在 12% 负载时增至 21 克/千瓦时。与 MGO 相比,燃烧液化天然气也会导致更高的甲醛排放,但在双燃料发动机排气管中的选择性催化还原催化剂上观察到甲醛含量的降低,而没有尿素喷射,这表明它可能提供了一种缓解甲醛的途径。在颗粒物排放方面,与燃烧 MGO 相比,使用液化天然气可减少 87-93% 的颗粒物(PM)和 94-99% 的 BC。23纳米(PNnv,>23nm)和10纳米(PNnv,>10nm)以上的非挥发性粒子数分别减少了88%-97%和97%-99%,只有在发动机最低负荷时,PNnv,>10nm比使用MGO时增加了26%。如果考虑到包括二氧化碳和 BC 在内的温室气体(GHG)排放总量,使用液化天然气可使高负荷时的 GHG 排放量降低 13-15%,但低负荷时的甲烷逸散则削弱了这一优势。然而,根据船舶在地中海上运行 8 个月期间的发动机活动曲线显示,在柴油-电力游轮上,低负荷条件主要用于抵港和离港期间,因为发动机在 90% 的运行时间内都在 40% 以上的负荷下工作。代表发动机实际运行情况的加权排放因子导致甲烷滑移量为 2.8 克/千瓦时或燃料使用量的 1.7%,低于 FuelEU Maritime 考虑的值。结果表明,在评估船舶或船队的甲烷滑移时,应考虑特定负载的甲烷滑移以及发动机负载状况。
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引用次数: 0
COVID-19 lockdown impact on air quality and associated health benefit in two contrasting urban cities in Eastern Indo Gangetic Plain COVID-19 封锁对东印度洋平原两个截然不同的城市空气质量的影响及相关健康益处
IF 3.8 Q2 ENVIRONMENTAL SCIENCES Pub Date : 2024-08-01 DOI: 10.1016/j.aeaoa.2024.100290

A key challenge in controlling deteriorating urban air quality is a lack of clear understanding of the regional emissions characteristics and their impact on human health. COVID-19 lockdown provided an opportunity to enhance understanding of background air quality. Towards this, we studied the effect of the lockdown on air pollutants level and associated health benefits in two contrasting urban cities of Eastern IGP, Asansol (industrial) and Kolkata (metropolitan), by analyzing data from 2019 to 2021. The outcomes revealed that the level of exceedance of air pollutants is usually higher in Asansol but significantly decreased in both cities during the lockdown period. Particle concentrations were reduced by 50–70 % compared to Pre-Lockdown and by 20–35 % against the same period in 2019. Kolkata witnessed a higher reduction in PM levels than Asansol. Diurnal variation comparison showed a higher reduction of particle levels during lockdown in the morning at Asansol while in the evening at Kolkata. The health benefits associated with the reduction in PM2.5 concentration were quantified using the BenMAP-CE model, which revealed that improving air quality, like during the lockdown period, would save annually 0.46 and 2.91 deaths per 100,000 persons in Asansol and Kolkata, respectively. Altogether, this study's outcomes provide essential insights to policymakers for regional factors associated to varying air quality and health benefits associated to improvement in air quality.

控制日益恶化的城市空气质量的一个关键挑战是缺乏对区域排放特征及其对人类健康影响的清晰了解。COVID-19 封锁为加强对背景空气质量的了解提供了一个机会。为此,我们通过分析 2019 年至 2021 年的数据,研究了封锁对东部 IGP 的两个对比城市--阿桑索尔(工业城市)和加尔各答(大都市)--空气污染物水平的影响以及相关的健康益处。结果显示,阿桑索尔的空气污染物超标水平通常较高,但在封锁期间,这两个城市的空气污染物超标水平都显著下降。与封锁前相比,颗粒物浓度降低了 50-70%,与 2019 年同期相比降低了 20-35%。加尔各答的可吸入颗粒物浓度降幅高于阿桑索尔。昼夜变化比较显示,在封锁期间,阿桑索尔上午的颗粒物水平降低幅度较高,而加尔各答傍晚的颗粒物水平降低幅度较低。使用 BenMAP-CE 模型对 PM2.5 浓度下降带来的健康效益进行了量化,结果显示,改善空气质量(如在封锁期间)将使阿桑索尔和加尔各答每 10 万人每年分别减少 0.46 和 2.91 例死亡。总之,这项研究的成果为政策制定者提供了重要的见解,帮助他们了解与不同空气质量相关的区域因素以及与改善空气质量相关的健康益处。
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