Characterizing ozone pollution in a petrochemical industrial area in Beijing,China: a case study using a chemical reaction model

This study selected a petrochemical industrial complex in Beijing, China, to understand the characteristics of surface ozone (O₃) in this industrial area through the on-site measurement campaign during the July–August of 2010 and 2011, and to reveal the response of local O₃ to its precursors’ emissions through the NCAR-Master Mechanism model (NCAR-MM) simulation. Measurement results showed that the O₃ concentration in this industrial area was significantly higher, with the mean daily average of 124.6 μg/m³ and mean daily maximum of 236.8 μg/m³, which are, respectively, 90.9 and 50.6 % higher than those in Beijing urban area. Moreover, the diurnal O₃ peak generally started up early in 11:00–12:00 and usually remained for 5–6 h, greatly different with the normal diurnal pattern of urban O₃. Then, we used NCAR-MM to simulate the average diurnal variation of photochemical O₃ in sunny days of August 2010 in both industrial and urban areas. A good agreement in O₃ diurnal variation pattern and in O₃ relative level was obtained for both areas. For example of O₃ daily maximum, the calculated value in the industrial area was about 51 % higher than in the urban area, while measured value in the industrial area was approximately 60 % higher than in the urban area. Finally, the sensitivity analysis of photochemical O₃ to its precursors was conducted based on a set of VOCs/NOx emissions cases. Simulation results implied that in the industrial area, the response of O₃ to VOCs was negative and to NOx was positive under the current conditions, with the sensitivity coefficients of ?0.16~?0.43 and +0.04~+0.06, respectively. By contrast, the urban area was within the VOCs-limitation regime, where ozone enhancement in response to increasing VOCs emissions and to decreasing NOx emission. So, we think that the VOCs emissions control for this petrochemical industrial complex will increase the potential risk of local ozone pollution aggravation, but will be helpful to inhibit the ozone formation in Beijing urban area through reducing the VOCs transport from the industrial area to the urban area.     

大连市夏季近地面臭氧污染数值模拟和控制对策研究

通过区域空气质量模型CAMx对大连市2015年8月近地面臭氧(O_3)污染进行模拟,探讨了O_3及其生成前体物(NOx和VOCs)的来源,O_3生成控制区,并根据敏感性分析结果对前体物排放的控制效果进行了定量评估。结果表明:本地NOx排放对大连地区的NOx浓度贡献占90%以上,本地VOCs排放对大连地区的VOCs浓度贡献占80%以上,而本地NOx和VOCs排放对大连地区O_3浓度贡献仅占29%;大连市整体上为VOCs控制区,控制VOCs能有效降低O_3污染,还能有效削减O_3的峰值浓度;通过敏感性分析结果计算得出,削减大连本地工业源VOCs和民用源VOCs能够有效降低大连地区O_3浓度,削减10%的工业源VOCs能使市区O_3平均浓度降低2%左右,削减10%的民用源VOCs能使大连市区平均O_3浓度降低1%左右。建议NOx与VOCs削减比例为1∶2,对大连市O_3和PM2.5污染进行协同控制。     

The changes in different ozone metrics and their implications following precursor reductions over northern Taiwan from 1994 to 2007

The changes of different O₃ metrics such as O_{3_avg} (daily mean), O_X (NO₂ + O₃), O_{3_8h} (daily maximum 8-h moving average), O_{3_max} (daily maximum 1-h average), and exceedances of O_{3_8h} and O_{3_max} at 16 air quality monitoring stations over northern Taiwan from 1994 to 2007 are evaluated. The O_{3_avg} at the background site displays an increasing trend at 0.54 ±0.21 ppb (1.28 ±0.49%) per year. The O_X at urban sites shows a significant increase, indicating that even with the effect of reduced NO titration increasing photochemical production is evident. The exceedances of O_{3_8h} (>80 ppb) are about 14.9% higher than O_{3_max} (>120 ppb) with more exceedances at coastal or background sites, where the anthropogenic O₃ precursor emissions are lower. In addition to increasing background O₃ and reductions in NO titration, increasing O₃ production efficiency also plays a key role in the increase of moderate to high O₃ concentrations. The findings help explain the different trends in exceedances and levels of O_{3_8h} and O_{3_max} and are likewise important in the formation of O₃ control strategies.     

Anthropogenic emissions of methane and nitrous oxide in the Federal Republic of Germany

The anthropogenic emission sources of methane (CH₄) and nitrous oxide (N₂O) in the Federal Republic of Germany were investigated. The object of the recently completed first phase of this research project was to summarize the present knowledge about the emission sources, make a first rough estimate of the emissions, identify the need for further research in the field, and - as far as possible - discuss the existing possibilities to reduce emissions. The main CH₄ emission sources identified are the landfills, stock farming and pit mining, the main N₂O sources are agriculture (including a minor contribution from animal wastes) and the production of adipic acid, the latter possibly being reducible by means of a new catalytic process. The total anthropogenic emissions of CH₄ from Germany are estimated at 5.4 – 7.7 million tonnes per year, contributing a share of roughly 2 % to the world-wide anthropogenic emissions (350 million t/a). Those of N₂O are estimated at 200 000 – 280 000 tonnes per year (world-wide 1.4 – 6.5 million t/a).     

The Climate Impacts of Sulfate Aerosols

Sulfate aerosols (SO₄) from anthropogenic emissions of sulfur dioxide (SO₂) generally have a cooling effect. However, if SO₂ emissions fall over time, accounting for sulfate aerosols will increase the predicted warming from greenhouse gases. This paper integrates the four marker emission scenarios for CO₂ and SO₄ from the Special Report on Emissions Scenarios (SRES), the UIUC general circulation model (GCM), and a country-specific impact model (GIM) to calculate the impacts of sulfate aerosols. By 2100, lower SO₂ emissions slightly increase warming in the temperate and polar regions causing small damages in the former and small benefits in the latter. If SO₂ emissions are also lower in tropical regions, temperatures will rise causing small damages there as well. However, if SO₂ emissions rise in tropical regions, temperatures will fall leading to small benefits. This revised version was published online in July 2006 with corrections to the Cover Date.     

Industrial point source CO<Subscript>2</Subscript> emission strength estimation with aircraft measurements and dispersion modelling

CO₂ remains the greenhouse gas that contributes most to anthropogenic global warming, and the evaluation of its emissions is of major interest to both research and regulatory purposes. Emission inventories generally provide quite reliable estimates of CO₂ emissions. However, because of intrinsic uncertainties associated with these estimates, it is of great importance to validate emission inventories against independent estimates. This paper describes an integrated approach combining aircraft measurements and a puff dispersion modelling framework by considering a CO₂ industrial point source, located in Biganos, France. CO₂ density measurements were obtained by applying the mass balance method, while CO₂ emission estimates were derived by implementing the CALMET/CALPUFF model chain. For the latter, three meteorological initializations were used: (i) WRF-modelled outputs initialized by ECMWF reanalyses; (ii) WRF-modelled outputs initialized by CFSR reanalyses and (iii) local in situ observations. Governmental inventorial data were used as reference for all applications. The strengths and weaknesses of the different approaches and how they affect emission estimation uncertainty were investigated. The mass balance based on aircraft measurements was quite succesful in capturing the point source emission strength (at worst with a 16% bias), while the accuracy of the dispersion modelling, markedly when using ECMWF initialization through the WRF model, was only slightly lower (estimation with an 18% bias). The analysis will help in highlighting some methodological best practices that can be used as guidelines for future experiments.     

工业园区和城区VOCs组成及化学活性的空间差异对清远大气臭氧污染分布的影响

工业化与城镇化交替演进使珠三角及其周边地区土地利用类型较为复杂。快速的城市化进程使城市建成区与大量村镇工业园区互相交错。这种变化势必会增加挥发性有机物(VOCs)在组分构成和空间分布上的复杂性,并对臭氧(O₃)污染的时空变化产生影响。为厘清这种排放的空间异质性特征及其对O₃污染分布的影响,分别选取可以代表清远市典型工业园区和城市建成区的站点开展观测研究。结果表明:工业园区和城市建成区VOCs浓度水平和污染特征有较大的空间差异,其中代表村镇工业园区的龙塘站VOCs日均浓度为30.42×10^-9,高于代表城市建成区的技师学院站(17.32×10^-9)。龙塘站二甲苯和甲苯的臭氧生成潜势(OFP)比技师学院站高57.6×10^-9,且该值相当于技师学院站排名前10位物种OFP的总和。气象分析表明:2个站点之间并非彼此的上、下风向,而是共同受到局地气团的影响。源解析结果表明:源排放是造成这种空间异质性的内因,其中交通源对技师学院的贡献更高,而工业相关排放源对龙塘的贡献更高。该研究进一步比较了周边站点O₃时间序列的一致性,并模拟2个站点的O₃生成速率。研究发现O₃在局地范围内变化较小,高VOCs排放的地点对局地O₃有较高的贡献,局地内不同地点的O₃生成过程也存在较大差异。据此,笔者提出O₃污染防控建议:短期内可通过技术手段和观测数据发现O₃污染的重要贡献点,并进行针对性的"散乱污"清理整治和涉VOCs行业综合整治,长期看应科学合理规划城市发展布局和产业布局,预留城市通风廊道,以有效减少O₃污染。     

试点城市O3浓度特征分析

利用2009年O3试点城市的03监测数据,分析了北京、天津、上海、青岛、沈阳和广东的03浓度变化特征,统计了年超标情况,并结合气象要素数据分析了其对03浓度的影响.结果表明,不同城市各点位间03浓度变化趋势基本一致,但因点位类型不同,浓度存在差异；O3浓度呈单峰型日变化,在13:00-15:00出现最大值,6:00-7:00出现最小值；O3超标主要集中在4-8月份,广州和北京超标现象较多；O3浓度受温度、降水、风速和风向等气象要素影响较大.     

郑州市PM2.5浓度时空分布特征及预测模型研究

利用统计学原理和GIS技术,对郑州市2013年8月17—12月31日期间PM2.5浓度时空分布特征进行分析,同时结合气象资料与前一日污染数据,建立人工神经网络反向传播算法模型(BP-ANN)和多元线性回归模型用于该市细颗粒物污染的短期预测。结果表明,郑州市PM2.5浓度日变化呈单峰模式,随逆温现象的发生和交通的密集于上午11:00达到峰值,午后逐步下降。在工作日、周末与国庆节的对比中,国庆节期间颗粒物污染浓度高出平日32.8%,表明人为活动的加剧影响PM2.5的排放;周末与工作日期间无显著差异。在空间分布上,金水区、管城回族区污染最为严重,工业燃煤、地铁施工等源排放是造成污染的主要原因;位于远郊的岗里水库,受秸秆焚烧和市区污染输送等影响,PM2.5浓度亦维持较高水平。最后,研究将所构建的BP-ANN预测模型和多元线性回归模型对比,结果发现两模型在建模阶段预测值与真实值的拟合一致性指标分别为0.944、0.918,均方根误差分别为59.788、70.611;验证阶段拟合一致性指标分别为0.854、0.794,平均绝对误差分别为25.298、32.775,表明BP-ANN模型在预测郑州市PM2.5污染过程中更具优势。     

中国城市臭氧的形成机理及污染影响因素研究进展

中国城市臭氧(O_3)污染问题日趋严重。O_3主要来源于汽车尾气及工业排放氮氧化合物(NO_x)和挥发性有机物(VOCs)光化学反应生成,少部分来自于平流层的向下传输。文章介绍了城市O3形成机理研究情况,概述了中国城市臭氧污染浓度特征及气象因子、气候变化、前体物等影响因素研究进展情况,并对未来研究方向进行了展望。     

基于火点辐射能量的2017—2021年广西秸秆露天燃烧排放时空分析

基于2017—2021年MODIS、VIIRS和Himawari-8等多套卫星的火点辐射能量(FRE)和云量反演数据,使用更高分辨率的火点替代相邻位置低分辨率火点的融合方法,利用晴空的火点分布数据对被云遮蔽的区域进行补偿,核算得到了2 km高分辨率的广西秸秆露天燃烧排放数据,并针对2017—2021年的广西秸秆露天燃烧排放量展开精细的时空分布研究。结果表明:2017—2021年广西秸秆露天燃烧的CO、NO_x、SO₂、NH₃、VOCs、PM₁₀和PM_2.5的年排放量均值分别为12.91万、0.78万、0.16万、0.17万、2.77万、2.26万、2.21万t,排放高值区域分布在广西中部及西南部。秸秆露天燃烧排放的主要时间集中在冬、春季节(10月至次年3月),时值晚稻收割期和甘蔗榨季,占全年排放量的60%以上。广西秸秆露天燃烧PM_2.5年均排放量是全广西PM_2.5人为源年排放量的8.74%,通过逐日排放贡献分析发现,秸秆露天燃烧具有短期排放量较大的特点,2017—2021年,在1—2月有34 d出现秸秆露天燃烧导致PM_2.5排放量超过人为源排放量50%的情况。     

Ozone Indicators Determined at Rural Sites in the Eastern United States by two Monitoring Networks

Ozone levels at Clean Air Status andTrends Network (CASTNet) and nearby rurally-designatedState and Local Air Monitoring Stations (SLAMS) siteslocated in the eastern United States (U.S.) arecompared using daily indicators (i.e., maximum, range,and SUM06) based on hourly O₃ measurements. Comparisons are also made using monthly and summertimethree-month SUM06 determinations aggregated from dailydata. Comparison of O₃ indicators at the pairedCASTNet-SLAMS sites generally shows better agreementfor O₃ maximum than for range or SUM06. Thehighest correlation of daily O₃ indicators occursfor paired sites that are separated by less than 100miles, and the correlation diminishes with increasingseparation distance. Correlation coefficients exceed0.70 in 49% of the comparisons of maximum, in23% of range comparisons and in 5% ofSUM06 comparisons, suggesting that substitution ofSLAMS for CASTNet O₃ measurements would fail tocapture a substantial amount of the variability inO₃ indicators present at the CASTNet sites. Correlations of O₃ indicators at CASTNet andpaired nearby SLAMS sites are 0.80 in a relativelysmall number of cases. Despite the high correlationin even these cases, O₃ behavior at paired sitesis not identical and shows systematic differences thatare reflected in the O₃ minimum, hourly averageconcentrations, and the monthly and three-month SUM06. Ozone measurements at nearby rurally-designated SLAMSsites may not capture the `rural' nature of the airquality being monitored at CASTNet sites and, in mostcases, may not be sufficiently representative of theconcentration at CASTNet sites to permit O₃measurements at SLAMS sites to be used in lieu ofmeasurements at CASTNet sites. As a result, if ruralO₃ concentration data are needed, then O₃monitoring at carefully chosen, rurally representativesites is recommended.     

空气质量多模式预报系统在中山市的应用

介绍了中山市空气质量多模式预报系统。对2015年3月—2016年2月的预报效果评估表明:系统可以较好地反映污染物的变化趋势但仍存在系统性偏差。通过对排放源清单的调整优化及对模式干沉降模块的改进使模式系统的偏差显著减小。总结并建立中山市污染天气案例库,发现在典型污染天气形势下,除O3-8 h外,其他污染物均值均能达到空气质量二级标准。未来将从2个方面提高中山市空气质量预报预警系统的实用性,包括逐步实现污染源排放清单的动态及时更新和提高极端气象条件下O3污染预报能力。     

Is Globalization Detrimental to CO<Subscript>2</Subscript> Emissions in Japan? New Threshold Analysis

Using annual data from 1970 to 2014, this paper examines the effects of globalization on CO₂ emissions in Japan while accounting for economic growth and energy consumption as potential determinants of carbon emissions. The structural breaks and asymmetries arising due to policy shifts require attention, and hence, an asymmetric threshold version of the ARDL model is utilized. The results show the presence of threshold asymmetric cointegration between variables. Threshold-based positive and negative shocks arising from globalization increase carbon emissions, while the impact of the latter is more profound. Energy consumption (economic growth) also has a significant positive effect on carbon emissions. Globalization, economic growth, and energy consumption significantly increase carbon emissions in the short run. We suggest that policy makers in Japan consider globalization and energy consumption as policy tools in formulating their policies regarding protecting sustainable environmental quality in the long run. Otherwise, the Japanese economy may continue to face environmental consequences such as undesirable climate change and massive warming at the micro and macro levels as a result of potential shocks arising from globalization and energy consumption.     

Differences in the Spatial Distribution and Chemical Composition of PM10 Between the UK and Poland

The Fine Resolution Atmospheric Multi-pollutant Exchange Model was used to calculate the spatial distribution and chemical composition of PM₁₀ concentrations for two geographically remote countries in Europe—the UK and Poland—for the year 2007. These countries are diverse in terms of pollutant emissions as well as climate conditions. Information on the contribution of natural and anthropogenic as well as national and imported particles in total PM₁₀ concentrations in both countries is presented. The paper shows that the modelled national annual average PM₁₀ concentrations, calculated for the entire country area, are similar for the UK and Poland and close to 12 μg m^?3. Secondary inorganic aerosols dominate the total PM₁₀ concentrations in Poland. Primary particulate matter has the greatest contribution to total PM₁₀ in the UK, with large contribution of base cations. Anthropogenic sources predominate (81 %) in total PM₁₀ concentrations in Poland, whereas natural prevail in the UK—hence, the future reduction of PM₁₀ air concentrations by emissions reduction could be more difficult in the UK than in Poland.     

Long-term spatiotemporal patterns of CH4 and N2O emissions from livestock and poultry production in Turkey

This study quantified spatiotemporal patterns of CH₄ and N₂O emissions from livestock and poultry production in Turkey between 1961 and 2007. CH_4(enteric) (from enteric fermentation), CH_4(manure) (from manure management), and N₂O_(AWM) (from animal waste management) emissions in Turkey were estimated at 1,164, 216, and 55 Gg in 1961 and decreased to 844, 187, and 39 Gg in 2007, contributing a share of roughly 2% to the global livestock-related CH₄ emissions and %1.5 to the global N₂O_(AWM) emissions, respectively. Total CO₂-eq emissions were estimated at 50.7 Tg in 1961 and declined from a maximum value of 60.7 Tg in 1982 to a minimum value of 34.5 Tg in 2003, with a mean emission rate of 48 Tg year^???1 due to a significant reduction in the number of ruminant livestock. The highest mean share of emissions belonged to West Black Sea (14% and 16%) for CH_4(enteric) and CH_4(manure) and to North East Anatolia (12% and %13) for N₂O_(AWM) and total CO₂-eq emissions, respectively. The highest emission density was 1.7 Mg km^???2 year^???1 for CH_4(enteric), 0.3 Mg km^???2 year^???1 for CH_4(manure), and 0.07 Mg km^???2 year^???1 for the total CO₂-eq emissions in the West and North East Anatolia regions and 0.09 Mg km^???2 year^???1 for N₂O_(AWM) in the East Marmara region. Temporal and spatial variations in CH_4(enteric), CH_4(manure), and N₂O_(AWM) emissions in Turkey were estimated using regression models and ordinary kriging at a 500-m resolution, respectively.     

中原城市群臭氧浓度分布特征及来源

利用2015年臭氧(O_3)自动监测数据和源排放清单,分析了中原城市群O_3浓度的空间、时间分布情况,探讨了中原城市群中城市间O_3的相关性,以及O_3浓度、NOx、VOCs、CO及汽车保有量间的相关性。指出中原城市群是全国更是河南O_3污染的严重地区,O_3浓度年内月度变化呈倒"V"型分布,具有明显的北部城市特征;中原城市群9个城市间除开封外其他8个城市间都呈高度正相关性,相关系数均为0.892~0.991;9个城市机动车保有量及NOx、VOCs和CO等前体物的年排放量与其年均O_3浓度之间存在正相关性。分析认为,NOx、VOCs和CO等前体物的排放是中原城市群O_3浓度偏高的主要影响因素,同时O_3浓度也与日照时间、降雨量、植物源VOCs排放量及相邻城市间污染物的空间输送等因素有着密切的关系。     

Characterization of ambient ozone and its precursors around a coking plant

The local-scale relationship between ambient ozone (O₃) and its precursors was examined around a coking plant in northern China. The upwind, plant boundary, and downwind locations were selected for investigation during the summer and autumn seasons in 2012. It was found that propene, toluene, and benzene were the top three non-methane hydrocarbon (NMHC) species for O₃ formation at plant boundary, while propene, toluene, and m/p-xylene were the top three NMHC species at downwind location. Isoprene was the dominant species for O₃ formation at upwind location. It was also found that an O₃ depressing process occurred at plant boundary as a result of high NO emissions. Both local photochemistry and transport led to O₃ accumulation at the downwind locations. The variation of NMHC concentration during O₃ polluted and non-polluted episodes was investigated, and it indicated that NMHC concentration was higher during non-polluted episodes than polluted episodes. The impacts of precursors on O₃ formation under different meteorological conditions were also examined.     

Modelling the contribution of different sources of sulphur to atmospheric deposition in the United Kingdom

In order to understand relationships between sources and receptors of atmospheric deposition, computer models must be used. This paper describes a Lagrangian acid deposition model that represents emissions of trace species across Northern Europe. The chemistry of sulphur dioxide, dimethyl sulphide and hydrogen sulphide is represented and the model tested against estimates of UK wet and dry deposition. Mean UK wet and dry deposition for the period 1992–1994 was 206 and 145 ktonne S yr^-1, respectively. The model predicted wet and dry deposition of 222 and 166 ktonne S yr^-1, in good agreement with measurements. The model has been used to examine the sources of deposited S to the UK. For a base year of 1992, 86% of the UK's SO₂ emissions are exported. The S deposition attributable from mainland European sources was 36% of the UK total S deposition, in good agreement with other UK models but this differs substantially from the calculations of the EMEP model. Natural sources of S deposition from planktonic emissions of dimethyl sulphide, biological emissions of hydrogen sulphide and non-eruptive volcanic emissions of sulphur dioxide contributed approximately 1% of the modelled UK S deposition, of which 95% originated from dimethyl sulphide. The explicit chemical scheme for dimethyl sulphide incorporated into the model showed that 24% of the resultant deposited S was methane sulphonic acid. Boundary conditions of the model were tested and it was found that initialisation of sulphur dioxide and sulphate concentrations to representative ambient conditions had a very small effect. The modelled contribution of UK and European sources to UK S deposition was approximately 40 and 60%, respectively, showing the dramatic change arising from projected UK SO₂ emissions in 2010. This revised version was published online in July 2006 with corrections to the Cover Date.