2015—2021年广州地区近地面O3浓度污染特征及其与气象因素关系

利用2015—2021年广州地区近地面逐时臭氧（O₃）观测资料及同期地面气象站常规观测数据,分析了广州地区近地面O₃浓度污染特征及其与气象因素的关系.结果表明：2015—2021年广州地区O₃浓度呈缓慢上升趋势,增速为1.9 μg?m^-3?a^-1,2015和2019年O₃浓度超标天数 最多;O₃平均浓度季节变化明显：秋季＞冬季＞夏季＞春季;O₃浓度空间分布不均匀,城郊地区高于中心城区;峰值中心位于城郊地区白云区,低值中心位于中心城区荔湾区.O₃浓度高峰期是7—10月,9月浓度最高,3月浓度最低;四季O₃浓度日变化均呈“单峰型”结构,最低值出现在7：00—8：00,14：00—16：00达到峰值.近地面O₃平均浓度和O₃超标率均与气温呈正比,当气温＞15 ℃开始出现臭氧超标现象.相对湿度＜50%时,O₃超标率与相对湿度呈正比;相对湿度为40%~50%时,O₃超标率达峰值为16.3%.当风速＜2 m?s^-1时,O₃超标率与风速呈正比;当风速＞ 2 m?s^-1时,O₃超标率与风速呈反比.高温、低湿、风小是广州地区产生高浓度O₃的主要气象因子.     

加油站油气处理装置VOCs化学组成及二次污染生成贡献

加油站油气处理装置是控制埋地油罐油气压力并对油气进行回收处理的装置,测试分析油气处理装置进口和出口挥发性有机物(VOCs)化学组成,利用最大增量反应活性(MIR)和气溶胶生成系数(FAC)估算VOCs的臭氧生成潜势(OFP)和二次有机气溶胶生成潜势(SOAP),量化评估其二次污染生成贡献.结果表明：(1)油气处理装置进口和出口ρ(TVOC)分别为436～706 g·m^-3和4.98～10.04 g·m^-3,VOCs排放主要为烷烃(72%±4%)、含氧有机物(14%±2%)和烯烃(11%±5%).不同处理工艺VOCs排放差异较小,关键物种均为异戊烷(约25%),其次为正丁烷、异丁烷和正戊烷.(2)油气处理装置出口排放的VOCs臭氧生成系数(SR值)为2.6～3.3 g·g^-1,OFP为3.5～25.6 g·m^-3,其中烯烃对OFP贡献率(43%～69%)最大,其次为烷烃(20%～35%)和含氧有机物(10%～22%),OFP主要贡献物种为丁烯、顺-2-丁烯、反-2-丁烯、异戊烷和丙醛.(3)油气处理装...     

不同浓度臭氧对单颗粒气溶胶化学组成的影响

为探讨高浓度臭氧(O₃)对气溶胶生成与老化过程的影响,本研究利用单颗粒气溶胶质谱仪(SPAMS)于2018年10月在广东省鹤山大气环境超级监测站进行观测.观测期间根据O₃浓度的高低,定义了高臭氧浓度(P_H)时段和低臭氧浓度(P_L)时段,其中P_H时段O₃平均浓度为117μg·m^-3,P_L时段平均浓度为25μg·m^-3.依据化学组成的不同,观测期间单颗粒主要包含老化元素碳颗粒(EC-aged)、二次颗粒(Sec)和老化有机碳颗粒(OC-aged).P_H时段单颗粒总数(348 085)高于P_L时段(224 797),且P_H时段Sec颗粒(37.1%)的占比显著高于P_L时段(27.8%),而EC-aged颗粒(32.1%)则低于P_L时段(44.1%),OC-aged颗粒(13.5%)略高于P...     

Ozone Episode in the Milan Metropolitan Area A Comparative Evaluation of UAM-V and CALGRID Models

Data from an ozone episode (2–5 June, 1998) in the Milan metropolitan area were used for an application of two photochemical grid models: UAM-V and CALGRID. To assure a fair comparison, the models were run on the same domain and grid size, with same source emission inputs, CALMET diagnostic meteorology, and initial and boundary conditions taken from air quality data and literature values. Hourly emissions were derived from the AutoOil-II programme inventory except for on-road mobile source emissions; a new traffic emission inventory, based on both COPERT II methodology and road classification has been developed. NO_x and O₃ concentration results were compared to local network monitoring data. Results indicate that both models predict the highest ozone values along the north-east direction and are able to reproduce the ozone daytime trend though differences can be found between the two models on ozone spatial distribution. Average normalised bias for both models is about 50%, peak daily ozone concentrations are underestimated, with simulated peak shapes broader than the observed ones and a temporal shift between the two models. Night-time concentration levels of pollutants were not successfully reproduced due to an incorrect parameterisation of vertical turbulence calling for further work.     

The effect of elevated UV-B (280–320 nm) radiation levels on Silene vulgaris: A comparison between a highland and a lowland population

Highland (altitude 1600 m above sea level) and lowland (altitude −2 m below sea level) populations of the perennial herb Silene vulgaris (Moench) Garcke, were tested on their response to elevated levels of UV-B radiation. Highland populations typically receive high natural UV-B fluxes, whereas lowland populations receive a lower natural UV-B dose. Adaptation to high UV-B levels of the highland population is to be expected. Experimental comparison of growth rates, gas exchange rates, transpiration and biochemical parameters using adult plants as well as seedlings did not show a difference in the response to elevated UV-B levels between the two populations. Individuals of both populations were relatively insensitive to elevated UV-B radiation. The response of alpine and lowland populations of Silene vulgaris is discussed in relation to the dispersal of this species after the last ice age.     

Ozone Deposition to a Coniferous and Deciduous Forest in the Czech Republic

Estimates of ozone concentration and deposition flux to coniferous and deciduous forest in the Czech Republic on a 1 × 1 km grid during growing season (April–September) of the year 2001 are presented. Ozone deposition flux was derived from ozone concentrations in the atmosphere and from its deposition velocities. To quantify the spatial pattern in surface concentrations at 1 km resolution incorporating topography, empirical methods are used. The procedure maps ozone concentrations from the period of the day when measurements are representative for the forest areas of countryside. The effects of boundary layer stability are quantified using the observed relationship between the diurnal variability of surface ozone concentration and altitude. Ozone deposition velocities were calculated according to a multiple resistance model incorporating aerodynamic resistance (R _a ), laminar layer resistance (R _b ) and surface resistance (R _c ). Surface resistance (R _c ) comprises stomatal resistance (R _sto ). R _sto was calculated with respect to global radiation, surface air temperature and land cover. Modelled total and stomatal ozone fluxes are compared with the maps describing equivalent values of AOT40 (accumulated exposure over threshold of 40 ppb). For forests, the critical level (9,000 ppbh May–July daylight hours) is exceeded over 50% of forested territory. This indicates the potential for effects on large areas of forest. There is significiant correspondence between the exposure index AOT40 and the total ozone flux, but the relation between the total ozone flux and AOT40 exposure index is not clear in all parts of the forest territory.     

消除DPD法测定水中臭氧浓度干扰因素的研究

研究了Ｈ_２Ｏ_２和其它氧化剂（以过氧化苯甲酰为例）对ＤＰＤ法测定水中臭氧浓度的干扰作用，结果表明，随着ＫＩ浓度或显色时间的增加，Ｈ_２Ｏ_２和其它氧化剂的干扰作用增加，当ＫＩ浓度为０．５ｇ／Ｌ时，可以基本消除这些干扰作用，且当臭氧浓度低于０．６ｍｇ／Ｌ时，不影响臭氧对ＤＰＤ的显色作用。     

Relationships between emission sources and air mass characteristics in East Asia during the TRACE-P period

Long-range transport of pollutants influenced by anthropogenic and natural emission sources in East Asia is investigated by using backward trajectory analysis along the NASA TRACE-P flight tracks and a numerical simulation with the three-dimensional chemical transport model (STEM-2k1). Observation-based regional distributions of trace gases are reconstructed using the observations obtained by measurements on board the DC-8 and P3-B aircrafts. Systematic features of the spatial distribution for each species are identified. It is found that the observed concentrations of CO and some NMHCs, and the ratios between these species, are highly associated with the source distribution features and their regional characteristics. Reconstructed fields of the observed and modeled ethane/CO and ethane/propane are found to reproduce well the estimated emission ratios in East Asia. We also investigated the time rate of change of the concentration of species and their ratio along the trajectory. From this analysis the propane/ethane and propane/acetylene ratios are shown to preserve their emission ratios during regional transport. However systematic differences in the propane vs. acetylene/CO relationships are found between the model and observation values. This analysis suggests that further efforts are needed to improve the estimates of biomass burning emissions in SE Asia. The results presented in this paper also suggest ways to further extend the capabilities to derive observation-based inventories.     

臭氧光催化降解地下水中天然有机物的研究

在现场开展了中试规模的臭氧光催化降解天然有机物的研究。研究表明，对大分子天然有机物占很大比例且重碳酸盐含量较高的地下水，臭氧投加量10mg／L和反应时间10min条件下，TOC的去除率不到20％，但uV254和三卤甲烷生成潜力（THMFP）去除率分别达到近60％和33．5％。臭氧光催化与活性炭吸附相连，能显著提高UV254的THMFP的去除率，但TOC去除率并不明显高于单独活性炭吸附。臭氧光催化使大分子有机物转化为小分子有机物，后者在活性炭上的吸附性提高且生化性改善，可望在生物活性炭上更有效地去除。     

Ground level ozone concentrations and its association with NOx and meteorological parameters in Kathmandu valley, Nepal

This paper summarizes the results of a yearlong continuous measurements of gaseous pollutants, NO, NO₂, NO_x and O₃ in the ambient air at Kathmandu valley. Measured concentration of the pollutants in study area is a function of time. NO, NO₂ and O₃ peak occurred in succession in presence of sunlight. At the time of maximum O₃ concentration most of the NO_x are utilized. The diurnal cycle of ground level ozone concentrations, revealed mid-day peak with lower nocturnal concentrations and inverse relationship exists between O₃ and NO_x, which are evidences of photochemical O₃ formation. The observed ground level ozone during monsoon is slight lower than the pre-monsoon value. Further, lack of rainfall and higher temperature, solar radiation in the pre-monsoon have given rise to the gradual build up of ozone and it is lowest during winter. Ground level ozone concentrations measured during bandha (general strike) and weekend are 19% and 13% higher than those measured during weekdays. The most effective ozone abatement strategy for Kathmandu Valley may be control of NO_x emissions.