盐城市区环境空气污染原因分析及对策建议

通过对盐城市区建成空气自动监测站来的数据分析,简要说明了盐城市区环境空气质量下降的原因,并提出了改善城市大气污染的建议措施。     

空气自动站气路系统常见的故障及排除方法

以API空气自动监测站为例，介绍了该仪器在使用以及保养过程中，气路系统中常见的故障，分析了故障产生的原因，并提出排除的方法。     

环境空气质量自动监测站的管理与维护

随着工业化、城镇化的深入推进,二氧化硫、氮氧化物、烟粉尘和挥发性有机物等各类污染物排放到环境中,致使中国大气受到严重污染,给人体的健康、动植物的生长、发育和繁殖等带来负面的影响。为实时监测环境空气质量,建立环境空气质量自动监测站逐渐成为大气污染防治的主要手段。文中以环境空气质量自动监测站为研究对象,提出环境空气质量自动监测站管理与维护面临的问题,探讨相应的解决措施,以期为环境空气质量自动监测站的管理与维护提供参考依据。     

空气自动站存在的问题及解决办法

空气自动站是一套以在线自动分析仪器为核心,运用现代传感技术、自动测量技术、自动控制技术、计算机应用技术以及相关的专用分析软件和通信网络组成的综合性的在线自动监测体系。但是,由于大气自动监测站纯粹是靠自动监测仪器的24 h不间断的运行,经分析得出数据,所以如何保证自动监测仪器的正常运行,已成了大气自动站的日常工作中的重点。现以金湖县大气自动站在运行中出现的一些问题为例,在查阅资料,结合实际情况,得出一些导致大气自动站运行不正常的原因及解决的方法。     

水质自动监测站的取水问题及其处理方法

对水质自动监测站取水问题及常见原因进行了较为全面的分析和研究，并针对性的提出了解决办法。     

空气自动监测系统软件开发及数据整合模式探讨

空气自动监测系统的仪器仪表多样化，以及数据采集装置和数据格式的差异，给系统软硬件的集成，以及数据应用和管理带来了不便，也是构成空气自动监测信息化进程中的技术瓶颈之一，通过对空气自动监测系统软件开发和数据整合模式的对比分析，探讨了解决问题的途径。     

环境空气流动监测车的改造与应用

空气流动监测技术,是近年来快速发展的自动监测技术之一,在自动监测领域应用广泛。文中通过实例,介绍了南京市空气流动监测车在监测服务中的应用。     

随身自动空气净化处理器的研究

随身自动空气净化器,采用了活性炭、光催化技术相结合的空气过滤装置.空气污染传感器与单片机组成空气质量监测电路,当空气污染超标时,产生语音提示,液晶屏显示空气质量的等级,自动(或手动)控制引风机工作,供给个人清新无污染的空气.     

随身自动空气净化处理器的研究

随身自动空气净化器，采用了活性炭、光催化技术相结合的空气过滤装置。空气污染传感器与单片机组成空气质量监测电路，当空气污染超标时，产生语音提示，液晶屏显示空气质量的等级，自动（或手动）控制引风机工作，供给个人清新无污染的空气。     

树林对大气污染扩散的影响

城市的大气监测网络按社会功能区设点,其中,大气质量背景(或清洁区对照)监测点,传统上设在风景区,且总是设在树林比较繁茂的地点。近年来,随着环境保护科学的发展,城市大气环境质量地面自动监测站逐渐增多。按各功能区设自动监测子站,监测仪采样器架在子站屋顶上,清洁区的采样器为避免树蓬的遮掩,一般置于和树顶齐平的高度。然而,清洁区对照点出现了始料不到的情况。     

The reciprocal relation between lightning and pollution and their impact over Kolkata, India

Aerosol loading in the atmosphere can cause increased lightning flashes, and those lightning flashes produce NO _X , which reacts in sun light to produce surface ozone. The present study deals with the effect of surface pollutants on premonsoon (April–May) lightning activity over the station Kolkata (22.65° N, 88.45° E). Seven-year (2004–2010) premonsoon thunderstorms data are taken for the study. Different parameters like aerosol optical depth and cloud top temperature from the Moderate Resolution Imaging Spectroradiometer satellite products along with lightning flash data from Tropical Rainfall Measuring Mission’s (TRMM) Lightning Imaging Sensor are analyzed. Some surface pollution parameters like suspended particulate matter, particulate matter 10, nitrogen oxides (NO _X ), and surface ozone (O₃) data during the same period are taken account for clear understanding of their association with lightning activity. Heights of convective condensation level and lifting condensation level are collected from radiosonde observations to anticipate about cloud base. It is found that increased surface pollution in a near storm environment is related to increased lightning flash rate, which results in increased surface NO _X and consequently increased surface ozone concentration over the station Kolkata.     

Lightning-tropospheric ozone connections: EOF analysis of TCO and lightning data

An empirical orthogonal function (EOF) analysis is applied to two different data sets of tropospheric column ozone (TCO) and observed lightning flash rates over the tropical Atlantic for the period of 1996–2000. The first two dominant EOF modes of TCO values, explaining more than 65% of total variance are characterized by the seasonal cycle. The time series of EOF1 and EOF2 of TCO values are in phase with those of the EOF2 (16%) and EOF1 (63%) of the lightning, respectively. These relationships imply the influence of lightning on the tropical ozone maximum and the tropical ozone paradox. Moreover, the spatial distribution of the EOF modes and the horizontal wind field in the upper troposphere show that the highest lightning flash rates are located upstream of the region where high TCO values are found throughout the year.     

Dynamic-chemical coupling of the upper troposphere and lower stratosphere region

The importance of the interaction between chemistry and dynamics in the upper troposphere and lower stratosphere for chemical species like ozone is investigated using two chemistry-climate models and a Lagrangian trajectory model. Air parcels from the upper troposphere, i.e. regions of lightning and aircraft emissions, are able to be transported into the lowermost stratosphere (LMS). Trajectory calculations suggest that the main transport pathway runs via the inter tropical convergence zone, across the tropical tropopause and then to higher latitudes, i.e. into the LMS. NOx from aircraft emissions at mid-latitudes are unlikely to perturb the LMS since they are washed-out while still in the troposphere. In contrast, NOx from tropical lightning has the chance to accumulate in the LMS. Because of the longer residence times of NOx in the LMS, compared to the upper troposphere, this excess NOx from lightning has the potential to form ozone in the LMS, which then is transported back to the troposphere at mid-latitudes. In the models, around 10% of the ozone concentration and 50% of the NOx concentration in the northern hemisphere LMS is produced by lightning NOx At least 5% of the ozone concentration and 35% the NOx concentration at 150 hPa at mid-latitudes originates from tropical lightning in the climate-chemistry simulations.     

Tropospheric sources of NOx: lightning and biology.

Laboratory experiments to quantify the global production of NOx (NO + NO2) in the troposphere due to atmospheric lightning and biogenic activity in soil are presented. These laboratory experiments, as well as other studies, suggest that the global production of NOx by lightning probably ranges between 2 and 20 MT(N)y-1 of NO and is strongly dependent on the total energy deposited by lightning, a quantity not well-known. In our laboratory experiments, nitrifying micro-organisms is soil were found to be a significant source of both NO and nitrous oxide (N2O). The measured production ratio of NO to N2O averaged 2-3 for oxygen partial pressures of 0.5-10%. Extrapolating these laboratory measurements to the global scale, which is somewhat risky, suggests that nitrifying micro-organisms in soil may account for as much as 10 MT(N) y-1 of NO. Additional experiments with denitrifying micro-organisms gave an NO to N2O production ratio ranging from 2 to 4 for an oxygen partial pressure of 0.5% and a ratio of less than unity for oxygen partial pressures ranging from 1 to 20%. The production of NO and N2O, normalized with respect to micro-organism number indicates that the production of both NO and N2O by denitrifying micro-organisms is at least an order of magnitude less than production by nitrifying micro-organisms for the micro-organisms studied.     

Natural emissions for regional modeling of background ozone and particulate matter and impacts on emissions control strategies

Natural emissions adopted in current regional air quality modeling are updated to better describe natural background ozone and PM concentrations for North America. The revised natural emissions include organosulfur from the ocean, NO from lightning, sea salt, biogenic secondary organic aerosol (SOA) precursors, and pre-industrial levels of background methane. The model algorithm for SOA formation was also revised. Natural background ozone concentrations increase by up to 4 ppb in annual average over the southeastern US and Gulf of Mexico due to added NO from lightning while the revised biogenic emissions produced less ozone in the central and western US. Natural PM_2.5 concentrations generally increased with the revised natural emissions. Future year (2018) simulations were conducted for several anthropogenic emission reduction scenarios to assess the impact of the revised natural emissions on anthropogenic emission control strategies. Overall, the revised natural emissions did not significantly alter the ozone responses to the emissions reductions in 2018. With revised natural emissions, ozone concentrations were slightly less sensitive to reducing NOx in the southeastern US than with the current natural emissions due to higher NO from lightning. The revised natural emissions have little impact on modeled PM_2.5 responses to anthropogenic emission reductions. However, there are substantial uncertainties in current representations of natural sources in air quality models and we recommend that further study is needed to refine these representations.     

Modelling NOx from lightning and its impact on global chemical fields

We have used a three-dimensional off-line chemical transport model (CTM) to assess the impact of lightning emissions in the free troposphere both on NO_x itself and on other chemical species such as O₃ and OH. We have investigated these effects using two lightning emission scenarios. In the first, lightning emissions are coupled in space and time to the convective cloud top height calculated every 6 h by the CTM's moist convection scheme. In the second, lightning emissions are calculated as a constant, monthly mean field. The model's performance against observed profiles of NO_x and O₃ in the Atlantic and Pacific ocean improves significantly when lightning emissions are included. With the inclusion of these emissions, the CTM produces a significant increase in the NO_x concentrations in the upper troposphere, where the NO_x lifetime is long, and a smaller increase in the lower free troposphere, where the surface NO_x sources dominate. These changes cause a significant increase in the O₃ production in the upper troposphere and hence higher calculated O₃ there. The model indicates that lightning emissions cause local increases of over 50 parts per 10¹² by volume (pptv) in NO_x, 200 pptv in HNO₃ and 20 parts per 10⁹ by volume (ppbv) (>40%) in O₃. In addition, a smaller increase of O₃ in the lower troposphere occurs due to an increase in the downward transport of O₃. The O₃ change is accompanied by an increase in OH which is more pronounced in the upper troposphere with a corresponding reduction in CO. The method of emission employed in the model does not appear to have a significant effect globally. In the upper troposphere (above about 300 hPa) NO_x concentrations are generally lower with monthly mean emissions, because of the de-coupling of emissions from the model's convection scheme, which vents NO_x aloft more efficiently in the coupled scheme. Below the local convective outflow altitude, NO_x concentrations are larger when using the monthly mean emissions than when coupled to the convection scheme, because the more dilute emissions, and nighttime emissions, lead to a slower NO_x destruction rate. Only minor changes are predicted in the monthly average fields of O₃ if we emit lightning as a monthly constant field. However, the method of emission becomes important when we make a direct comparison of model results with time varying data. These differences should be taken into account when a direct comparison of O₃ with measurements collected at particular times and locations is attempted.     

Origin and variability of upper tropospheric nitrogen oxides and ozone at northern mid-latitudes

Year-long measurements of NO_x and ozone performed during the NOXAR project are compared to results from the ECHAM4.L39(DLR)/CHEM (E39/C) and GISS coupled chemistry–climate models. The measurements were taken on flights between Europe and the eastern United States and between Europe and the Far East in the latitude range 40–65°N. Our comparison concentrates on the upper troposphere and reveals strong longitudinal variations in seasonal mean NO_x of more than 200 pptv, which both models are able to reproduce qualitatively. Vertical profiles show maximum NO_x values 2–3 km below the tropopause (“E-shape”) with a strong seasonal cycle. E39/C simulates a maximum located at the tropopause and with a reasonable seasonal cycle. The GISS model reproduces the seasonal cycle but not the profile's shape due to its coarser vertical resolution. A comparison of NO_x frequency distributions reveals that both models are capable of reproducing the observed variability, except that E39/C shows no very high NO_x mixing ratios.Both models show that lightning and surface NO_x emissions contribute the most to the seasonal cycle of NO_x at tropopause altitudes. The impact of lightning in the upper troposphere does not vary strongly with altitude, whereas the impact of surface emissions decreases with altitude. Among all sources, lightning contributes the most to the variability of NO_x in the upper troposphere in northern mid-latitudes during summer.     

The variability of free tropospheric ozone over Beltsville,Maryland (39N, 77W) in the summers 2004–2007

Ozone profiles are often used to investigate day-to-day and year-to-year variability in origins of free tropospheric ozone. With this in mind, more than 50 ozonesonde launches were conducted in Beltsville, MD, during the summers of 2004 through 2007. Budgets of free tropospheric ozone were calculated for each ozone profile in the four summers using a laminar identification (LID) method and unusual episodes were analyzed with respect to meteorological variables. The laminar method showed that stratosphere-to-troposphere transport (ST) accounted for greater than 50% of the free tropospheric ozone column on 17% of days sampled, a more pronounced influence than regional convective and lightning (RCL) sources. The ST origins were confirmed with trajectories, and tracers (water vapor and potential vorticity). The amount of free tropospheric ozone from ST and RCL sources varied from year-to-year (up to 13%) and can be explained by differences in mean meteorological patterns. On average, almost 30% of the free tropospheric column was attributed to ST influence, about twice as much as RCL, although the LID method may not capture weeks-old lightning influences as in a chemical model. The prevalence of ST ozone in summertime Beltsville soundings was similar to six sounding sites in the IONS-04 campaign [Thompson, A.M., et al., 2007b. Intercontinental Transport Experiment Ozonesonde Network Study (IONS, 2004): 1. Summertime upper tropospheric/lower stratosphere ozone over northeastern North America. J. Geophys. Res. 112, D12S12; Thompson, A.M., et al., 2007c. Intercontinental Transport Experiment Ozonesonde Network Study (IONS, 2004): 2. Tropospheric ozone budgets and variability over northeastern North America. J. Geophys. Res. 112, D12S13.] and to statistics from a 30 year climatology of European soundings [Collette, A., Ancellet, G., 2005. Impact of vertical transport processes on the tropospheric ozone layering above Europe. Part II: Climatological analysis of the past 30 years. Atmos. Environ. 39, 5423–5435]. The Beltsville record also demonstrated the value of soundings for air quality forecasting in an urban area. The 22 nighttime soundings collected over Beltsville in 2004–2007 can be divided into distinct polluted and unpolluted subsets, the former 20 ppbv higher in residual layer ozone (1 km) than the latter. These distinctions propagated to daytime differences of 10 ppbv at the surface in the Washington, DC, area, with the high-ozone residual layers leading to non-attainment of the National Ambient Air Quality Standard for ozone. More frequent ozone observations aloft appear essential for better understanding ozone variability and for enabling air quality modelers to achieve more accurate ozone forecasts.     

In-field measurements of PCDD/F emissions from domestic heating appliances for solid fuels

Within this project the emissions into the atmosphere of polychlorinated dibenzo-p-dioxins and -furans (PCDD/F) of 30 domestic heating appliances in Austrian households were tested. The appliances were single stoves (kitchen stove, continuous burning stove and tiled stove) and central heating boilers for solid fuels up to a nominal heat input of 50 kW. A main objective of this survey was to determine the PCDD/F emissions of domestic heating units under routine conditions. Therefore, the habitual combustion conditions used by the operators were not influenced. The original fuels and lightning supports were used and the operation of the units was carried out by the householders according to their usual practice. The data obtained were used to calculate in-field PCDD/F-emission factors. Most of the appliances have shown PCDD/F emissions within a concentration range of 0.01-0.3 ng TEQ/MJ. Modern fan-assisted wood heating boilers with afterburning and units for continuously burning of wood chips and wood pellets had the lowest emissions. High emissions were caused by unsuitable heating habits such as combustion of wastes and inappropriate operation of the appliances. There were only small differences between single stoves and central heating boilers or between wood and coal-fired appliances. The emission factors calculated are higher than those cited in literature, which are mainly derived from trials on test stands under laboratory conditions.     

Variation of nitric oxide concentration before the Kobe earthquake,Japan

The variation and spatial distribution of the atmospheric concentration of nitric oxide (NO) near the epicenter of the Kobe earthquake at local time 5:46, 17 January 1995 have been studied using data at monitoring stations of the local environmental protection agencies. The concentration of NO 8 days before the earthquake was 199 ppb, about ten times larger than the average peak level of 19 ppb, accompanying the retrospectively reported precursory earthquake lightning, increase of radon concentration in well water and of the counts of electromagnetic (EM) signals. The reported thunderstorm over the Japan Sea about 150 km away was too far for the thunder-generated NO to reach the epicenter area. The concentration of NO was also found to have increased before other major earthquakes (Magnitude>5.0) in Japan. Atmospheric discharges by electric charges or EM waves before earthquakes may have generated NO. However, the generation of NO by human activities of fuel combustion soon after holidays is enormously high every year, which makes it difficult to clearly link the increase with the earthquakes. The increase soon after the earthquake due to traffic jams is clear. The concentration of NO should be monitored at a several sites away from human activities as background data of natural variation and to study its generation at a seismic area before a large earthquake.