A53C-1336
Analysis of injection heights of boreal forest fire plumes determined from MISR data
Case studies show incidences in which emissions from boreal forest fires are injected into the atmosphere well above the boundary layer. We and others have shown that a significant fraction of emissions from boreal fires must be injected above the boundary layer if atmospheric concentrations of CO, ozone, and aerosols are to be simulated accurately. At present, the extent to which boreal forest fire plumes are sufficiently energetic to reach the free troposphere is not known. Our present work seeks to quantify the injection heights during a boreal forest burning season and to relate them to meteorological conditions. The multi-angle capability of the MISR instrument, aboard the NASA Terra satellite, allows us to determine the height of biomass burning plumes. We have analyzed over 600 plumes identified in Alaska and the Yukon Territories between June and September of 2004 using the MISRTOOL program. Many of these plumes were observed above the planetary boundary layer. We show that the heights of the plumes are highly correlated with levels of atmospheric stability. We have developed an algorithm for use in global atmospheric models that allows the injection heights of boreal forest fire emissions to be calculated using local atmospheric stability profiles.
A53C-1337
Improved temporal constraints on and vertical injections of biomass burning emissions: Implications on global aerosol simulation
Biomass burning from wild fires is a major source of air pollutants including aerosols and some other climate forcing agents. Biomass burning emissions are typically prescribed on a monthly base in most global chemistry and transport models (CTMs). We investigated the sensitivity of global aerosol transport and distribution to the diurnal cycle, synoptic variability, and vertical injection height of biomass burning emissions. Global simulations of aerosols were conducted using the GEOS-Chem global 3-D chemistry and transport model for summer 2004, with the aforementioned constraints imposed on the 8-day Global Fire Emissions Database (GFED v2). The diurnal cycle was determined using active fire data. The synoptic variability, which depends on temperature, relative humidity, and wind speed, was derived from a fire model. The injection height was derived from MISR smoke plume stereoheights. Model results, with monthly or 8-day (with or without the additional constraints) biomass burning emissions, were compared with aerosol optical depths (AOD) from MISR/MODIS/OMI and the AERONET network, and (mass) concentrations from the IMPROVE network and the INTEX-NA aircraft campaign. Using 8-day instead of monthly biomass burning emissions significantly improves the comparison of mass concentrations of BC, OC, and sulfate with observations. The inclusion of diurnal cycle, synoptic variability, and vertical injection height in the 8-day biomass burning emission inventory lead to more efficient transport of aerosols out of the boundary layer, resulting in lower aerosol loadings over the biomass burning source regions and higher loadings downwind, compared with simulations with monthly inventory. The inclusion of the additional constraints also reduces the discrepancies, both in magnitude and daily variability, between observed and simulated aerosol optical depths (AODs), especially downwind of the biomass burning source regions.
A53C-1338
Regional Air Pollution Impacts of Biomass Fires: Sensitivity to Uncertainties in Fuel Consumption and Fire Plume Dynamics
Biomass fires emit large amounts of trace gases and aerosols and these emissions are believed to significantly influence the chemical composition of the atmosphere and the Earth's climate system. The air quality impact of biomass burning depends on meteorology, fire plume dynamics, biomass (fuel) consumed, the quantity and chemical composition of the emissions, and the atmosphere into which the emissions are dispersed. We examine the sensitivity of model predicted CO, PM2.5, and O3 concentration fields to uncertainties in fuel consumption and fire plume dynamics, focusing on the peak of the western United States wildfire season in late August, 2006. MODIS data for fire locations and burned areas, a vegetation map for the type of biomass burned, and an extensive emission factor database are combined with different models of fuel loading (FOFEM, FCCS) and fuel consumption (FOFEM, CONSUME) to derive a four member ensemble of hourly mass emission rates for 30 gas phase and aerosol species with spatial resolution of 1-km2. Uncertainties in fire plume dynamics are represented using two different plume rise models (Briggs, PLUMP) to prescribe the vertical distribution of fire emissions, yielding eight unique emission scenarios. The air quality impact of the fire emissions scenarios is assessed by assimilating the fire emissions, along with anthropogenic and biogenic emissions, into the WRF/Chem v2.2. model, which is run using a 22-km horizontal resolution CONUS domain.
A53C-1339
The Sources and Transport of South American Dust
South America is regarded as a principal source for the dust deposited in the Southern Ocean and Antarctica, but there are conflicting modeling and observational evidences of the dust activity in this region. We use the new MODIS Deep Blue retrievals of aerosol properties over land, implemented by observations from other satellites, to identify the locations, the natural and anthropogenic origin, the local land and meteorological characteristics, and evaluate the relative importance of these dust sources in South America. Specific dust events originating from South America are recognized and the dust plumes are tracked by using a combination of ground measurement, satellite observations, and model analysis to see how far dust can be transported into the Southern Ocean and Antarctica.
A53C-1340
Does the Madden-Julian Oscillation Influence Aerosol Variability?
We investigate the modulation of aerosols by the Madden-Julian Oscillation (MJO) using satellite-based global aerosol products, including aerosol index (AI) from the Total Ozone Mapping Spectrometer (TOMS) on Nimbus-7, and aerosol optical thickness (AOT) from the Moderate Resolution Imaging Spectroradiometer (MODIS) on Terra and Aqua and the Advanced Very High Resolution Radiometer (AVHRR) on NOAA satellites. A composite analysis is performed for boreal winter, and the global pentad rainfall data from the NOAA Climate Prediction Center (CPC) Merged Analysis of Precipitation (CMAP) are used to identify MJO events. The MJO composites exhibit large variations in the TOMS AI and MODIS/AVHRR AOT over the equatorial Indian and western Pacific Oceans where MJO convection is active, as well as the tropical Africa and Atlantic Ocean where MJO convection is relatively weak but the background aerosol level is relatively high. A strong inverse linear relationship between the TOMS AI and rainfall anomalies, but a weaker, less coherent positive correlation between the MODIS/AVHRR AOT and rainfall anomalies, were found. The Aerosol Robotic Network AOT pattern at Kaashidoo (73.5°E, 4.9°N) and Nauru (167°E, 0.5°S) is more consistent with MODIS and AVHRR. These results indicate a connection between the MJO, its associated rainfall and circulation variability, and the observed aerosol variations. Several physical and non-physical factors that may contribute to the observed aerosol-rainfall relationship, such as aerosol humidification effect, wet deposition, surface wind speed, phytoplankton, different sensor sensitivities (absorbing versus non-absorbing aerosols and upper versus lower tropospheric aerosols), sampling issue, and cloud contamination, are discussed. However, a clear causal explanation for the observed patterns remains elusive. Further investigation is needed to unravel this complex aerosol-rainfall relationship.
A53C-1341
Lidar Aerosol Profiles Measured From Halifax During Summer 2007
Measurements of aerosol profiles in the troposphere and lower stratosphere were obtained with a high-power Raman Lidar from Halifax, Nova Scotia (44.63N, 63.58W) on the East Coast of Canada during Summer 2007. Observations throughout the troposphere at high temporal resolution were made possible by using a new dual-receiver setup. The lidar was operated in clear-sky conditions, and several long duration (> 80 hours) data sets were obtained. The measurements reveal the presence of boundary-layer aerosols during episodes of pollution transport from the Eastern US and Canada, and are compared with surface measurements of ozone and other species. Boundary layer development, entrainment and mixing are evident in the data. Structured plumes at higher altitudes are traced back to biomass burning events throughout North America. Aerosols were also observed on two occasions at 15 km in altitude, and are most likely due to pyroconvection. The measurements are being used to help understand transport and mixing processes, and to form a climatology of aerosol export from North America during the summer months.
A53C-1342
Revisiting "the Tropospheric Middle Eastern Ozone Maximum" With Satellite Observations of Tropospheric Ozone
Previous modelling and observational studies suggest the existence of a seasonal buildup in tropospheric ozone over the Middle East (Li et al. 2001 and Kar et al. 2002, Geophysical Research Letters). It has been suggested that this Middles Eastern ozone maximum is due to large-scale subsidence of ozone that is originally generated in the outflow of the Asian summer monsoon and transported to the Middle East by strong upper tropospheric jets. We present a detailed analysis of the seasonal cycle of ozone over the Middle East region, using recent observations from the Tropospheric Emission Spectrometer (TES) on the NASA EOS Aura satellite and the GEOS-Chem chemical transport model, to isolate the influence of photochemical production and transport on the ozone budget in the region. In general, in response to the Asian monsoon heating in the middle and upper troposphere, there is widespread descent across North Africa, the Middle East and Central Asia, and the observed seasonal accumulation of ozone reflects the influence of these centers of descent. The TES data show enhanced ozone extending from North Africa to Central Asia, while the modeled ozone abundance is at a maximum over the Middle East, reflecting possible biases in the model transport over North Africa and the Middle East.
A53C-1343
Convective Outflow From the U.S. to the Upper Troposphere Over the North Atlantic During the NASA INTEX-NA Airborne Campaign
A case study of rapid convective outflow from the U.S. was conducted using airborne measurements from flight 13 (July 28, 2004) of the NASA DC-8 during the Intercontinental Chemical Transport ExperimentNorth America (INTEX-NA). In the upper troposphere over the North Atlantic mixing ratios of CO and CH4 were elevated up to 134 and 1843 ppbv. In contrast, CO2 and OCS were reduced to 372.4 ppmv and 411 pptv respectively in the same flight regions. Overall, three regions at 8 - 11 km altitude were found to be impacted significantly by urban and industrial emissions. Here, we found good linear relationships between combustion related species such as CO, C2H2, and i-C5H12, with the urban/industrial tracers C2Cl4 and CHCl3. Moreover, the low mixing ratios and excellent correlation of OCS and CO2 indicated a signature of terrestrial uptake and minimal dilution of boundary layer air during rapid transport to the upper troposphere. Meteorological analysis, kinematic backward trajectories, and photochemical aging estimates using C3H8/C2H6 all pointed to the boundary layer over the southeastern U.S. as the source region. Halon-1211 mixing ratios exhibited no correlation or enhancement in the upper troposphere, suggesting a minimal contribution of Asian sources, in contrast to findings on other INTEX-NA flights. Our analysis indicates that convective activity over the southeastern U.S. was associated with a stationary front and strong winds ahead of the trough. The trajectories indicated that the air masses influencing the three regions meandered over the southeastern U.S. for several days prior to July 27. The air masses arriving in all three study regions were then transported over the Northeast and upward in fast zonal flow between the middle and upper troposphere on July 27-28. Moreover, flight regions sampled outside the three impacted regions also showed an excellent linear relationship between CO and CH4 and other urban tracers. This is a surprising result considering the diverse source regions indicated by our trajectory analysis. It appears that the entire tropospheric column over the North Atlantic during the time period surrounding flight 13 was impacted by North American anthropogenic emissions. Our analysis suggests that the troposphere over the mid-latitude North Atlantic basin was fumigated with U.S. pollutants in various stages of aging and demonstrates a pervasive impact of U.S. anthropogenic emissions on the mid-latitude troposphere over the North Atlantic.
A53C-1344
Identifying Convective Transport of Carbon Monoxide Through the Intercomparison of Remote Sensing Observations and Cloud Modeling Simulations
Anthropogenic pollution impacts many of the Earth's natural processes. Therefore, understanding the mechanisms that transport pollutants from the surface to the free atmosphere is important for understanding the chemical composition of the atmosphere. This study quantifies the vertical transport of lower tropospheric carbon monoxide (CO) by deep convection associated with mesoscale convective systems. Three squall line simulations (C1-C3) based on different environmental wind shear profiles are made using the 2-D Goddard Cumulus Ensemble Model, each providing post-convection profiles. Then, the Tropospheric Emission Spectrometer (TES) instrument's ability to resolve the convectively modified CO distribution is analyzed during one of the cases (C3) using a "clear sky" retrieval scheme. Results show that environmental wind shear not only impacts the structure of squall lines, but also their transport characteristics. The squall line simulation with the strongest low-level vertical wind shear is found to transport the greatest net mass of CO, with an amount of 13,421 metric tons in the low levels and 43,916 metric tons in the middle levels of the atmosphere. However, the storm with the weakest low-level vertical wind shear and weakest environmental winds aloft has a greater mass of CO transported by the updraft and the downdraft than either of the other storms. The study finds that stronger environmental winds in the upper troposphere play an important role in the propagation speeds of the squall line, which in turn impacts the horizontal distribution of convectively lofted CO. Results also show that TES has sufficient sensitivity to resolve convectively lofted CO, as long as the retrieval scene is cloud-free. TES swaths that are located downwind of squall lines are found to have the greatest chance of sensing convective transport because the impact of clouds on retrieval quality becomes less of an issue further from the squall line.
A53C-1345
Tropospheric Ozone Production from Lightning
As part of the INTEX Ozonesonde Network 2006 Study (IONS-06) ozonesondes were launched from a network of 22 stations stretching from Mexico to Canada in August and September of 2006. Vertical profiles of ozone, temperature and relative humidity were measured up to altitudes that usually exceeded 30 km. The ozone profiles from four of these stations, Barbados, Mexico City, the Ron Brown and Houston, have been evaluated with respect to lightning events that take place upwind of the profiles. The lightning is measured with the World Wide Lightning Location (WWLL) Global Network.The ozone profiles at each location were averaged over the entire measurement period and the standard deviations calculated as a function of altitude. Deviations from the averages, for each station, were calculated for the individual sounding and divided by the standard deviation to provide vertical profiles of ozone anomalies.Eighteen hour back trajectories were calculated using the NOAA HYSPLIT program to determine the history of the air mass that arrived at 10 different altitudes through which the individual sondes passed. At each hour in a back trajectory, the location was compared with the lightning frequency data base for that day and the number of lightning events, if any, was determined. Anomalies in ozone of greater than one standard deviation from the average are compared to the number of lightning events upwind and their distance from the location of the ozone measurements. A clear, positive correlation is seen between positive ozone anomalies and the frequency of lightning events.
A53C-1346
GEM-AQ, an On-line Global Multiscale Chemical Weather System: Model Description and Evaluation of Gas Phase Chemistry Processes
Tropospheric chemistry and air quality processes were implemented on-line in the Global Environmental Multiscale model. The integrated model, GEM-AQ, has been developed as a platform to investigate chemical weather at scales from global to urban. On the global scale, the model was exercised for five years (2001-2005) to evaluate its ability to simulate seasonal variations and regional distributions of trace gases such as ozone, nitrogen dioxide and carbon monoxide. The model results are compared with observations from satellites, aircraft measurement campaigns and balloon sondes. The same model has also been evaluated on the regional (~15km resolution) and urban scale (~3km resolution). A simulation of the formation and transport of photooxidants during the European heat wave of 2006 was performed and compared with surface observations throughout central and eastern Europe. The complex topographic region of the Lower Fraser Valley in British Columbia was the focus of another model evaluation during the PACIFIC 2001 field campaign. Comparison of model results with observations during this period will be shown.
A53C-1347
The Relationship Between Tropospheric OzoneAnd Atmospheric Circulation Over Taiwan
The influence of long-range transport on increasing tropospheric ozone pollutions in Taiwan was identified by using an objective weather type classification scheme and spatial compositing analysis during the 1994-2004 period. The results of weather type classification show that the occurrence of high ozone pollution episodes is especially associated with the anticyclone type, the anticyclonic easterly type and the north-easterly. The features of these three specific weather types suggest that high ozone pollution episodes over Taiwan were affected by long-range pollutant transport due to the inflows from China, Korea and Japan accompany with high ozone concentrations. The results of spatial compositing analysis also prove the mechanism of long-range transport is related to the large-scale atmospheric circulation. During spring and autumn period, extension of the Siberia High over China accumulates pollutants both from rural and industrial areas, and along the eastern border substantial ozone precursors and pollutants from the area of divergence and northern industrial areas can be transported downward to Taiwan. This suggests that the change of atmospheric circulation, which is caused by global warming, could influence tropospheric ozone pollution over Taiwan, or even East Asia region, in the future, as this pressure pattern is associated with the changes in the monsoon circulation.
A53C-1348
The role of atmospheric transport in controlling mercury concentrations in wet deposition over the northeastern United States
The regional influence of large coal-combustion mercury sources on mercury concentrations in wet deposition in the northeastern United States is investigated. Mercury concentrations in weekly precipitation samples were obtained from four National Atmospheric Deposition Program (NADP) sites: Millford, PA (PA72), Huntington, NY (NY20), Bridgton, ME (ME02), and Freeport, ME (ME96). Mean volume weighted mercury concentration at PA72 from 2001-2006 stands out as being about 25% higher (7.6 ng/L) than the other sites which showed equivalent mercury concentrations (6 ng/L). Much of increase in mercury concentration at PA72 appears to occur in the spring months (March-May), when the volume-weighted mean concentration (10.0 ng/L) is nearly 60% higher than what is observed for the sites in New England (~6.3 ng/L). We find that these differences are largely due to the unique location of PA72 relative to the major northeast U.S. outflow pathway. The dependence of mercury concentrations on transport pathway is quantitatively determined by calculating how much time each precipitating air mass has spent in a pre-defined emissions region using ensembles of HYSPLIT back trajectories for the years 2004-2005. By totaling the number of trajectory hours that have positions inside this source region over the same period of time as a weekly mercury sample, a parameter called "trajectory residence time" is generated. Our results indicate that during the spring at PA72, trajectory residence time can explain about 60% of the variability in the weekly mercury concentration. This relationship is much weaker at sites further to the north and east. A comparison of the transport pathways between the six highest and lowest mercury concentration weekly samples at PA72 reveals important seasonal changes that have a strong influence over peak and baseline mercury concentrations. Our results allow us to estimate over what spatial scales the origins of mercury sources are most likely: winter is a mix of global and regional, spring is almost entirely regional, summer is a mix of regional and local, and fall is almost all local. Spring and summer are when emissions from the coal- combustion source area have the most influence on mercury in precipitation at PA72. Because of this, we find that there is a significant downward trend in the spring and summer months (0.9 ng/L/year, P<0.001, N=6), while the fall and winter months show no trend. This suggests that further emissions reductions during the spring and summer would have a proportionally larger effect of lowering mercury in wet deposition at PA72 than emissions reductions at other times of the year.
A53C-1349
Is the stratosphere an important source of reactive mercury in the free troposphere?
Mercury is a significant environmental concern and there remain large uncertainties in its global atmospheric cycling. Gaseous elemental mercury (GEM) is relatively unreactive and is therefore the dominant form in the free- troposphere. Ozone and OH are believed to be the primary oxidants that transform GEM to reactive gaseous mercury (RGM) which can then be readily dry and wet deposited which is the primary removal pathway of atmospheric mercury. The ozone and OH oxidation mechanisms, however, have recently been challenged on thermodynamic grounds. Since 2005, we have measured GEM and RGM at the Mt Bachelor Observatory (2.7 km. asl) in Central Oregon. Significant enhancements in RGM are frequently observed in dry, free tropospheric air masses (Swartzendruber et al., 2006). The enhancements could not be linked to recent anthropogenic emissions, but rather were correlated to air with a stratospheric or upper-tropospheric character. We have continued to research the mechanisms controlling speciation in the free-troposphere through observations at MBO in 2006 and 2007, and an aircraft study in 2006. The three years of MBO data and the aircraft data have been analyzed with respect to meteorology and the enhancements appear to be linked to synoptic-scale subsidence and tropopause folds. Chemical relationships during RGM enhancements are generally consistent with an upper-troposphere or stratospheric source, with a few exceptions. The chemical relationships suggest that in the stratosphere, mercury is primarily in the oxidized form. If this inference is correct, the flux of RGM from the stratosphere can be estimated from the ozone-RGM slope. This flux is nearly the same or greater than the supposed in situ oxidation by ozone. As the chemical form of the observed RGM remains unknown and the direct oxidation of elemental mercury by ozone and OH has recently challenged on a thermodynamic basis, stratospheric input could be a significant source in the tropospheric budget. Hence, the evolution of the specific oxidation mechanisms operating in the lower stratosphere may affect the RGM concentrations in the free troposphere and ultimately deposition to the surface.
A53C-1350
Measurements of Atmospheric Mercury at a High Elevation Site (Lulin Atmospheric Background Station, LABS) in Taiwan
Taiwan is located on the edge of the west Pacific Ocean and to the downwind side of East Asia, which is the largest anthropogenic mercury (Hg) emitting region globally. It has been demonstrated that the environmental quality of Taiwan can be influenced by regional Asian atmospheric pollution events, such as acid deposition, dust storm, and biomass burning. Therefore, Taiwan could also be under the influence of the East Asian Hg emissions. As a result, continuous atmospheric Hg measurements have been conducted at Lulin Atmospheric Background Station (LABS, 2862 m a.s.l.) since April 13, 2006 to study the long-range transport and transformation of atmospheric Hg. Three types of atmospheric Hg, including gaseous elemental Hg (GEM), reactive gaseous Hg (RGM), and particulate Hg (PHg), are measured using the Tekran 2537A/1130/1135 speciation system. Here we report the atmospheric Hg data collected between April, 2006 and April, 2007. The average GEM, RGM, and PHg concentrations were 1.83(±0.65) ng m-3, 17.85(±18.70) pg m- 3, and 6.12(±7.36) pg m-3, respectively. Seasonal variability in GEM concentration was evident with higher GEM concentrations between fall and spring. The highest monthly GEM average of 2.43 ng m-3 was observed in October, 2006. GEM concentrations were usually low in summer months with the lowest monthly average of 1.10 ng m-3 in July, 2006. Backward trajectory analysis indicated change in air mass origins among seasons. In summer (May ~ July), air masses were mainly from the Pacific Ocean with minimal land influence. On the other hand, between fall and spring, air masses were more or less under the influence of East Asia continent. These results suggested that Taiwan could be impacted by East Asia Hg emissions between fall and spring. Also, spikes of RGM were frequently detected between midnight and early morning with concurrent decreases in GEM and relative humidity and increases in ozone concentrations, suggesting the oxidation of GEM and formation of RGM in free troposphere.
A53C-1351
Mixing of continental and marine air masses and en route chemical transformations in transPacific transport of aerosols: Lagrangian analysis of a single transport event.
Observations and model studies in the Western Pacific region report evolving aerosol size distributions and heterogeneous chemical transformation of Asian aerosols. Recent papers report sea salt mixing and acid- carbonate reactions in single particle analyses of Asian dust when sampled in Korea and Japan. Model studies indicate similar processes en route from Asia to North America, but direct observations of aerosol transformations in transit from Asia to North America have been lacking. Simultaneous operation of time-, size-, and elemental composition- resolving aerosol samplers in Korea and California captured both ends of a transPacific transport event in April, 2002 during the Intercontinental Transport and Chemical Transformation experiment (ITCT-2K2). These data permit direct observation of the interaction of Asian continental air with the Western Pacific marine boundary layer, as well as evaluation of the evolution of aerosol size distributions and chemical composition in transit over the North Pacific. Our results resolve questions about the mechanisms of mixing of continental and marine aerosols, help clarify the source regions of the Asian aerosols, and also show systematic, qualitative differences between processes in the Western and Eastern Pacific that explain apparent contradictions between the Korea/Japan shoreline data with observations from North America. In addition, such near and far field data can be used to validate transPacific aerosol transport modeling without need for accurate emission data.
A53C-1352
Trans-Pacific Transport of Ozone and Reactive Nitrogen in Spring
We interpret observations from the Intercontinental Chemical Transport Experiment, Phase B (INTEX-B) in spring 2006 using a global chemical transport model (GEOS-Chem) to evaluate sensitivities of the Pacific and North American free troposphere to Asian anthropogenic emissions. Satellite observations of tropospheric NO2 columns provide timely information on trends in Asian NOx emissions over 2003-2006 (8.1% yr-1). We examine ozone and reactive nitrogen measurements from three aircraft platforms from the INTEX-B campaign, including a Canadian Cessna taking vertical profiles of ozone near Whistler Peak. Our baseline simulation reproduces measured ozone and reactive nitrogen profiles with small biases (7% for ozone, 20% for NOx, and 13% for peroxyacyl nitrates (PN's)). Asian anthropogenic emissions have a mean contribution of > 6.9 ppbv to simulated ozone profiles; lightning NOx emissions contribute > 3.6 ppbv to ozone profiles on average. Tropospheric ozone columns from the Ozone Monitoring Instrument (OMI) exhibit a broad Asian outflow plume across the Pacific, which is reproduced by simulation. Mean modelled sensitivities of Pacific tropospheric ozone columns to Asian anthropogenic emissions and lightning are > 3.7 Dobson Units (DU) and > 2.1 DU. A sensitivity study decoupling PN's from the model's chemical mechanism establishes that PN's contribute up to 4 ppbv to surface springtime ozone concentrations in western Canada. While ozone production due to PN transport is greatest in the eastern Pacific, persistent winds advect this ozone northeastward into Canada. Transport events observed by the aircraft confirm that airmasses with enhanced PN's (> 500 pptv), ozone (> 95 ppbv), and CO (> 150 ppbv) were advected in this way.
A53C-1353
Source-Receptor Relationships for East Asian Sulfur Dioxide Emissions and Northern Hemisphere Sulfate Concentrations
We analyze the effect of varying East Asian (EA) sulfur emissions on sulfate concentrations in the northern hemisphere based on a global coupled oxidant-aerosol model (MOZART-2) driven with NCEP reanalysis meteorology for 1991. We conduct a base and several sensitivity simulations, in which sulfur emissions from each continent are tagged, to establish the source-receptor (S-R) relationship between EA sulfur emissions and sulfate concentrations over the source and downwind regions. We find that reducing EA SO2 emissions will significantly decrease the spatial extent of the EA sulfate influence over the North Pacific, but raising EA SO2 emissions will not significantly increase the spatial extent of influence. We define a linearity index and find the S-R relationship between EA SO2 emissions and EA sulfate concentrations to be nearly linear over most downwind regions, but to be non-linear over the EA source region, particularly at the surface and in winter. In addition, we find that besides the direct transport of EA sulfate to North America (NA) and Europe (EU), the indirect response of locally-produced NA or EU sulfate to changes in EA SO2 emissions is negative (i.e., offsetting the direct effect) in winter, spring and fall, but becomes positive in summer. In summer the indirect response is as important as direct transport of EA sulfate over the southeastern U.S. and southern EU. This summertime positive indirect effect largely results from induced changes in H2O2 oxidant concentrations over these regions.
A53C-1354
Long-range transport of polycyclic aromatic hydrocarbons (PAHs) from the eastern Asian continent to Kanazawa, Japan with Asian dust
Aerosol particles were collected for 1 year, starting in April 2003, in rural areas of Kanazawa, Ishikawa, Japan to understand the role of Asian dust as a long-range transporter of polycyclic aromatic hydrocarbons (PAHs). Three sampling intervals were designated in this study, namely: (1) Dust period 1 (March 1119, 2003); (2) Dust period 2 (March 28, 2003April 9, 2003); and (3) Dust period 3 (April 9, 2004April 25, 2004). The Asian dust particles are predominantly in the coarse particle size range (2.111 m). PAH analyses were performed separately on both the coarse and fine (<1.1 m) particle ranges. Seasonal trends in PAH concentrations for coarse and fine particles showed that the Asian dust particles in Dust period 3 contained significant amounts of less-volatile PAHs such as benzo[a]pyrene (BaP) and benzo[g,h,i]perylene (BghiP). A kinetic model developed in this study shows that almost none of these PAHs would be accumulated on Asian dust particles in the atmosphere, due to their extremely slow adsorption rates. These PAHs would have to originate from PAH-polluted soil particles around industrialized areas. Back trajectory analyses suggest that the Asian dust in Dust period 3 came from loess regions around industrialized areas. This indicates that geologic materials play a significant role in the atmospheric circulation of PAHs.
A53C-1355
Exceptional Air Pollution Events: Regional and Intercontinental Dust and Smoke
The national air quality standards for PM2.5 and ozone provide for the exclusion of data for a given day when it is strongly influenced by "exceptional events" (EE), such as smoke from wildfires or windblown dust. In order to apply for EE exclusion, states must provide appropriate documentation to support the dominance of uncontrollable sources on that day. Most of EE days are due to regional or continental-scale smoke and dust events. Here we report the candidate methodologies that are being developed for the quantification and documentation of EE over the US, including: (1) Observed/modeled pollutant transport based on trajectory and regional models; (2) Spatial pattern of pollutant derived from surface (AIRNOW, FRM, Visibility) and satellite data (TOMS, GOES, AVHRR, SEAWiFS, MODIS); (3) Temporal pattern analysis; (4) Chemical fingerprinting and source apportionment. The characteristics and initial climatology of EE over the US will also be be presented.
A53C-1356
Intercomparison of transpacific transport of Asian pollution between global and coupled global-regional model simulations
The Intercontinental transport and Climatic effects of Air Pollutants (ICAP) project supported by the U.S. EPA was launched in 2001 to enhance our understanding on transpacific Asian pollution and to improve the ability of models to quantify its influences in the United States. We participate in this work using a 3-D global chemical transport model (GEOS-Chem) which also provides dynamic chemical boundary conditions for hemispheric scale simulations by regional air quality model (CMAQ). Our focus is mainly on Asian O3 and sulfate aerosol which are two dominant Asian pollutants in the United States. We conduct a model inter-comparison of GEOS- Chem and CMAQ, and also evaluate them using observations from the Transport and Chemical Evolution over the Pacific (TRACE-P) aircraft campaign over the western Pacific to examine important processes for Asian pollution transport. O3 and sulfate aerosol concentrations in the United States due to Asian pollution are simulated quite differently between two models despite consistent anthropogenic emissions over East Asia. CMAQ shows lower O3 but much higher sulfate aerosol concentrations in the United States relative to those of GEOS-Chem. A simple transport difference between two models cannot explain this issue. Compared with TRACE-P observations CMAQ shows lower O3 over the western Pacific due to missing processes such as stratospheric O3 influx and lightning NOx which are typically absent from regional air quality models, whereas sulfate aerosol concentration in CMAQ is higher than both observations and GEOS-Chem because of aqueous- phase chemistry and wet scavenging mainly driven by meteorological data. Our analysis indicates that proper simulations of meteorological processes such as warm-conveyor belt and deep convection are crucial for simulating transpacific transport of Asian pollution.
A53C-1357
North American Pollutant Export and Associated Ozone Radiative Forcing During the Summers of 2002 and 2004
The anthropogenic contribution to North American pollutant export and ozone radiative forcing is evaluated for the summers of 2002 and 2004. The evaluation is performed using the University of Maryland Chemistry and Transport Model (UMD-CTM) driven by GEOS-4 CERES reanalysis data. The goals of the simulations are to quantify North American pollutant outflow and to estimate the effects of this outflow on the forcing of climate by tropospheric ozone. Simulations are performed with and without North American anthropogenic emissions. Year-specific biomass burning emissions are used. As the first part of this evaluation, model output is compared to satellite-(MOPITT CO and SCIAMACHY NO2), aircraft-(UMD RAMMPP O3, NASA DC-8 and NOAA P-3), and ground-based measurements (AIRMAP, CASTNET, NOAA CMDL), and to output from simulations with the Global Modeling Initiative (GMI) CTM. Export and import fluxes of NOx and NOy are calculated. As the second part of this evaluation, the radiative forcing due to the additional ozone production by North American anthropogenic emissions was calculated. Clear sky infrared forcing approaching 1 Watt per square meter was seen over portions of the eastern United States and the western Atlantic during some pollution episodes. Smaller values of this forcing were seen throughout Europe and northern Africa. We compare the magnitudes of the North American pollutant export and radiative forcing between the 2002 Summer season (more polluted along the US east coast) and the cleaner Summer of 2004.
A53C-1358
A new Isotope Tracer to Identify Long Range Transport and Transformation of Aerosol
It is of interest to understand the intercontinental transport of dust particles because they can accumulate anthropogenic nitrate, sulphate and carbonaceous compounds (black carbon and aromatic hydrocarbon) on their surfaces by adsorption during transportation. Carbonate is a prominent component of the soils in north western China where much of the Asian dust is produced. Carbonate can affect atmospheric chemical processes and aerosol characteristics because the acid neutralizing capacity of this species facilitates the heterogeneous conversion of sulphate and nitrate The primary goal of this work is to develop an isotope methodology for carbonates that can be used as a chemical marker for the origin of polluted air plumes. The results will be compared with other established tracers such as nitrate and sulphate that possess anomalous oxygen isotopic composition in polluted environments from reaction with ozone. Aerosol samples were collected on filter papers using Anderson Cascade Impactors at two different locations in La Jolla, California: one at the Scripps Pier and the other one at coastal Mount Soledad (800 ft). The particulate samples were allowed to react with excess H3PO4 at 28 oC for 14h and the gaseous compounds released were collected at liquid nitrogen. CO2 gas was separated from other reaction products by gas chromatography. In order to measure the oxygen isotope composition, CO2 gas was fluorinated to release oxygen gas to be analysed on the isotope ratio mass spectrometer. We discuss the carbon and oxygen isotope composition of the CO2 released from the fine (< 1 um) and coarse (> 1um) particles collected at two different sites (Mt. Soledad and Scripps Pier) and its utility as a tracer to identify the long range transport of aerosol from local pollution events. The secondary organic oxidation products and concomitant isotope may provide a new indicator of chemical transformation. The transport situation of the air parcels will be analyzed through back trajectory analysis from sampling sites based on National Oceanic and Atmospheric Administration (NOAA) data (http://www.noaa.gov/).
A53C-1359
Chemical Transformation of CaCO3 Particles by Heterogeneous Reaction with HNO3: Kinetic Measurements over a Wide Range of Humidity
Mineral dust aerosol comprises one of the largest mass fractions of the total global aerosol loading. As mineral dust aerosol is entrained and transported through the atmosphere, it can undergo heterogeneous reactions with trace atmospheric gases, which alter the chemical balance of the atmosphere. Meanwhile, changes the particle chemical composition and surface properties also occur, and in this way affect the impact of the particle on climate through direct and indirect radiative forcing. The importance of heterogeneous interactions between mineral dust and reactive trace gases on a global scale has been demonstrated by several modeling studies. A number of field studies have shown that particles containing solid calcium carbonate (CaCO3) undergo complete, irreversible processing by heterogeneous reaction with gaseous nitric acid (HNO3) to form highly hygroscopic Ca(NO3)2. Such conversion of insoluble material to soluble material strongly affects the hygroscopic properties of mineral dust particles, as well as their ability to serve as cloud condensation nuclei. Uptake of HNO3 on mineral dust is one of the most important, but least certain parameters in the analysis of the impact of dust on tropospheric ozone concentrations. To assess this impact, accurate measurements of the heterogeneous uptake coefficient (γ) under conditions representative of the atmosphere are critical. In the present work, we investigate the heterogeneous reaction of gaseous HNO3 with CaCO3 particles using a novel technique that utilizes exposure of substrate deposited, isolated, and narrowly dispersed particles to a gas mixture of HNO3/H2O/N2, followed by microanalysis of individual particles. Chemical transformation of micron size CaCO3 particles by heterogeneous interaction with HNO3 concentrations of 7- 25 ppb, similar to those found in a polluted atmosphere, and reactive uptake over a wide relative humidity range are reported. The net reaction probability (γnet) was found to increase with an increase in the relative humidity, from 0.003 at RH = 10% to 0.21 at 80%.
A53C-1360
Regional Air Pollutions in Three Different Regions of Asia From a Transcontinental Transport Perspective
Asia is known as one of the regions with the fastest rate of growing in industrialization and urbanization. As a result, the rapid increases of large-scale air pollution in Asia emerge as a serious concern at both domestic and international levels. Apart from the problems of air quality degradation, emission control, environmental risk, and health effect in a domestic level, evidences from scientific studies indicate that by the long-range transport, Asian air pollution is becoming a global problem. Observations and model studies confirm that air pollution from Asia could be transported to North America or farther. In this work, we investigate the Asian air pollutions, in particular ozone and some other atmospheric components such as carbon monoxide and black carbon, from the ground- based observations in the three different regions, namely 1) background region of Siberia and central Asia, 2) highly anthropogenic region in eastern China, and 3) the rim region of the Asia-Pacific. In a transcontinental transport perspective, these regions are regarded as the inflow region, source region, and outflow region of Asia, respectively. From the results, it is found that the influences from large-scale emission in East Asia are observed clearly in the source region, and to the significant extent in the outflow region. For the inflow region of Asia, our data in Siberia and Kyrgyzstan indicate that air masses in this region are mostly intact from large-scale anthropogenic emission, and remain much of the global background atmospheric pollution characteristic. When the air masses are transported to source region, the air pollutants level increased sharply and frequent episodes of extremely high pollutions have been observed. Our results show good correlation between the residence time of air masses over the source region in eastern China and the observed levels of air pollutants verifying the strong enhancements by anthropogenic emissions from industrialization and urbanization. In the outflow region, air pollutants characteristics depend largely on the air mass climatology. In most cases, increases of air pollutants level are observed with the transport events directly from the source region.
A53C-1361
The formation mechanism of heavy haze over China
Most cities in China have been suffering from very heavy haze, a new weather pattern, which formed for more than one third of the whole year in the past several years. High concentration of fine aerosol, much frequent occurrence plus rapid formation were the three main characteristics of the heavy haze. As a typical example, the air pollution in an inland city, Urumqi, located in the center of Asia, was systematically monitoring and investigated for the past 6 years. 19 elements and 16 ions were measured in PM2.5 and TSP aerosols collected over urban Urumqi, as well as those surface soil samples collected from inside the city, the surrounding areas, and those upstream areas of Asia dust. With comparison of the pollution elements abundance in aerosol/soil and using Ca/Al as a tracer, it was identified that the mixing of the local anthropogenic aerosol with the transported soil dust from outside the city was the main sources of the high concentration of sulfate, which was the one of the main factors causing the heavy air pollution in the aerosols over the urban area. The industrial emitted sulfur dioxide was converted to sulfate in the aerosol and the soil dust containing high concentration of sulfate from the agriculture field located in the south of Jungger Basin and Salt Lake areas was transported to the air over the city. The total water soluble ions (TWSI) and the total ammonium salts were as high as 57.8% and 51.0% in PM2.5. The extremely high concentration of TWSI, especially the high concentration of ammonium salts with very high hygroscopicity, plus the low wind speed could be the main factors, to form the heavy haze over China.
A53C-1362
Trends, Distribution and Frequency Analyses of Ozone Data From Three Monitoring Stations in Baton Rouge, Louisiana for the Years 1995 to 2005
Troposphere ozone concentrations exhibit pronounced, characteristic diurnal and seasonal cycles. These cycles are usually well-defined. However, additional oscillations can also occur; these are generally much smaller in amplitude than the 1-day or 1-year cycles and they might be attributable to anthropogenic influences (e.g., specific man-induced meteorological and chemical influences on an individual monitoring station, periodic maintenance activities, etc). Indeed, it is possible that the spectral analysis of photochemical pollution data could pinpoint hidden conditions that affect particular monitoring stations. Such an analysis, one based on Fourier transform methods, was applied to long-term data from 3 American monitoring stations. As would be expected, strong signals were found for the 1-day and 1-year periods; however, some weaker signals, ones probably associable with anthropogenic affairs, were also observed. A principal component analysis (PCA) was applied to the transformed data sets in order to identify these periods and make pollution ranking. Periods of 0.5, 3.5-days and 7-days, as well as a number of other cycles, were found and can be considered to be markers of anthropogenic influences. European and American data will be compared and the effects of Hurricane Katrina will be examined.
A53C-1363
Four Summers of Ozone Profiles Over Beltsville, MD: A Study of Free-Tropospheric and Boundary Layer Ozone
A total of over 75 ozonesonde launches were made in Beltsville, MD during the summers of 2004 through 2007 as part of 4 different field campaigns; INTEX Ozonesonde Network Study 2004 (IONS-04, http://croc.gsfc.nasa.gov/intex/ions.html), Howard/NCAS ozonesondes for MDE (Maryland Department of the Environment) Pollution Episodes (http://www.physics1.howard.edu), and the Water Vapor Validation Experiment Satellite/Sondes 2006 & 2007 (WAVES, http://ecotronics.com/lidar-misc/WAVES.htm). These profiles were used to characterize variability in sources of tropospheric ozone. On average, free-tropospheric ozone was composed of the following: 10% regional convection and lightning-derived NO, 25% stratospheric ozone, with the balance (~65%) a mixture of aged air of indeterminate origin and recently advected ozone. A separate analysis of local emission and boundary layer ozone was performed. The data from 2005 and 2006 includes both nighttime and daytime launches, permitting an investigation between planetary boundary layer processes and surface ozone. In nighttime profiles with above average column ozone in the residual layer, daily maximum 1 hr and 8 hr average surface ozone values were roughly 10 to 15 ppbv greater than days with below average column ozone in the residual layer. These results, as well as vertical profiles, were compared to the NOAA/EPA Operational Air Quality Model forecasts for Beltsville. The model showed a highly negative bias for maximum 1 hr ozone values, but only a slightly negative bias for maximum 8 hr ozone values on days with above average residual layer ozone.
A53C-1364
Characteristics of aerosols in east Asian outflow at Cheju in spring
Measurements of aerosols and traces gases were conducted at Gosan site (33o17fN, 126o10fE) on Cheju Island, South Korea from 17 March to 6 April 2005. In the spring season, outflows of pollutants from east Asian continents are associated with high pressure system centered over northern region of China and Mongolia. Measurements were continuous for carbonaceous aerosols (BC, OC and WSOC), PM2.5 inorganic aerosols, and trace gases. To investigate dominate source region and transport pathway of air parcels 5-day isentropic back trajectories at 950 hPa were calculated. Based on these trajectories air masses were classified in five contrastingly different categories as (1) Maritime (11%), (2) Free tropospheric (34%), (3) Yellow Sea (16%), (4) Korean (8%), and (5) Chinese (31%). Temporal variations of aerosols and trace gases track each other, in particular for species primarily emitted by anthropogenic activities. All species were observed to show large variability due to alteration in the episodes of air masses from different categories. Mean (} SD) mass concentrations of BC, OC, WSOC and SO42- were 1.18}0.83, 4.2}1.6, 1.26}1.01 and 4.0}3.4 ƒÊg m-3, respectively. Concentrations of carbonaceous and PM2.5 aerosols, which are emitted by anthropogenic activities, show lowest in maritime and highest in Chinese plume. The mean concentrations of BC, OC, WSOC and SO42- in Chinese plume were 1.9}0.92, 5.5}1.3, 2.0}1.1 and 6.7}4.1 ƒÊg m-3, respectively. The observed slope E#162;BC/E#162;CO =9.2 (ng m-3/ppbv) will be compared with emission inventory data over China. K+ shows good correlations with SO42- and NO3- signifying role of combustion related process like biomass burning.
A53C-1365
Construction and analysis of an ozone profile climateology over Houston, Texas
Since the summer of 2004, over 200 ozonesondes have been launched from the campuses of Rice University or the University of Houston (29.7 N, 95.3 W), each about 3 miles from downtown Houston. These sounding launches have been sponsored by NASA, the Shell Center for Sustainability of Rice University, and the Texas Commissions for Environmental Quality as part of a large effort to understand Houston's ozone problem. Data from these soundings have provided valuable insight into the seasonal and diurnal variations of the vertical ozone distribution and their relationship to changes in atmospheric conditions. In this presentation, we show annual and seasonal variability in the ozone profile, evidence for the impact of meteorological factors on the ozone profile, and comparisons of the ozonesonde data with TES and OMI retrievals. http://www.rice.edu/ozone
A53C-1366
Observations of Hydrogen Peroxide (H2O2) and Methylhydroperoxide (CH3OOH) at Mt. Bachelor Observatory During the Spring-Summer 2007
Observations of hydrogen peroxide (H2O2) and methylhydroperoxide (CH3OOH) were made at Mt. Bachelor Observatory (MBO), Oregon, during the summer 2007. H2O2 and CH3OOH, primary HOx precursors, were measured in order to constrain the sources and sinks of mercury. Prior to constraining mercury observations, the relationship between peroxide levels and meteorological measurements at MBO were investigated. Ambient peroxides were collected using continuous flow glass scrubbing coils, then analyzed with enzyme fluorescence techniques. Prior to analysis, H2O2 was separated from organic peroxides using High Performance Liquid Chromatography with a C-18 column. Preliminary results show peroxide variability is linked to diurnal, wind direction, and local air quality changes. Local fires were present during the later portion of the intensive study and allowed extensive sampling of peroxides during biomass burning events.
A53C-1367
Search for Ozone Plumes over Western Long Island Sound, NY, CT
A search has been conducted for near-surface ozone plumes extending roughly northeastward from New York City, by employing ozonesondes carried by a boat on western Long Island Sound. This water-borne search pattern avoids the local sources densely distributed on land in the suburban counties and small cities in Westchester, Long Island, and Connecticut. The observations are done using ECC 2Z ozonesondes and Vaisala 80-15 radiosondes normally used for ozone profiles in the troposphere and stratosphere. The sensors were placed forward on the boat, to avoid ozone produced by the boat's own engine. Several straight traverses were made between the north and south shores. These were extended into bays and harbors where it was possible without much bending of the trajectory, in order to lengthen the runs and carry them close to shore. These runs proceeded (somewhat diagonally, zig-zagging) from west to east, followed by a straight 30 mile direct radial transit approaching New York City southwestward. The data has been examined to look for aligned peaks on the transverse runs at the various radial distances from New York City, which would indicate the existence of ozone plumes transported northeastward from the city. Concentration variation in the radial direction was also examined. The study is expected to be extended to eastern Long Island Sound and the New York bight, south of Long Island
A53C-1368
Characteristic variation of PM10 in Seoul, South Korea during 2000-2005
PM10 along with O3, CO, SO2 and NO2 has been monitored at 13 stations in Seoul, the capital of South Korea. During 2000-2005, annual PM10 mean concentrations were increased until 2002 and then decreased. While Asian dust events were the most frequent in 2001, in 2002, the highest concentrations of PM10 were recorded nationwide. The effect of Asian dust on PM10 is evident in monthly variations, in which PM10 concentrations were the highest in March and April. Except these two months, the second maximum PM10 was found in June, when O3 levels in exceedance of National Air Quality Standards were the most frequently observed. PM10 concentration was the lowest in August, which is mainly due to heavy rains during summer monsoon. Particularly, monthly PM10 concentrations were very well correlated with the frequency of westerly wind. On the other hand, the percentage of easterly wind was negatively correlated with PM10, leading to the lowest concentration in August and September. These temporal distributions of PM10 will be fully understand to implement policy for PM10 abatement in Seoul. http://atmos.korea.ac.kr
A53C-1369
Modeling the impacts of convective transport and lightning NOx production over North America: Dependence on cumulus parameterizations
A 3-D regional chemical transport model (REAM) is applied to examine the uncertainties in modeling the effects of convective transport and lightning NOx production on upper tropospheric O3 and its precursors. To assess the model uncertainties, two different cumulus convective parameterizations, KF-eta and Grell, are adopted in REAM from the respective meteorological models, WRF and MM5. The model simulations are evaluated using INTEX- NA aircraft measurements. A major improvement of the KF-eta scheme (in WRF) is its inclusion of entrainment and detrainment processes. It simulates larger convective updraft mass fluxes below 300 hpa than the Grell scheme (in MM5), resulting in better simulations of vertical profiles of the concentrations of CO, C3H8, and C4H10 in the middle and upper troposphere. More efficient scavenging from entrainment and detrainment also results in better simulations of highly soluble pollutant HNO3 in the free troposphere in WRF-REAM. The inclusion of entrainment and detrainment processes in the KF-eta scheme also leads to lower cloud top heights (10-12 km in WRF) than the Grell scheme (13-16 km in MM5) and hence smaller amounts of estimated intra- cloud lightning flashes. WRF simulated cloud top heights are in better agreement with GOES satellites measurements over the southeastern United States and the Atlantic Ocean. The WRF-REAM model better simulates lightning NOx distributions than the MM5-REAM, especially over the Atlantic Ocean. Lightning NOx production enhances the concentration of upper tropospheric NO2 by a factor of > 2 (~50 pptv) and increases O3 by up to 20 ppbv.
A53C-1370
Air mass back trajectory analysis for air quality in Anmyeon Island, Korea
Air mass back trajectory analysis was assimilated with data of greenhouse gases (CO2, CH4, CFCs), reactive gases(O3, CO, NOX and SO2) and PM10. The data continuously measured in real time at KGAWC from Jan 2006 to Jul 2007. KGAWC (Korea Global Atmosphere Watch Center) is one of regional stations of WMO/GAW and located in Anmyeon Island, the western coast of Korea peninsula (32° 32'N, 126°19'E). Usually we can see the backward trajectory to know how to inflow from the source of atmospheric gases. In our study, we categorized inflow direction focused on Anmyeon Island. New attempt was made to continuous tracking air mass with measurement time series. Data of back trajectories was achieved from HYSPLIT web site. The directions of trajectories were separated to five areas centered at the station; North China including Mongol, South China, North Korea around Sea of Okhotsk, South Korea and the Pacific, northern east sector include Seoul metropolitan in domestic (local area). The trajectories were presented in five different colors by the areas with 120 hours backward in Y-axis and 3-hour interval time series in X-axis. With the trajectories, the measurements results could classify to Asian dust, long-range transported air pollution and clean air cases. The peaks of PM10, CO, SO2 were related to the cold front from China. Other peaks were due to inflow from the Metropolitan and industrial area in Korea. Because the life time of NOX is short compared with other gases, NOX is not affected from China. However, high concentration of NOX was shown with inflow from the Metropolitan and industrial area in Korea. Surface O3 was simultaneously decreased to the increase of NOX concentration by the reaction NO + O3->NO2 + O2. The peaks of CO2, CH4, CFC-11 were observed with NOX peak. Low peaks of SO2 from the Metropolitan inflow are due to the Regulation of air pollution in Korea.