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List of Abstracts 168LABS is unique because its location and altitude can enhance the global network of GAW (GlobalAtmosphere Watch) in the Southeast Asian region where no high-elevation baseline station is available. Oursite is located between the GAW Waliguan station (3,810 m) in Tibetian plateau and Mauna LaoObservatory (3,397m) in Hawaii. Trajectory study indicates that this site provides us a great of opportunityto observe a variety of air masses originated from source regions, giving a distinctive contrast of atmosphericchanges. Present continuous operations include precipitation chemistry, aerosol chemistry, trace gases (CO,CO2, O3, CFCs, NOy), mercury, atmospheric radiation, and meteorological variables. Mission orientedmeasurements of HCFCs, HFCs, and VOCs were also performed on a needed basis, mainly to helpdeconvolute long range transport phenomena from local circulation. Till present time, the averageconcentrations of CO, O3 and PM10 are about 121 ppb, 34 ppb and 10 microgram m-3, respectively. Theaverage pH value of precipitation is 5.73 with the major ions of SO42-, NO3- and NH4+. The averageconcentrations of mercury such as GEM, RGM and PHg are about 1.78 ng m-3, 41.7 pg m-3 and 9.0 pg m-3,respectively. The average aerosol optical depth is 0.101. The background concentrations of CO, O3 andPM10 are estimated to be about µ82 ppb, 28 ppb and 6 microgram m-3, respectively. About 32 % of thedays in a year can be categorized as polluted, which mainly occurred in March, and the concentrations ofabove three pollutants could elevate to as high as twice their background values. To summarize the results,the maximum concentration of pollutants generally occurred during spring time, especially in March,corresponding to the biomass burning from SE Asia. The LABS is also one of US/NOAA CCGG networkand NASA AeroNet. Relevant data will be presented.P-Observations 2.11 ID:4360 10:30Trace Species over the Central Himalayan and Indo-Gangetic Plain Regions: Contribution ofRegional Pollution and Long-range TransportManish Naja 1 , N. Ojha 1 , R. Kumar 1 , T. Sarangi 1 , H. Joshi 1 , P. Pant 1 , K.P. Singh 2 , Y. Kant 3 , S.Venkatramani 4 , S. Lal 41 ARIES, Nainital, India2 GBPUA&T, Pantnagar, India3 IIRS, Dehradun, India4 PRL, Ahmedabad, IndiaContact: manish@aries.res.inSatellite based observations and model results show that the northern India is the most polluted region inIndia. In view of this, for the first time, observations of various trace gases (O3, NO-NOy, CO, SO2, CO2and Hydrocarbons), aerosols (AOD, black carbon, aerosol number concentration and chemical composition)and meteorological parameters are initiated at a high altitude site (Nainital, 29.4N, 79.5E, 1958m) in thecentral Himalayas. Surface ozone and black carbon observations are also made at two other low altitude sites(Pantnagar, 29.0N, 79.5E, 231m; Dehradun, 30.3N, 78.1E, 640m) in the Indo-Gangetic regions.Observations at Nainital are representative of regional environment in the Northern Indian subcontinent andare also useful to study influences of long-range transport. Observations at Pantnagar and Dehradun are usedfor studying sources of regional pollution.Observations of ozone, NO-NOy and CO suggest that daytime net ozone production is not dominating overNainital. While other two sites show daytime higher ozone typical of urban/rural sites. In contrast to thediurnal variations, seasonal variations are more-or-less similar at these three sites with a spring maxima andsummer/monsoon minima. Seasonal variations in trace species over this region are different than those overthe western India. Based on residence time of air masses, net ozone production over Northern IndianSubcontinent in regionally-polluted air masses is estimated to be ~3 ppbv/day in spring but no clear build-upis seen in other months. Background ozone levels are estimated to be 30-35 ppbv and contribution of long-iCACGP-IGAC 2010 14 July, 2010