CGEIC Global Mercury Emissions Inventory (GEIA Global Mercury Emissions Inventory, Version 1.2.)
(Note: Version 1.0 and 1.1 are obselete and should not be used)

	                                   Current Version 1.2 98/01/22        
						(Previous Update Version 1.1 97/10/01)
						(Previous Update Version 1.0 97/05/23)

This file contains information regarding the mercury data set available on the
CGEIC web site <http://www.info.ortech.on.ca/cgeic>. A description of this data
set can be found in the following reference:

        Pacyna, J.M. and Pacyna, P.E., June 1996, "Global Emissions of Mercury 
        to the Atmosphere Emissions from Anthropogenic Sources", Norweigian 
        Institute for Air Reasearch (NILU), Kjeller, Norway, DRAFT Report.

The mercury file, hg_v1_2.txt, consists of three comma delimited fields 
as follows:

        1) Grid Number
        2) Area Sources (Sum = 1641.99, Maximum Value = 21.87539)
        3) Point Sources(Sum =  501.99, Maximum Value = 17.56)

There are 10346 data records in hg_v1_2.txt.

Definition of Data Fields:
--------------------------

Field 1     Grid Number

            The GEIA grid is used, which is a 180x360 grid with 1 degree latitude
            x 1 degree longitude cells. The latitude - longitude coordinates of a 
            cell are those of the southwest corner of the grid cell. Note: Only grid
            cells which contain emissions are included in this file. Grid cell numbers
            are a packed integer representing both latitude and longitude as described
            below:
            
            Grid number= (latitude+91)*1000+(longitude+181)

            The origin, packed cell number 1001 for this grid system is located
            at the lower left edge of the grid, which corresponds to -90 degrees
            latitude, -180 degrees longitude.

            To unpack the grid number into Latitude and Longitude follow these
            steps:
            
	    1) Divide Grid Number by 1000
               example: 1003 / 1000 = 1.003 

            2) To calculate Latitude take the integer portion of the number in
               Step 1) and subtract 91.
               example: Latitude = 1 - 91 = -90 degrees latitude

            3) To calculate Longitude take the decimal portion of the number
               in Step 1) and multiply by 1000 (e.g. 1.003 = 3) and subtract 181.
               example: Longitude = 3 - 181 = -178 degrees longitude

Field 2 	Area Source Mercury Emissions
		Units=Tonnes of Mercury Per Grid Per Year

Field 3	Point Source Mercury Emissions
		Units=Tonnes of Mercury Per Grid Per Year

While not represented as a separate field, Total Mercury can be calculated as
Total Mercury = Area Source Mercury + Point Source Mercury.

(1 Tonne = 1000 kg)

Note:
-----
Point sources such as power plants, smelters and other major point sources of
mercury are assumed to have a physical stack height and a sufficiently buoyant
plume that the emissions are transported into the atmosphere above 100 m.
Since not all regional and national inventories had sufficient information to
enable a split to be made between high and low elevation sources, some grids
lack high level data and in such cases all emissions are reported in the low
level (i.e. Area Sources)field. The North American emissions of mercury have
not yet been resolved into area and point sources. This will be done in a 
future version.

Update Information:
-------------------

Version 1.2 (98/01/22)
	In previous version (Version 1.1) different countries contributing to
	the same grid had separate entries. Hence, some grids had more than one
	emission record. In current version 1.2 all countries contributing to a
	grid have been summed into that grid. Hence, there are no repeated grid
	records. Note, however, that the total emissions for the inventory have
	not changed.

Version 1.1 (97/10/01)
	The update from the previous version of the Mercury inventory 
	(version 1.0)includes a spatial redistribution of USSR emissions.


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