Dr Takahashi
	See the following two references for some recent measurements of
the del O-18 values for atmospheric CO2:

	Trolier et al. (1996) J. of Geophysical Research 101: 25,897-25,916

	Flanagan et al. (1997) Global Biogeochemical Cycles 11: 83-98

Cheers,

Larry Flanagan







>Dear Isogeochemers,
>
> I tried to know CO2 absorption effects of roadside trees by
>del-13C and del-18O of CO2.
>  In my preliminary analysis, I found that del-18O of CO2 in urban air
> (near road) were 7 to 20 permil (PDB  base) in March in Japan.
>But, I dont have any data set of del-18O of CO2 in air
>Any information about del-18O of CO2would be greatly appreciated.
>Thanks,
>
>Dr. Kazushi TAKAHASHI
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