On Sep 23 , at 1:00 PM, John M. Steele wrote:
The EPA will require reporting of greenhouse gas emissions beginning
2010 from major sources, which are those emitting over 25000 metric
tons (CO2 equivalent) of several listed greenhouse gases. We can
all be happy that they are using metric measure but sad that they
butcher the symbol, using "mtCO2e"
I agree that "mtCO2e" is stupid. It is stupid on two separate (and
unrelated) accounts.
(1) The symbol for metric tonnes is "t". Moreover, it is perfectly
appropriate (and more strictly SI) to report it as megagrams (Mg).
Also, several 25 thousand megagrams could (should?) be expressed in
gigagrams, thus "25 Gg".
(2) It is improper to add qualifiers to a unit. It is the measured
quantity, the emissions, that requires the qualifier, not the tonnes.
Thus, the phrase should read (making one change):
"... major sources, which are those whose CO2-equivalent emissions of
several listed greenhouse gases are over 25000 metric tons."
or (making both changes):
"... major sources, which are those whose CO2-equivalent emissions of
several listed greenhouse gases are over 25 Mg."
Bill Hooper
74 kg body mass*
Fernandina Beach, Florida, USA
* plus or minus a kilogram or so.
