Timezones

[eluser]renownedmedia[/eluser]
I've been adding the following line to my entry point of time-sensitive applications before using CI:

Code:

putenv("TZ=America/Detroit");

I'm wondering two things, the first is should I be using this line in my applications or is there a better method, and also should I stick this in the index.php of CI or is there a better location?