Does the type of gas i put in affect the time to have the gas engine running in order to meet the emission standard?

Maybe I have a totally wrong concept: The lower the gas, the "dirtier" the gas will be, therefore the gas engine has to run longer in order to meet the low emission standard. Thus, the EV mode will not kick in as early as I am using higher type (89) gas?

I used to use type, i just changed to 87 and I realize that the EV mode kicks in at the later stage. I am confident that my driving habbit is the same though.

What do you think?

Doubt it very much. 87 octane is no 'dirtier' (whatever that means) than higher octane. The higher the octane the more resistant a fuel is to detonation. High compression engines can cause the fuel to detonate before the spark. Using higher octane in these engines allows the fuel to not detonate until the spark causes it. Using high octane fuel in an engine that does not require it does nothing except make you spend more on gas. So save the money.

If you're finding a difference in when EV mode kicks in I'm guessing it's for some other reason.

And just to add to that... The reason high compression engines develop more power with high octane fuel, is that the computer will adjust fuel/air mix causing lower power if it detects detonation from low octane fuel (ie 87).

The TCH technically has a high compression engine if you look at the specs, but the Atkinson cycle design nullifies this in actual use by reducing how much fuel/air mix actually is in the cylinder when the spark plug fires reaping all kinds of benefits like low pollution and high mileage.

Two climate control systems, one inside and the other at the tailpipe.

2007 Camry Hybrid (in service June 2006)
FE: 6.77L/100km (34.8 mpg) over 37750km (23450mi)
75% city - Ave trip 20 min - 2 Winters