Going Green

I know camp fuel is suitable for indoor spinning, but whats the most environmentally- friendly fuel for outdoor? We all inevitably inhale our fuel, so I use camper fuel mostly for its benefits; virtually invisible smoke/fumes & minimal odor. On the down side the fumes are more dangerous; egniting easier requiring more attention to safety. So despite the minimal odor is it also more dangerous for the atmosphere? I'd like to mix kerosene & white fuel to achieve the benefits of both, but kerosene burns w/ black smoke & a strong smell. I like how white fuel lights quickly & enjoy making fire trails ( I prefer excess comes off as fire instead of fuel like w/ kerosene). When performing in a group camper fuel's quick burn time is alright, but I want to find a fuel to mix w/ for a longer burn (especially for practicing). Can anyone recommend a fuel besides kerosene, something with a cleaner burn, that is most environmentally- friendly while making it so I can burn longer?