[LinkLink]

Okay so 4 ferns would do it in 250 +- 100 hours then. I'm not saying one home garden will solve global co2 buildup I'm saying its significantly cheaper and potentially more rewarding as a hobby than trying to play god with air quality and a 1k budget. You're also not accounting for gaseous exchange rates related as a function to current air quality. Yes a terrible PPM is 2000 but your body produces less co2 as a result of reduced function in such an environment, therefore increasing the effect of any filtration.

[JohnBooty]

The bottom line is that you need thousands of plants to offset the CO2 exhaled by a single person. From what I can tell the ppm estimates on that page you linked are pretty generous -- they seem to be talking about the plants affecting the CO2 ppm in a very very small environment.

     I'm saying its significantly cheaper and potentially more 
     rewarding as a hobby than trying to play god with air quality 
     and a 1k budget

I don't think I agree with this dichotomy. It's like saying reading books is more fun than playing the guitar. You can do both! They're not really in conflict!

And anyway, you can do a lot with indoor air quality for 1K.