At night plants start to produce CO2 as well - when you're sleeping and most vulnerable! If the amount of CO2 they scrub is significant, the amount of CO2 they produce in the evening should be as well, no?
Plants produce a net deficit of CO2, so you're correct but over a 24 hour period with proper lighting they will produce more oxygen than CO2. The important thing, however, is that they produce this CO2 at night at such an unbelievably slow rate that you wont be choking to death in your sleep, that's silly. If you fill a room with plants and cut out the lights, most CO2 produced will be from your cat sleeping on the floor than from the plants.
Either way I was referring to other chemicals that plants remove from the air, not CO2.
Apparently plants put out half the CO2 again over the night that they took in. I'm just thinking that either way they aren't that big of deal as far as oxygen/carbon dioxide production/consumption. Air filtration, possibly.
Depends on the number of plants. Growing up, my mom was a florist and we had an abundance of plants throughout the house. Wouldn't necessarily suggest going to that level, but plants do make for a much less sterile environment. Big green leafy plants are better air scrubbers and much easier to care for than cute dainty flowers.
Depending on choice of pot and soil, most only need to be watered once a week. Even still, there are decorations that hold water to slow release for even extended times between watering. Great for vacations, or the forgetful.
I didnt really mean CO2 specifically, I meant it improves air quality by removing other chemicals from the air. Either way the effect is not completely insignificant especially over long periods of time with correct conditions.