Great piece and research. Some indoor plants would help on the CO2 front and also in reducing other air pollutants.
“Dr Torpy’s research group analysed the effect of indoor plants on air quality in workplaces and found that in offices with plants, CO2 levels reduced by about 10 per cent in an air-conditioned building and 25 per cent in a building without air-conditioning.” http://www.abc.net.au/news/health/2016-03-09/how-houseplants-can-help-reduce-indoor-pollution/7230094