One possible source of indoor air pollution is gasoline engine of motor vehicle. High carbon monoxide (CO) concentration raises the level of CO Hb in the blood, thus causing health disruption
ranging from headache to death. One of the efforts which can be applied to cope the problem is
utilizing CO absorber plants such as yellow palm (Chrysalidocarpus lutescens), suji leaves
(Dracena deremensis) and ferns (Nephrolepis exaltata). The research was aimed to reveal the
ability of the three plants in reducing CO concentration, and also to know which plant has the
highest absorbing power. The study was an experiment which employed pre test-post test with
control group design, and for each type of plant, there were five replications. Motorcycle engine
used in the research as the pollution source was ignited for 30 minutes before the subsequent
exhaust gas were exposed in one hour to the experiment room which had the dimension of 3 m
length, 2 m width and 2 m height. The results showed that the decrease of CO concentration
among the three plants were 76,14 % for Chrysalidocarpus lutescens, 81,18 % for Dracaena
deremensis, and 84,08 % for Nephrolepis exaltata, and the statistical test proved that those
percentage were significantly different (p < 0,001). Further test, found that ferns (Nephrolepis
exaltata) has the highest absorbing capability.