Impact of the respiration of ornamental flowers on the composition of the atmosphere in hospital wards

Ornamental flowers were sampled in hospital wards and their respiration rates measured. We calulated the maximum possible contribution of the flowers to the CO₂ and O₂ content of the ward air, during an eight hour night. Only 1.6% of the CO₂ increment in the ward air during the night (estimated to increase under most unfavourable conditions from 0.03 to 0.37% v.v.) was estimated to result from the presence of the flowers. The depletion of oxygen due to the flowers was calculated to be likewise negligible. Actual measurements of CO₂ in the ward air in the early hours of the morning showed CO₂ concentrations below 0.1%. It is concluded that nightly removal of ornamental flowers is not justified by their effect on the composition of the ward atmosphere.