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A hygienic survey of the environment of underground space and buildings.

Full utilization of underground space and buildings could have positive economic and social effects. However, the microclimate and air quality must be well controlled so that they are not harmful to human health. This survey indicated that relative humidity is a common hygienic problem in underground space and buildings. Attention should be paid to humidity control and to the strengthening of routine ventilation at the construction stage. Carbon dioxide can be used as a hygiene index of air pollution: the sanitary standard for it in the air of underground buildings is 10%. The hygienic survey shows that the concentration of carbon dioxide is usually below this standard in the environments of underground space and buildings.