Health Effects of CO 2  The ratio of indoor to outdoor concentration of CO 2 is generally greater than '1'  The concentration level of CO 2 to cause any serious health problems in the range of 30,000 ppm  Respiration is effected at concentration levels from and above 15,000 ppm  Above 30,000 ppm it can cause headaches, dizziness and nausea  Prolonged exposure to concentration above 5000 ppm can increase the incidence of illness  The concentration of 5000 ppm is adopted as TLV for the submarines
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