# Carbon dioxide

Carbon Dioxide is not actually taken seriously as a pollutant. Everyone nowadays aware of Green House Effect, but very few people have understanding what does it mean. During thousands of years Carbon Dioxide content was fluctuating around 300 ppm due to natural causes. In 1950s the influence of the mankind power consumption on the atmosphere became a significant factor of climate change. The concentration of ambient $CO_2$ started to rise, caused by booming industry and transport emissions. Current concentration of Carbon Dioxide in the ambient air is 413 ppm and rising. Check CO2.earth for the trend, it’s pretty scary. Humans cant distinguish with their fillings between ambient $CO_2$ concentration from let’s say 1000 ppm. However, concentrations above 2000 ppm, which often can be experienced in premisses with poor ventilation, may reduce the mental and perception abilities despite still cant be notice be human . Drowsiness and headaches start from 10000 ppm - 12000 ppm. Breathing difficulties begin when Carbon Dioxide concentration reaches 20000 ppm (2%) $CO_2$ concentration of 30000 ppm (3%) doubles the breath rate.

Various organizations state standards for $CO_2$ concentrations if the indoor air.

## Regulatory levels

### Regulations for industrial environments

• OSHA
• 5000 ppm - highest average concentration for any 8-hours period
• PEL = 10,000 ppm (1%)
• STEL = 30,000 ppm (3%)
• MAK
• 5000 ppm - highest average concentration for any 8-hours period
• 10000 ppm - highest average concentration for any 1-hour period

### Outdoor air regulatory levels

• U.S. EPA
• 1000 ppm - for continuous exposure

## Reference levels

### Reference levels for industrial environments

• NIOSH:
• 5000 ppm - highest average concentration for any 8-hours period
• TLV = 10,000 ppm (1%) - maximum concentration of substance for 10-hours work shift at the workplace
• PEL = 30,000 ppm (3%) - highest average concentration for any 15-minutes period
• IDHL = 40,000 ppm (4%) - Immediately Dangerous to Life or Health
• ACGIH
• 5000 ppm - highest average concentration for any 8-hours period
• 30,000 ppm - highest concentration for any 15-minutes period

### General reference levels

• ASHRAE
• 1000 ppm - for continuous exposure [standards 62-1989 and 62-1999]

• South Korea
• 1000 ppm