# Carbon oxide

Carbon Monoxide ( $CO$ ) is extremely dangerous substance to human health and life. It originates from the incomplete combustion of hydrocarbon fuels and some chemical reactions. No $CO$ should be detected in inhabited premisses at any time. Trapped in the blood flow, Carbon Monoxide reacts with blood hemoglobin. Hemoglobin which combined with $CO$ is unable to react with oxygen and transport it to the body cells.

Permissible levels of $CO$ in the indoor air is very low due to it’s toxicity.

## Regulatory levels

### Regulations for industrial environments

• OSHA
• PEL = 50 ppm (TWA) - highest average concentration for any 8-hours period
• MAK
• 30 ppm - highest average concentration for any 8-hours period
• 60 ppm - highest average concentration for any 30-min period
• GOST 12.1.005-88 Occupational safety standards system. General sanitary requirements for working zone air
• 20 $\mu g/m^3$ - highest permissible concentration
• 50 $\mu g/m^3$ - highest permissible concentration for 1-hour exposure. Not less than 2 hours prior repetitive exposure
• 100 $\mu g/m^3$ - highest permissible concentration for 30-minutes exposure. Not less than 2 hours prior repetitive exposure
• 200 $\mu g/m^3$ - highest permissible concentration for 15-minutes exposure. Not less than 2 hours prior repetitive exposure

### Outdoor air regulatory levels

• U.S. EPA
• 9 ppm - highest average concentration for any 8-hours period, not to be exceeded more than once a year
• 35 ppm - highest average concentration for any 1-hour period, not to be exceeded more than once a year
• California
• 9 ppm (10 $mg/m^3$) - highest average concentration for any 8-hours period, not to be exceeded more than once a year
• 20 ppm (23 $mg/m^3$) - highest average concentration for any 1-hour period, not to be exceeded more than once a year
• Japan
• 10 ppm - highest average concentration for any 24-hours period
• 20 ppm - highest average concentration for any 8-hours period

## Reference levels

### Reference levels for industrial environments

• NIOSH:
• REL = 35 ppm - a workplace exposure limit - *Time Weighted Average (TWA) for exposure of 8 hours/day, 40 hours/week, for a working lifetime
• 200 ppm - maximum exposure
• ACGIH
• 25 ppm - highest average concentration for any 8-hours period

### General reference levels

• ASHRAE
• 9 ppm - 8 hours exposure
• WHO:
• 90 ppm - highest average concentration for any 15-min period
• 50 ppm - highest average concentration for any 30-min period
• 25 ppm - highest average concentration for any 1-hour period
• 10 ppm - highest average concentration for any 8-hours period

• South Korea
• 10 ppm