Carbon Monoxide Levels & Risks
CO Level
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Action
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1-4 ppm
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Normal levels in human tissues produced by body.
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3-7 ppm
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14% increase in the rate of admission in hospitals of non-elderly for asthma. ( Sheppard-1999)
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5-6 ppm
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Significant risk of low birth rate if exposed during last trimester ( Ritz & Yu-1999)
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5 ppm
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9 ppm
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ASHRAE standard for allowable spillage from vented appliances, indoors, for 8 hours exposure daily. EPA standard for outdoors for 8 hours and a maximum 3 times per year. ( Clean Air Act)
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10 ppm
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Outdoor level of CO found associated with a significant increase in heart disease deaths and hospital admissions for congestive heart failure. ( JAMA, Penny) lst ambient level occupants should be notified-NCI Protocol
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15-20 ppm
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First level World Health Organization lists as causing impaired performance, decrease in exercise time and vigilance. 1st Alarm level for NSI 3000 Low Level CO Monitor-5 minutes
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25 ppm
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Maximum allowable in a Parking Garage (International Mechanical Code)
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27 ppm
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21% increase in cardio respiratory complaints (Kurt-1978)
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30 ppm
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Earliest onset of exercise-induced angina (World Health Organization). 1st visual display on UL2034 approved CO Alarm-Must not alarm before 30 days
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35 ppm
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US NIOSH recommended 8 hour maximum workplace exposure. EPA standard for outdoors for 1 hour and a maximum of 1 time per year. Many fire departments wear breathing apparatus before entering 2nd ambient level. Occupants should be notified and space ventilated. 2nd Alarm level for NSI 3000 Low Level Monitor-5 minutes
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CO Level
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Action
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50 ppm
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US OSHA recommended 8 hour maximum workplace exposure Maximum NCI level for Unvented appliances
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70 ppm
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1st Alarm level of UL2034 approved CO Alarms- 2-4 hours 3rd Alarm level for NSI 3000 – 30 seconds NSI 3000 Low Level Monitor cannot be silenced by reset button
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100 ppm
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Maximum NCI CO level during run cycle in all vented appliances(stable) Maximum NCI CO for all oil appliances
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200 ppm
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First listed level(established in 1930) healthy adults will have symptoms-headaches, nausea NIOSH & OSHA recommend evacuation of workplace Maximum “Air Free” CO for vented water heater and unvented heaters (ANSI Z21) UL approved alarms must sound between 30 – 60 minutes(NSI 3000 – 30 seconds)
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400 ppm
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Healthy adults will have headaches within 1-2 hours. Life threatening after 3 hours Maximum “Air Free” CO in all vented heating appliances (ANSI Z21) Maximum EPA levels for industrial flue exhaust UL Alarms must alarm within 15 minutes (NSI 3000 – 30 seconds) Maximum recommended light-off CO for all appliances – NCI (except oil)
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800 ppm
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Healthy adults will have nausea, dizziness, convulsions within 45 minutes. Unconscious within 2 hours then Death (established in 1930). Maximum “Air Free” CO for unvented gas ovens (ANSI Z21) 800 ppm+ Death in less than one hour
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2000 ppm
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EPA standard for new vehicle emissions
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3000 ppm+
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Typical emissions from propane lift trucks, gasoline powered tools etc. Death in less than 30 minutes.
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PPM = parts per million. A measure of pollutant concentration. Parts of pollutant per million parts of air.