February 8, 2011

Micromort - The grim unity of measure

For those who loved the Final Destination movies and want to put some science into it, here an original unity of measure:

A micromort is a unit of risk measuring a one-in-a-million probability of death (from micro- and mortality). Micromorts can be used to measure riskiness of various day-to-day activities. A microprobability is a one-in-a million chance of some event; thus a micromort is the microprobability of death. The micromort concept was introduced by Ronald A. Howard who pioneered the modern practice of decision analysis.

Risks that increase the annual death risk by one micromort, and their associated cause of death:

smoking 1.4 cigarettes (cancer, heart disease)
drinking 0.5 liter of wine (cirrhosis of the liver)
spending 1 hour in a coal mine (black lung disease)
spending 3 hours in a coal mine (accident)
living 2 days in New York or Boston (air pollution)
living 2 months in Denver (cancer from cosmic radiation)
living 2 months with a smoker (cancer, heart disease)
living 150 years within 20 miles (32 km) of a nuclear power plant (cancer from radiation)
drinking Miami water for 1 year (cancer from chloroform)
eating 100 charcoal-broiled steaks (cancer from benzopyrene)
eating 40 tablespoons of peanut butter (liver cancer from aflatoxin B)
travelling 6 minutes by canoe (accident)
travelling 10 miles (16 km) by bicycle (accident)
travelling 230 miles (370 km) by car (accident)
travelling 6000 miles (9656 km) by train (accident)
flying 1000 miles (1609 km) by jet (accident)
flying 6000 miles (9656 km) by jet (cancer from cosmic radiation)
receiving one chest X-ray in a good hospital (cancer from radiation)
taking 1 ecstasy tablet

Below the hit parade of the causes of death in US, interesting to see that you have more propabilities to die with an insect sting than with an earthquake, it appears we do not have to worry too much about Osama Bin Laden as well:

Micromorts per year (US)
• All causes, age 80: 80000
• Heart disease: 2519
• Stroke: 589
• Unintentional injury: 340
• Cancer: 195
• Car accident: 148
• Leukaemia: 76
• Homicide: 64.8
• Accidental poisoning: 35
• Food poisoning: 17.7
• Drowning: 15.6
• Fire: 12.1
• Killed by co-worker: 9
• Tuberculosis: 5
• Train accident: 2
• Electrocution: 1.5
• Airplane accident: 0.9
• Asteroid impact: 0.76
• Floods: 0.4
• Terrorism: 0.3
• Lightening: 0.2
• Insect sting: 0.2
• Earthquake: 0.1
• Train crash: 0.09
• Struck by fallen airplane:0.06
• Hurricane: 0.04
• Bioterrorism: 0.018
• Fireworks accident 0.01

Hang gliding involves a risk of eight micromorts per trip while Scuba diving involves five and a parachute jump (in the US) is about 17.

If you want to read more on this:

Howard, R. A. (1980). "On making life and death decisions". In J. Richard, C. Schwing, Walter A. Albers. Societal Risk Assessment: How Safe Is Safe Enough? General Motors Research Laboratories. New York: Plenum Press.
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