Ammonia
Ammonia is a very dangerous chemical that causes many injuries and deaths annually:
When Ammonia is released into the environment, it eventually will dissipate up into the atmosphere, where it degrades into nitrogen and hydrogen. But until it does dissipate upwards, it has a great potential to harm. Under certain circumstances and concentrations, ammonia can ignite. The IDLH of ammonia is 300ppm. Ammonia has a molecular weight of 17.03 kg/kmol. Ammonia boils at -28.17 degrees Fahrenheit. The "footprint" for ammonia was modeled for day and night conditions in Phoenix, Arizona on June 2, 1999, and Portland, Maine, on January 15, 1999. The temperatures for Phoenix were 90 during the day and 68 at night; Portland's were 40 during the day and 20 at night.
The various plume models for ammonia illustrate many things.
A ten-fold increase in the amount spilled does not mean a ten-fold increase in the distance the plume will travel, but the area of the plume does increase. The warmer the ambient temperature, the faster the ammonia will dissipate upwards, limiting the distance the plume will travel. The effect of sunlight in causing this dissipation is evident by comparing the day and night "footprints." A good breeze will make for a thinner plume that does not reach the same distance as a slight breeze, partly by helping the ammonia to dissipate through mixing. The plumes of ammonia resembled each other in both locations. Ammonia is an EPCRA EHS chemical, with an RQ of 100 pounds, and a TPQ of 500 pounds. Ammonia is also a CERCLA Hazardous Substance with a CERCLA RQ of 100 pounds.
Ammonia Phoenix, AZ Urban/Rural Day 90°F and Night 68°F at 5k and 20k
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500 lbs |
5,000 lbs |
50,000 lbs |
500,000 lbs |
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5k/Urban/day 90°F |
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5k/Rural/day 90°F |
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20k/Urban/day 90°F |
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20k/Rural/day 90°F |
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5k/Urban/night 68°F |
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5k/Rural/night 68°F |
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20k/Urban/night 68°F |
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20k/Rural/night 68°F |