amonia

Michael Holliday ac017 at FreeNet.Carleton.CA
Sun Feb 22 07:42:16 EST 1998


"R Williams" (force4 at onlink.net) writes:
> what are unsafe levels of amonia indoors and when could you tell when levels
> are unsafe
> 
> Richard
> 
> 

Estimated LC values for human exposure to ammonia:


Exposure (minutes)      LC50 (ppm)      LC10 (ppm)

     120                 3,700           1,900
      60                 5,300           2,600
      30                 7,500           3,800
      10                13,000           6,600
       5                19,000           9,400
       2                30,000          15,000

Give or take factors of two or so.

DISCLAIMER (which appeared in the source identified below):  It 
cannot be emphasized enough that these dose-lethality values are 
based on few data and considerable speculation -- they should be 
used predictively only with appropriate circumspection.

Source:  Engelhardt, F.R. and Holliday, M.G., "Dose-lethality
         Relationships of Acute Exposure to Anhydrous Ammonia",
         Report No. INFO-0153.  Ottawa, Ont.: Atomic Energy
         Control Board (1 March 1985).


And, if memory serves, the ACGIH TLV(R) is 25 ppm.



The odour threshold is of the order of 10 ppm and, I am assured on 
good authority, concentrations above 400 or 500 ppm cause 
noticeable discomfort in the genital area (especially if one is 
hot and sweaty :-).  Of all mammals, bats seem the most resistant 
to ammonia and appear to tolerate atmospheric concentrations of 3000 
to 5000 ppm without adverse effects.



Michael Holliday
Ottawa, CANADA




More information about the Toxicol mailing list