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VOC Hydrogen Sulfide

                                                     TESTING THAT MAKE'S SENSE

Testing NELAC      PCO Testing    Testing PCO

This study was conducted by an accredited independent lab in accordance with NELAC Institute to determine the potential use of the SafeGuard Family of PCO products for the inactivation of VOC's in the air stream of a typical heating or cooling system as they might appear in the common household.  Using the strict guidelines of ASTM Standard D-5116-97 recognized by ASHRE and the EPA. 


Two of the most common organic voc's and carcinogenic were chosen in our testing Formaldehyde and Hydrogen Sulfide.   Both are carcinogenic.    


The study took place using a controlled environment in the form of a sealed cabinet with recirculating air over a period of 48 hours.  First without the PCO activated and then 48 hours with the PCO activated.

Diagram 1 shows the results of Hydrogen sulfide reduction over a 48 hour period using only air circulation and no filtration.


Bar 1    100% Concentration

Bar 2       75% Concentration

Bar 3       91% Concentration

  48 hours 91% Concentration
Diagram 2 shows the results of  reduction over a 48 hour period using air circulation and activating the AirWash PCO. 


Diagram 2 shows the results of Hydrogen sulfide reduction over a 48 hour period using air circulation and activating the AirWash PCO. 


Bar 1    100% Concentration

Bar 2    40% Concentration

Bar 3    20% Concentration

  48 hours no detection

                                                       Hydrogen Sulfide (H2S)


Hydrogen Sulfide (H2S) is a colorless gas that smells like rotten eggs (from the sulphur). Often referred to as "sewer gas," hydrogen sulfide is highly poisonous.



Usually, the poisoning caused by hydrogen sulfide is though inhalation and has a toxicity similar to cyanide. It is found in petroleum and natural gas and is sometimes present in ground water. Natural gas can contain up to 28% hydrogen sulfide gas and may be considered an air pollutant when found near a natural gas production area or refinery.

Low Levels of H2S
The odor or hydrogen sulfide gas can be perceived at levels as low as 10 ppb (parts per billion). At levels of 50-100 ppm (parts per million), it may cause the human sense of smell to fail. Low levels can cause eye irritation, dizziness, coughing, and headache.

High levels of H2S
At high exposures (usually greater than 300 ppm), H2S has the amazing effect of causing the nose to stop perceiving its smell after a few inhalations, which may lead to the inhalation of a toxic or fatal dose (which can occur at 600 ppm). At high levels, hydrogen sulfide gas may paralyze the lungs, meaning that the victim may then be unable to escape from the toxic gas without assistance.

Deaths are not uncommon when people enter poorly ventilated spaces such as deep wells, underground tanks or sewer systems. Since H2S gas is heavier than air, its concentration is highest near the bottom of enclosed spaces.


Detecting hydrogen sulfide (H2S):

Manning Safety Services, Inc. sells devices for the detection of hydrogen sulfide gasses as well as personnel gas masks.