ClO2- Relative Humidity in Chambers

Goal: After discussion with David S. and Joel T. the direction of altering the relative humidity inside the modified anaerobic chambers was brought up. Joel was very happy with the killing curves I was getting, but remarked that one of the biggest factors facing the actual application and use of the chlorine dioxide gas in the field is the humidity in the area. Some places are rather dry and others are very humid, so for my next series of experiments I will alter the humidity inside the chambers and then generate ClO2 inside them. The effect the gas has on the P. larvae spores will be interesting to see. Since the 200 mg total dry weight of ClO2 reagent seemed to have a large effect on the spore survival, that is the weight that will be used throughout these experiments.

I will start by getting an idea of the ppm of chlorine inside the chambers over the course of six hours at a very low relative humidity. For this, no additional water was added to the chambers which resulted in a relative humidity inside the chambers of around 30-35%.

Reading the Cl2 ppm columns

An image of what the columns look like after taking a 200 mL sample from the modified anaerobic chambers with ClO2 reagents in them. There is a green "front" in the columns as you take a gas sample.

The ppm were determined by reading the spot right at the interface between the green front and where the stronger orange color begins. This spot is illustrated by an arrow in the image above. Calipers will be used to more accurately determine the ppm.

Relative Humidity Estimates

A rough estimate of the amount of water in the air inside the chambers was determined based off of this graph.

relative humidity	g of H2O /kg air	g H2O in air/ chamber
30%	5	12.5
60%	9	22.5
90%	11	27.5

//EWW