## Introduction: Ozone Simulator

simulOzone is an open app for PC and smartphone that allows you to view the trend of ozone concentration in air and water.

It is a simulator, therefore it simplifies the reality it represents, e.g. considers an instantaneous and homogeneous distribution of ozone in the volume to be treated, but it clearly displays the reduction that is obtained using the PDM, the trend of concentration overtime, the limit levels.

It is true that experience is a great teacher, but an instrument of this type I believe is fruitful in the first steps of using an ozone generator or at least it helps not to make big mistakes and to get a better understanding of the factors at stake.

## Step 1: The Problem

The sanitization with Ozone of apartments and houses is very common against the coronavirus. But The problem is: how? how long? This project can help.

The concentration of ozone in a given volume depends on two factors:

1. Amount of Ozone generated in the unit of time (mg/h or g/h). This is a characteristic of the generator used, but may vary due to the decrease in efficiency of the generator over time, or due to the presence of high humidity in the air, the lack of oxygen, etc ...
2. Ozone consumed per unit of time, proportionally to the concentration. It is assessed with a parameter, half-life, equal to the time required to halve the concentration present (Ozone in the air: from 20 min to a few hours; in water, from seconds to minutes). The main mecha­nism is the self-recombination of ozone in oxygen but many factors intervene

• temperature, movement of the ozonated fluid, air humidity,
• ozonated air escaping from the treated environment, etc ...
• presence of substances with catalytic effect,

Since there are a production and a consumption mechanism at the same time, the ozone concentra­tion tends to an equilibrium value that cannot be overcome. In other words, for each combination of genera­tor/environment there is a limit to the maximum concentration that can be obtained, even keeping the generator ON for a very long times.

This constitutes the problem: the concentration is defined by differential equations and follows an exponential trend; therefore it is a non-linear quantity and cannot be evaluated with simple mathe­matical operations.

## Step 2: A Solution

But it can be calculated with appropriate tools!

This is the motivation that pushed me to create simulOzone, an ozone concentration simulator.

It shows the trend of the ozone concentration in a given volume
(room or container, air or water), with a first phase in which the gen­erator is active and a second in which the concentration decreases up to a safety value (50 - 200 ppb), showing if enough concentration is reached (e.g. 20 minutes @2000 ppb).

• It calculates the maximum concentration reached (in ppm) and the total time [min] to return to safety conditions.
• The graph is expandable on the time axis up to a maximum of 6000 minutes (over 4 days).
• It is easy to use, a setup page allows the user to enter the main options once and this simplifies the two main pages.
• It can be used on PC (Win, Linux, OS), on tablets, and smart­phones (Android).
• It is open: you can change it to experiment, or to adapt it to your needs.
• For the mathematical analysis of the model used, see info on Malthus law.

An instrument of this type I believe is fruitful in the first steps of using an ozone generator or at least it helps not to make big mistakes and to get a better understanding of the factors at stake.

It is available in English and Italian from here: https://github.com/msillano/Ozone-coronavirus-sonoff/tree/master/PROJECTS-DIY/simulOzone

The full story (wit use and install instructions) can also ben downloaded directly: