Ozone is a commonly used gas for sterilization in various industries for its strong oxidizing property. In its applications, ozone is most commonly used for space and surface sterilization, odor removal, water treatment, and many industrial uses. However, due to its strong oxidizing properties, to avoid its negative side effects, it’s necessary to pay attention when it is used in order to avoid its side effects. What we will do is to take advantage of its physical properties to play a positive role, while avoiding its negative effects due to its physical property. Therefore, in order to use ozone more safely, we have concluded the following precautions when ozone is used.
1. Ozone’s Effects of Human Health
Ozone is safe when its concentration is controlled. But there will he health concerns on human health if inhaled at levels above the safe line. The negative effects of ozone are mainly on the respiratory system.
On one hand, breathing in ozone can cause irritation to the throat and lungs, causing cough, asthma, breathing difficulty, chest pain and tightness, etc. Long-term exposure to ozone can cause serious damage to the respiratory system, causing inflammation and damage to the airways and making the lungs more susceptible to infection. Ozone will also worsen lung diseases such as asthma, emphysema and chronic bronchitis, etc. On the other hand, ozone can also cause eye and nose irritation. If the eyes are irritated by ozone, they need to be flushed with plenty of water immediately. If large amounts of ozone is breathed in, the person needs to be immediately transferred to a well-ventilated environment without ozone. If the breath stops, then an artificial respiration by a trained person will be urgently needed.
When an ozone generator is used in a room for sterilization or odor removal treatment, the processing time should be limited within 30 minutes. For some larger room conditions, the processing time can be appropriately extended. When an ozone generator is working in a room, there should be no person or pets in the enclosed space. After the treatment, the room should be ventilated for at least 30 minutes to ensure an adequate diffusion of the ozone gas.
2. Ozone’s Effects on Plants and Certain Items
The strong oxidizing property of ozone also affects plants and certain items. Firstly, the existence of high concentrations of ozone can cause the emergence of irregular spots on plants in the environment, which will turn the leaves red or darker, and sometimes death of the plants. Secondly, ozone can also cause the discoloration of items that contain organic pigments. Some of the items susceptible to ozone include synthetic carpets, foam mats, furniture covers, plastic products, rubber materials and products, fabric products, wire wrappers, the artworks, etc.
Therefore, in order to avoid the unwanted effects of ozone on the above items, it is necessary to move any items that may be discolored or with its color changed by ozone out of the room before the ozone treatment begins.
3. Ozone and Car Odor Removal
Ozone can be applied to remove car odors from its interior. However, the strong oxidizing property of ozone will at the same time accelerate the aging of leather and rubber materials used in the car. Therefore, when using an ozone generator for the odor removal in a car, it is recommended to use a minimum concentration, and keep the processing time no longer than 20 minutes. The advice is to scrub the interior of the car with ozone water rather than the direct use of ozone in its gas form. Also, since ozone can result in the accelerated aging of tires, ozone generators are not recommended for the use in garages.
4. Feed Gases: Natural Air vs. Oxygen
When using ozone generators for producing ozone, either natural air or oxygen can be used as feed gases.
Firstly, the main difference between the two is that when natural air is used as the feed gas for ozone generation, there will be a high flow rate of ozone, but with low concentration. While when oxygen is used as the feed gas, the flow rate will be relatively low, but the ozone concentration will be high than the use of natural air.
Secondly, besides oxygen, which occupies 21% of the quantity of the air, natural air contains nitrogen at a percentage of 78%. With the presence of nitrogen, using air as the feed gas of ozone generation will result in the existence of nitrogen oxides. If high-concentration ozone without any nitrogen oxides is demanded, then pure oxygen provided by an oxygen generator will be required in the ozone generation process.
In addition, when using natural air as the feed gas, ozone generators typically uses compressed air. But when the air is compressed, the moisture and oil components it contains condenses. In order to achieve the generation of high-concentration ozone and the reduction of damage to the ozone generator, the compressed air needs to be filtered and desiccated to remove the moisture and oil components before it is used in the ozone generator.
5. Effects of Temperature and Humidity on Ozone
In the above, we have introduced that different feed gases will affect the production and concentration of ozone. And different temperature and humidity conditions will also affect the sterilization of ozone.
Experiments have shown that ozone can react quickly with nitrogen monoxide (NO) in the air and form nitrogen dioxide (NO2). And the amount of NO2 will increase as the temperature rises. Therefore, when ozone is used, it is better to use it at lower temperature conditions.
Ozone also has a differentiated sterilization effect at different humidity conditions. When the humidity is higher, microbes’ cell membranes will swell and get thinner. The result is that their tissues will be more vulnerable to be damaged by ozone. So, ozone generators will be more effective in sterilization at a higher humidity conditions.