Ozone- Learn main points

Ozone (O3) is a gas molecule of three oxygen atoms. Ozone, or “smog,” is harmful to the lungs—chemical reactions between ozone and lung tissue cause it to aggressively attack. When ozone is present, the same processes create other harmful pollutants.

The stratospheric ozone layer protects us from most UV rays. However, ozone air pollution in the troposphere, where we can breathe it, causes serious health issues.

Gases from tailpipes, smokestacks, and various other sources contribute to ozone formation in the atmosphere. This reaction occurs when these gases come into contact with sunlight.

Nitrogen oxides (NOx) and volatile organic compounds (VOCs) are the essential raw components for ozone production and Fossil fuels, such as gasoline, oil, and coal, and some chemicals, such as solvents, produce these emissions. Power plants, vehicles, and other sources of high-heat combustion all produce NOx. Refineries, factories, vehicles, chemical plants, and other sources emit VOCs.

The ingredients react to form ozone if present under the right conditions. Sunlight is vital. Because the reaction occurs in the atmosphere, the ozone often appears downwind of the original gas sources. Winds can also carry ozone long distances, even across borders and oceans.

Chemical Properties of Ozone – O3

When ozone dissolves in water, it forms hydrogen peroxide. Below is the chemical equation.

O3 + 3H2O → 3H2O2

Lead sulphide reacts with ozone to form lead sulphate. Below is the chemical equation.

3PbS + 4O3 → 3PbSO4

Uses of Ozone – O3

• We use Ozone water treatment plants without filtration systems.

• Photocopiers, laser printers, and other electrical devices can produce ozone.

• Ozone therapy disinfects and treats diseases by limiting the effects of bacteria, viruses, fungi, yeast, and protozoa.

• Several ozone-depleting compounds have properties that make them good refrigerants, and they can efficiently transfer heat from one location to another.

Who is at risk from breathing ozone?

When ozone pollution levels are high, people who spend a lot of time outdoors are at risk. Breathing ozone can have a particularly harmful effect on the following individuals:

• Teenagers and children

• Anyone aged 65 and over

• People with lung diseases like asthma and COPD (which includes emphysema and chronic bronchitis)

• Outdoor workers and exercisers

Some research also suggests that other groups, such as women, obese people, and those with low incomes, may be at greater risk from ozone. These findings require more research.

However, many factors can have an impact on your health. For example, if you’re working or exercising outdoors or spending a lot of time outside, the risk is higher if ozone levels are higher.

The Galveston lifeguard study showed the impact of even short-term ozone pollution exposure on healthy adults. Aside from particle pollution, lifeguards had more airway obstructions when ozone levels were high at the end of the day.

How does ozone affect the respiratory tract?

The upper respiratory tract is not as good at removing ozone from the air as it is for sulphur dioxide or chlorine gas (Cl2). Consequently, most inhaled ozone reaches the lower respiratory tract, where it dissolves in the thin layer of epithelial lining fluid (ELF) in the lung’s conducting airways.

The ozone in the lungs quickly reacts with biomolecules that contain thiol or amine groups or unsaturated carbon-carbon bonds. The ELF causes ozone exposure, which reacts with underlying epithelial cells, immune cells, and neural receptors in the airway wall, causing long-term effects. In some cases, the ozone itself may interact with these structures.

A layer of lung lining fluid extends from the large airways down to the alveolar region, where the protein and lipid content is as thin as 0.2 µm when inhaled into the respiratory tract. The primary target of ozone and its by-products are the respiratory epithelial cells. Lactate dehydrogenase and other intracellular enzymes and plasma components leak from damaged cells into the airway lumen. Epithelial cells attract polymorphonuclear leukocytes (PMNs), activate alveolar macrophages, and train events leading to lung inflammation. Antioxidants in cells and lining fluid may help protect against ozone and its reaction products.

What are the acute physiological and symptom effects of ozone?

Short-term ozone exposure primarily affects the body’s ability to inhale to its full lung capacity. Short-term human exposure causes a decrease in forced expiratory volume in one second (FEV1), decreased lung function, and the following respiratory symptoms:

• Cough

• Shortness of breath

• Irritation of the throat

• Taking a deep breath causes discomfort or pain in the chest.

The effects of exposure are reversible within a few hours to 48 hours, improving and returning to baseline.

Stimulating airway neural receptors (likely airway C-fibres) and transmission to the brain via afferent vagal nerve pathways causes symptoms and changes in lung function. Although ozone exposure causes some narrowing of the airways, the major reason for difficulties inhaling to full lung capacity is neural inhibition of inhalation effort at high lung volumes.

Conclusion

Ozone (O3) is a highly reactive three-oxygen atom gas. It is a natural and man-made product found in the earth’s upper (stratosphere) and lower (troposphere) atmospheres (the troposphere). Depending on where it is in the atmosphere, ozone has both positive and negative effects on life on earth.

Molecular oxygen and solar ultraviolet (UV) radiation interact to form stratospheric ozone (O2). The ozone layer, which is present between 6 and 30 miles above the earth’s surface, protects us from damaging UV radiation.

We breathe tropospheric or ground-level ozone because of photochemical reactions between two primary air pollutants, volatile organic compounds (VOC) and nitrogen oxides (NOx). Heat and sunlight are necessary for these reactions, resulting in higher ambient ozone concentrations during the summer.