Indoor air quality (IAQ) is a significant concern, and it can impact our health and well-being in various ways. There are several tools and techniques that can improve IAQ, and one of the lesser-known contributors is lime, also known as calcium oxide. Lime has been used for centuries in various applications, including building materials, agriculture, and more. In this blog, we’ll explore lime’s contribution to indoor air quality and how it can benefit us.


What is IAQ?

IAQ stands for Indoor Air Quality, which refers to the quality of the air inside buildings, including homes, offices, schools, and other indoor environments. It is an important aspect of human health and well-being since we spend a significant amount of time indoors. IAQ can be affected by various factors, such as indoor pollutants, temperature, humidity, ventilation, and more.

Poor IAQ can lead to a range of health issues, such as respiratory problems, allergies, headaches, fatigue, and other illnesses. Therefore, it is essential to maintain a good IAQ to promote a healthy and comfortable indoor environment.


Absorption of Moisture

Lime, also known as calcium oxide, is a naturally occurring desiccant, which means it has the ability to absorb moisture from the air. Lime can absorb moisture through a chemical process called adsorption, which involves the attraction and adhesion of water molecules to the surface of the lime particles.

When lime is exposed to air, it reacts with water vapour in the air to form calcium hydroxide. This reaction is exothermic, meaning it releases heat. The heat generated by the reaction helps to accelerate the process of moisture absorption. Then, as the lime absorbs moisture, it becomes hydrated and begins to crumble into a finer powder which eventually self-repairs a building.

Lime’s ability to absorb moisture makes it an effective natural desiccant, which can help reduce humidity levels in indoor environments. High humidity can create conditions that promote the growth of mould and mildew, which can be harmful to human health. By using lime to absorb excess moisture, we can help prevent the growth of mould and maintain a healthy indoor environment. Lime will help keep the air dry, fresh, and healthy.


Neutralisation of Acids

Lime is a strong alkaline substance and can neutralise acids present in the air. Acids in the air can be generated from various sources, such as smoke, fumes, and other pollutants. These acids can be harmful to health, and they can cause damage to materials and surfaces in the indoor environment. Lime can absorb and neutralise these acids, making the air less corrosive and less harmful.


Odour Control

Lime mortar, which is made from lime, water and sand, has been used for centuries as a building material. It has a range of properties that make it suitable for use in construction, including its strength, durability, and breathability. However, in addition to its use as a building material, lime mortar has also been used as a deodoriser due to its ability to absorb and neutralise odours.

Lime mortar has alkaline properties that can help neutralise acidic compounds responsible for unpleasant odours. When lime mortar comes into contact with acidic compounds in the air, such as those produced by cooking, smoking, or pets, it reacts with them to form a less volatile and less odorous compound. This process has been used to deodorise buildings, such as churches and public buildings, for many years.

It is important to note that lime mortar should not be used as the sole means of controlling odours. It is most effective when used in combination with other measures, such as proper ventilation, cleaning, and odour-reducing practices. When used appropriately, lime mortar can be a useful tool for controlling odours in buildings, while also providing a natural and sustainable solution.


Antibacterial and Antifungal Properties

Lime, or calcium oxide, has been used for centuries for a variety of purposes, including as a building material, as well as for medicinal and culinary uses. One of its notable properties is its ability to act as a natural antibacterial and antifungal agent.

The alkaline nature of lime makes it an effective agent against bacteria and fungi. It can disrupt the cellular membranes of microorganisms, causing them to break down and die. Lime is particularly effective against Gram-positive bacteria, which are responsible for various infections and diseases, including streptococcal infections, pneumonia, and meningitis. Lime also has antifungal properties, which can help prevent the growth of fungi, including common types of mould.

In addition to its direct antimicrobial effects, lime can also be used to improve hygiene and reduce the risk of infection. Lime can be used to create an alkaline environment, which again, can help to prevent the growth of bacteria and fungi. It can also be used to disinfect surfaces, such as cutting boards or kitchen counters, by creating a solution of lime and water.

Overall, lime is a natural and effective agent for controlling the growth of bacteria and fungi. Its antibacterial and antifungal properties make it a useful tool for promoting hygiene and reducing the risk of infections, while also providing a natural and sustainable alternative to chemical disinfectants.



In conclusion, lime is a versatile and natural material that offers numerous benefits in improving air quality. Its ability to absorb and neutralise pollutants such as sulphur dioxide and nitrogen oxides, combined with its low cost and availability, makes it an attractive option for improving air quality in indoor settings. In addition, lime also helps to reduce the spread of harmful bacteria and mould, which can contribute to poor indoor air quality. Overall, the use of lime has the potential to significantly improve air quality and promote a healthier environment for all. By using lime, we can create a space that is not only aesthetically pleasing but also safe and healthy for occupants.