Effectiveness of Odour Removal Agents

CHAPTER 1: INTRODUCTION

1.1 Background Information

With society becoming more modernised, most people are becoming more aware of their personal image. One of the many important factors that contribute to personal image is body scent. It allows people to present themselves better in front of others. [1] On the other hand, body odour has a negative impact on their physical image. It is thus necessary to consider body odour along with personal style and appearance.

Body odour, or body smell, is caused by bacteria growing on the body which multiply rapidly in the presence of sweat. [2] It is a natural process involving sweat that occurs on the skin's surface. Though sweat is odourless, bacteria that exist on the skin will feed on the sweat and break it down. This process releases chemicals that cause an unpleasant smell. Scientific study has shown that some areas of the skin, such as the armpits and genitals, are more likely to produce body odour because these glands produce proteins and oily substances that bacteria feed on. [3] The odour can also be caused by the formation of mildew which is due to moist and humid environment and is often seen as a whitish to bluish-green substance. [4] In addition to the unpleasant odour, the mildew decolorizes the clothing, and has a rotting effect on the fabrics.

Studies have shown that the major microorganisms that are responsible for the characteristic odours of the human body are Staphylococcus epidermidis and Propionibacteria. They reside on human skin which produce certain acids in small quantities.[5] Isovaleric acid (3-methyl butanoic acid) is one type of acid, which causes body odour as a result of actions of the bacteria Staphylococcus epidermidis. The other common source of odour is due to propionic acid (propanoic acid), which results from the breakdown of amino acids by Propionibacteria that thrive in the ducts of adolescent and adult sebaceous glands. These microorganisms and chemicals are taken up by the clothes, giving off odour even after washing.

Hence, odour removal agents play an essential role in removing the odour which is caused by bacteria and mildew. Sunlight is a natural odour removal agent and it consists of four spectrums of light namely; Ultraviolet A, B, C and visible light. Of these four spectrums, UV light C, known as germicidal irradiation, is capable of killing micro-organisms. [6] Several odour removal agents are available, such as washing detergents and these detergents have been used commonly to enhance the fragrance on clothing.[7] Also, common household methods such as adding vinegar, baking soda, and even salt together with detergents can enhance the removal of odour. [8] Urban myths have stated the effectiveness of these specific household agents. However, no research has been done on the effectiveness of these agents on removing odour from washed clothes.

1.2 Objective

The main aim of this research study is to determine the effectiveness of sunlight in removing odour of clothes after washing, and also to find alternative solutions in place of sunlight to remove odour during rainy or humid days, using the three additives: vinegar, baking soda, and salt.

1.3 Scope of the Study

In the present work, the effectiveness of four removal agents: sunlight and detergent with vinegar, baking soda and salt to remove odour on clothes after washing was tested. Each additive was mixed with detergent in the assigned washing machines. The clothes that were washed with detergent and additives were hung indoors to dry without sunlight. The other two clothes were washed with solely detergent, after which one was dried under sunlight and another was dried in the absence of sunlight. These clothes were then compared for the presence of odour and mildew.

1.4 Organization

This report is organized as follows: Chapter 2 describes the materials and procedures carried out in the preparation of the dirty clothes, how they were washed and dried to determine the effectiveness of the different agents in the removal of odour. This is followed by presentation and discussion of results in Chapter 3, and finally the conclusion in Chapter 4.

CHAPTER 2: METHODLOGY OF TESTING THE EFFECTIVENESS OF ODOUR-REMOVAL AGENTS

2.1 Introduction

The effectiveness of sunlight, and the mixing of detergent with the selected additives: vinegar, baking soda or salt to remove odour from clothes are compared in this study. This chapter describes the materials used, preparation methods, experimental procedures and data treatment.

2.2 Materials Used

Five similar black shirts made of 100% cotton were used for the experiment. Dynamo detergent was used together with common household vinegar, baking soda and salt.

2.3 Preparation of Sweaty Clothing

Five sweaty shirts were put into one tub of water to keep the degree of sweatiness constant for all the shirts.

2.4 Procedures for Washing and Drying of Clothes

The five black shirts were soaked in a pail containing four litres of water for three hours. All five shirts were also washed concurrently in separate washing machines for 43 minutes. Shirts A and B were washed solely with 15 ml of Dynamo detergent. Shirt C was washed with 15ml of Dynamo detergent and 15 ml of baking soda, while Shirt D was washed with 15 ml of Dynamo detergent and 15 ml of salt. Lastly, Shirt E was washed with 15 ml of Dynamo detergent and 15 ml of vinegar. After washing, Shirt A was hung out to dry under sunlight. The rest of the shirts (B, C, D& E) were hung indoors with proper ventilation and without sunlight. After six hours, the clothes were taken down and kept separately in five separate plastic bags for three days. After that, the shirts were taken out from the plastic bags, and analysed for the presence of odour and white traces of mildew.

2.5 Data Treatment

The experiment was repeated on different days to attain greater accuracy of the results. An analysis of variance was performed to compare the smell of the shirts dried in different weather conditions, namely: sunny, cloudy and windy. The clothes were then tested for odour by smelling and by comparing with two controls- a clean, odourless shirt and a sweaty shirt. In addition, the shirts were analysed for the presence of white traces of mildew.

2.6 Summary

In summary, five similar shirts were washed in different washing machines, with detergent and different additives