Malodours downgrade the healthy life quality !

Classification of odour :
1. pleasant odours : scents, perfumes, fragrances, aromas, bouquets.
2. unpleasant odours : stench, reek, stink, pong. Unpleasant odours usually called "Malodours".
"Odour" which also called "smell" is a volatile chemical compound generally at a very low concentration, that human perceive by the sense of olfaction.
The widest range of odours consist of organic compounds, but some inorganic copounds are also exist like Hydrogen-sulfide (H2S), Ammonia (NH3).
The perception of an odour effect is a two step process:
a. physiological part, with the odour-receptor located in the nose.
b. psychological part, which is processed by the region of human brain.


a. Physiological part : When we inhale odourants, the odorant- molecules adhere to our Olfactory nerve ending in the back of the nose oil.

b. Psychological part : the adherence of those odourant-molecules producing stimulation in the nose direct to the brain. This is very rapid and direct pathway to the part of the brain which direct, controls, interprets and responds to sensory input.


The odour-molecules send message to the Limbic system, the area in the brain that governs emotional responses, this messages have power to alter moods, for examples alertness, stress, sleepy, angry, general feeling of well-being etc. This is the concept of Aromatherapy !
The human nose has the ability to distinguish many thousands of different odours, and the memories of these odours are stored deep in our sub-concious mind.
Malodours :
"Malodour" is the term used to describe these unpleasant-odours, range in unpleasantness from being mildly dis-taste-ful to actually causing physical reactions such as nausea and / or vomitting. Examples of Malodours are rotting fish (trimethylamine); rotting flesh (tetra-ethylene-diaine); faecal (indole, skatole); fishy (trimethylamine); rancid-oils; rotten egg (HCN); food-wastes; LPG-smell (methyl, ethyl-mercaptane, tetra-hydro-thiophene - sulphur copounds), human-fishy-body-smell (triethylaminuria), Pet-odours, Pet-urines, skunk-smell (butyl-mercaptan); etc.
Malodours do not consist of one single component, usually they are a blend of several perhaps so many malodourous materials and many contain both sulphur and nitrogen containing compounds, occasionally also blend with fatty acids (rancid odour).
In general malodours can be classified under 3 (three) main catagories:
1. Nitrogen Compounds : normally amines and produce fishy, cadaverous and faecal odours, other nitrogen compounds contribute considerably to cigarette smoke odours.
2.Sulphur Compounds : consist of mainly organic sulphide and mercaptane, Sulphur compounds contribute rotting, skunk and cabbage-like odours.
3. Fatty Acids: These materials are associated with rancid odours, axillary odours (sweaty armpitsodours).
How to kill or to eliminate Malodours (Abatement) ?
The sources of malodours are to be found at anywhere, in the houses, like kitchens, bathrooms, toilets, domestic pets, drainages, carpets, curtains, building materials, and at outsides / outdoors, like people, industrial plants, public trasports, sewage plants etc.
There are many ways to eliminate malodours :
1. Physical control : by dilution
2. Biological control: maintain aerobic conditions, using mixture of enzymes, microbial nutrients, and deodorizing additives.
3. Chemical control :
(a). Odour masking : masking with chemicals, pine-resins, mint-odours in aerosol or powder froms. masking agents are most effective when they are used at the source of the malodours, but sometime are not very applicable, because they only alter the perceived odours. This is the basic of classical malodour couteraction.
(b). Odour compensation : uses a pair of well-defined products, a malodour and its antagonist, in a defined range of concentration the 2 (two) odourants cancelled each other out, unfortunately, the exact mechanism is not understood, it is most likely physiological, when the pairs (malodour and its antagonist) are mix at the correct concentration level, neither one of the is detected, principally this method could not be used alone because malodour are not produced by a single well-defined molecule, but are generally mixture of malodourous materials which is very in concentration with time. Example of these method : skatol and coumarin; ethyl-mercaptane and eucalyptol; methyl-salicylate and pyridin.
(c). Solubilisation : Dispensing a very fine spray of a non volatile odourless solvent in the atmosphere yields micro drops of the solvent with a high surface-to-mass ratio. These tiny droplets have the ability to dissolve organic molecules and since they tend to deposit by gravity, they will contribute to the reduction of the concetration of malodours in the air.
(d). Absoption : Filter through high absorptive capacity materials like Activated Carbon.
(e). Oxidation : using oxidazig agets, like Hydrogen-peroxide (H2O2), Potassium-permanganate (KMnO4), para-foraldehyde, ozone (O3), Chlorine (Sodium hypochlorite /NaOCl2, or Calcium hypochlorite /Ca0Cl2), Ozene or Ortho-dichloro-bezene.
(f). Additives : using deodorizing additives which are usually propietary mixture of chemicals and plant extracts, dried-bacteria, or dried-enzymes. Enzymes actually "eat" malodours and organic matters such as urine, faecal, vomit, grease etc.
(g). Chemical neutralisation : Since early 50's it has been claimed that certain esters containing reactive double bonds have a quasi (similiar) universal ability to abate malodours. Ester of methacrylic, fumaric, citraconic, acotinic, crotonic, tiglic, senecoic-acids have been patented for "true" malodour neutralisation. Examples are Lauryl-methacrylate; a mixture of Geranyl-crotonate and Dihexyl-fumarate.
Malodours actually can give a negative effect to health, disturb us in maintaining a healthy life style, they must be abated regularly, rutinely and consistantly !