| Component | Percentage by Volume | Characteristics | Effects |
|---|---|---|---|
| Methane | 45–60 | Methane is a naturally occurring gas. It is colourless and odourless. Largest LFG emitted from landfill, it is a Greenhouse Gas (GHG), highly flammable. | Global warming, major cause of landfill fire |
| Carbon dioxide | 40–60 | Carbon dioxide is colourless, odourless, and slightly acidic. It exists in the earth’s atmosphere at a concentration of 0.04 (400 ppm) percent by volume. It is a GHG. | Global warming, major source of ocean acidity |
| Nitrogen | 2–5 | Nitrogen comprises approximately 79% of the atmosphere. It is odourless, tasteless, and colourless. | Oxides of Nitrogen (NOx) are toxic gases, source of smog and acid rain; respiratory problems, lung damage. Nitrites and nitrates can cause cancer, thyroid problems. |
| Oxygen | 0.1–1 | Oxygen comprises approximately 21% of the atmosphere. It is odourless, tasteless, and colourless. | Iron rusting, supports combustion in landfill fires, excess oxygen at partial pressure can lead to severe health problem like cells damage, brain damage. |
| Ammonia | 0.1–1 | Ammonia is a colourless gas with a pungent odour. Corrosive gas, highly irritating. | Burning of nose, throat and respiratory tract, coughing, skin and eye irritation. Pungent and suffocating odour. Eutrophication, soil acidification. |
| NMOCs (non-methane organic compounds) |
0.01–0.6 | NMOCs are organic compounds (i.e., compounds that contain carbon). (Methane is an organic compound but is not considered a NMOC.) NMOCs may occur naturally or be formed by synthetic chemical processes. NMOCs most commonly found in landfills include acrylonitrile, benzene, 1,1-dichloroethane, 1,2-cis trichloroethylene, dichloromethane, carbonyl sulphide, ethyl-benzene, hexane, methyl ethyl ketone, tetrachloroethylene, toluene, trichloroethylene, vinyl chloride, and xylenes. | Carcinogenic, leukaemia, headaches, nausea. Some of the gases are highly flammable, pungent odour. |
| Sulphides | 0–1 | Sulphides (e.g., hydrogen sulphide, dimethyl sulphide, mercaptans) are naturally occurring gases that give the landfill gas mixture its rotten-egg smell. Sulphides can cause unpleasant odours even at very low concentrations. | Irritation to the eye, nose and throat, breathing difficulty, poor memory, tiredness. Pungent odour, |
| Hydrogen | 0–0.2 | Hydrogen is an odourless, colourless gas, tasteless, highly combustible, light gas. | Supports burning in landfill fires, |
| Carbon monoxide | 0–0.2 | Carbon monoxide is an odourless, colourless gas. | Reduces oxygen circulation in the body, vision problems, reduced manual dexterity and even death and formation of smog. |