Carbon monoxide:
It is an asphyxiant. An accumulation of this odourless, colourless gas may result in a varied constellation of symptoms deriving from the compound's affinity for and combination with haemoglobin, forming carboxyhaemoglobin (COHb) and disrupting oxygen transport. The elderly persons with cardiovascular and pulmonary diseases are particularly sensitive to elevated CO levels. Methylene chloride, found in some common household products, such as paint strippers, could be metabolized to form carbon monoxide, which combines with haemoglobin to form COHb.
Carboxyhaemoglobin levels and related health effects
| % COHb in blood | Effects Associated with this COHb Level |
| 80 | Death |
| 60 | Loss of consciousness; death if exposure continues |
| 40 | Confusion; collapse on exercise |
| 30 | Headache; fatigue; impaired judgment |
| 7 - 20 | Statistically significant decreased maximal oxygen consumption during strenuous exercise in healthy young men |
| 5 -17 | Statistically significant diminution of visual perception, manual dexterity ability to learn, or performance in complex sensor motor tasks (such as driving) |
| 5 - 5.5 | Statistically significant decreased maximal oxygen consumption and exercise time during strenuous exercise in young healthy men |
| Below 5 | No statistically significant vigilance decrements after exposure to CO |
| 2.9 - 4.5 | Statistically significant decreased exercise capacity (i.e., shortened duration of exercise before onset of pain) in patients with angina pectoris and increased duration of angina attacks |
| 2.3-4.3 | Statistically significant decreased (about 3-7%) work time to exhaustion in exercising healthy men |
Particulate Matters (PM)
Particulate matter, in all, is one of the six criteria pollutants, and the most important in terms of adverse effects on human health. It’s basically a mixture of solid and liquid droplets, suspended in the atmosphere.
Health hazards caused due to particulate matters would lead to premature mortality, chronic respiratory disease, weakening of eyesight, aggravation of pre-existing heart and lung ailments and asthma.
Nitrogen dioxide (NO2) and sulphur dioxide (SO2)
They mainly act as irritants, affecting the mucous of the eyes, nose, throat, and respiratory tract. Acute S02-related bronchial constriction may also occur in people with asthma or as a hypersensitivity reaction. Extremely high-dose exposure (as in a building fire) to N02 may result in pulmonary oedema and diffuse lung injury. Continued exposure to high N02 levels can contribute to the development of acute or chronic bronchitis.
The relatively low water solubility of N02 results in minimal mucous membrane irritation of the upper airway. The principal site of toxicity is the lower respiratory tract. Recent studies indicate that low-level N02 exposure may cause increased bronchial reactivity in some asthmatics, decreased lung function in patients with chronic obstructive pulmonary disease, and an increased risk of respiratory infections, especially in young children.
The high water solubility of S02 causes it to be extremely irritating to the eyes and upper respiratory tract. Concentrations above six parts per million produce mucous membrane irritation. Epidemiological studies indicate that chronic exposure to S02 is associated with increased respiratory symptoms and decrements in pulmonary function. Clinical studies have found that some asthmatics respond with bronchoconstriction to even brief exposure to S02 levels as low as 0.4 parts per million.
Volatile Organic Compounds (VOCs): Benzene, Toluene, Trichloroethylene and Formaldehyde etc.
Volatile organic compounds (VOCs) emitted as gases from certain solids or liquids. VOCs include a variety of chemicals. Concentrations of many VOCs are consistently higher indoors (up to ten times higher) than outdoors. The main sources are paints, paint strippers, and other solvents, wood preservatives, aerosol sprays, cleansers and disinfectants, moth repellents and air fresheners, stored fuels and automotive products.
No standards have been set for VOCs in non-industrial settings. OSHA regulates formaldehyde, a specific VOC, as a carcinogen. OSHA has adopted a Permissible Exposure Level (PEL) of 0.75 ppm, and an action level of 0.5 ppm. HUD has established a level of 0.4 ppm for mobile homes. Based upon current information, it is advisable to mitigate formaldehyde that is present at levels higher than 0.1 ppm.
Eye, nose, and throat irritation, headaches, loss of coordination, nausea, damage to liver, kidney, and central nervous system. Some organics can cause cancer in humans. Key symptoms associated with exposure to VOCs include conjunctival irritation, nose and throat discomfort, headache, allergic skin reaction, dyspnea, declines in serum cholinesterase levels, nausea, emesis, epistaxis, fatigue, dizziness.
Carbon Dioxide (CO2, 0.035 percent in atmosphere)
Carbon dioxide (CO2) is a colourless, odourless gas formed by metabolic activity, combustion activities, and motor vehicles in garages. Though carbon dioxide is not toxic itself, the amount found in the indoor environment is used as an indicator for human comfort. Elevated levels of carbon dioxide indicate that an insufficient amount of fresh, outdoor air is being delivered to the occupied areas of the building. This also indicates that other pollutants in the building may exist at elevated levels since there is not enough fresh air to dilute them. Since carbon dioxide is an unavoidable, predictable, and easily measured product of human occupancy, it is a basic indicator.
§ Headaches (7.5 percent)
§ Dizziness (7.5 percent)
§ Restlessness (7.5 percent)
§ Feeling of an inability to breathe (7.5 percent)
§ Sweating (7.5 percent)
§ Malaise (vague feeling of discomfort) (7.5 percent)
§ Increased heart rate (7.5 percent)
§ Increased blood pressure (7.5 percent)
§ Visual distortion (7.5 percent)
§ Impaired hearing (10 percent)
§ Nausea/vomiting (10 percent)
§ Loss of consciousness (10 percent)
§ Coma (30 percent)
§ Convulsions (30 percent)
§ Death from asphyxiation (30 percent, although several deaths have been reported at concentrations greater than 20 percent). With asphyxiation, body cells do not get the oxygen they need to live
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