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The AEGL values describe the expected effects of inhalation exposure to certain compounds (airborne concentrations in ppm or mg/m 3). Each AEGL is determined by different levels of a compound's toxicological effects, based on the 4 Ds: detection, discomfort, disability and death. There are three levels of AEGL-values: AEGL-1, AEGL-2 and AEGL-3. [2]
Many gases have toxic properties, which are often assessed using the LC 50 (median lethal concentration) measure. In the United States, many of these gases have been assigned an NFPA 704 health rating of 4 (may be fatal) or 3 (may cause serious or permanent injury), and/or exposure limits (TLV, TWA/PEL, STEL, or REL) determined by the ACGIH professional association.
The OSHA definition is arguably broad enough to include oxygen-deficient circumstances in the absence of "airborne contaminants", as well as many other chemical, thermal, or pneumatic hazards to life or health (e.g., pure helium, super-cooled or super-heated air, hyperbaric or hypo-baric or submerged chambers, etc.).
The TLV for chemical substances is defined as a concentration in air, typically for inhalation or skin exposure. Its units are in parts per million (ppm) for gases and in milligrams per cubic meter (mg/m 3 ) for particulates such as dust , smoke and mist .
DeCarlo said nearly all the readings were higher than 11 parts of ethylene oxide per 1 trillion parts of air — a level that translates to a one in 10,000 cancer risk for long-term exposure to ...
Some of the agencies that research and/or regulate chemicals include OSHA, [11] NIOSH, [12] and CDC, [13] to name a few along with numerous other state and professional organizations. The Occupational Safety and Health Administration (OSHA) is a regulatory agency that creates federal-level standards for pollutant gases, among many other health ...
There are three levels of PAC value (1 to 3) where each successive value is associated with an increasingly severe effect from a higher level of exposure. Each level is defined as follows: PAC-1 : Mild, transient health effects. PAC-2 : Irreversible or other serious health effects that could impair the ability to take protective action.
Growing evidence that air pollution—even when experienced at very low levels—hurts human health, led the WHO to revise its guideline (from 10 μg/m 3 to 5 μg/m 3) for what it considers a safe level of exposure of particulate pollution, bringing most of the world—97.3 percent of the global population—into the unsafe zone.