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The primary standard was set at 9 ppm averaged over an 8-hour period and 35 ppm over a 1-hour period. [10] The majority of CO emitted into the ambient air is from mobile sources. The EPA has reviewed and assessed the current scientific literature with respect to CO in 1979, 1984, 1991, and 1994. [11]
Carbon dioxide concentrations in closed or confined rooms can increase to 1,000 ppm within 45 minutes of enclosure. For example, in a 3.5-by-4-metre (11 ft × 13 ft) sized office, atmospheric carbon dioxide increased from 500 ppm to over 1,000 ppm within 45 minutes of ventilation cessation and closure of windows and doors.
The original NAAQOs have not been formally revised to the new two-level system. As an interim approach, data are compared with the existing desirable and acceptable NAAQOs for sulphur dioxide, carbon monoxide, nitrogen dioxide and ozone. The air quality objectives must be consistent with the Canadian Environmental Protection Act (CEPA) 1999 ...
1 volume percent = 10,000 ppmv (i.e., parts per million by volume) with a million being defined as 10 6. Care must be taken with the concentrations expressed as ppbv to differentiate between the British billion which is 10 12 and the USA billion which is 10 9 (also referred to as the long scale and short scale billion, respectively).
The AQI level is based on the level of six atmospheric pollutants, namely sulfur dioxide (SO 2), nitrogen dioxide (NO 2), suspended particulates smaller than 10 μm in aerodynamic diameter (PM 10), [19] suspended particulates smaller than 2.5 μm in aerodynamic diameter (PM 2.5), [19] carbon monoxide (CO), and ozone (O 3) measured at the ...
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. The basic formula for converting between ppm and mg/m 3 for gases is ppm = (mg/m^3) * 24.45 / molecular weight. This formula is not applicable to airborne particles.
Unions say schools must be able to ‘escalate’ concerns with Government while managing the issue
A normal cubic meter (Nm 3) is the metric expression of gas volume at standard conditions and it is usually (but not always) defined as being measured at 0 °C and 1 atmosphere of pressure. A standard cubic foot (scf) is the USA expression of gas volume at standard conditions and it is often ( but not always ) defined as being measured at 60 ...