6. "In evaluating indoor air concentrations of carcinogenic or toxic compounds, some confusion exists over the...
6. "In evaluating indoor air concentrations of carcinogenic or toxic compounds, some confusion exists over the various units in use. Common units of indoor air measurements include ug/m3 or mg/m3, ug/L or mg/L, ppbV and ppmV. The confusion arises in converting from mass-per-volume to parts-per- number-volume units. It is important to remember that ug/L in gas systems IS NOT equal to ppbV, nor is mg/L in gas systems equal to ppmV. Each of these conversions is dependent upon the molecular weight of the contaminant and the temperature and pressure of the system." (US-EPA) Most ozone (about 90%) resides in the stratosphere. The remainingozoneisint etroposphere There are about 3 molecules of ozone for every 10 million molecules of air in the stratosphere. Express this concentration in ugm Assume 25 cC and latm.(15 pts) PV = nRT, where R = 0.082 (L-atm) / (mol ·K) OK = °C + 273 1L-10-3m3 mul -| .010 X 10" 7 mol x1o-17 latm 10-IULİx.ce oon' ะ 4.buo x1o". Crn3 IL x10-13 12 molecules Chy 3