The U . S . Geological Survey developed SELDM in cooperation with the Federal Highway Administration to help develop planning-level estimates of event mean concentrations, flows, and loads in stormwater from a site of interest and from an upstream basin.
12.
With the normalization used in the previous section, " G " ( 0 ) gives the mean number of diffusers in the volume, or equivalently & mdash; with knowledge of the observation volume size & mdash; the mean concentration:
13.
Typical geometric standard deviations found in studies range between 2 and 3, meaning ( given the 68 95 99.7 rule ) that the radon concentration is expected to be more than a hundred times the mean concentration for 2 to 3 % of the cases.
14.
The living room had a mean of 18.1?7.5 ?g m " 3 and the bedroom was 18.2?6.9 ?g m " 3, whereas the outdoor air had a mean concentration of 2.3?.6 ?g m " 3.
15.
The global annual mean concentration of in the atmosphere has increased by more than 40 % since the start of the Industrial Revolution, from 280 ppm, the level it had for the last 10, 000 years leading up to the mid-18th century, to 399 ppm as of 2015.
16.
A study of the stability of chlorpropham in potatoes ( estimated concentration of chlorpropham : 1.8 to 7.6 mg / kg at 10 days post-application ) revealed that mean concentration of chlorpropham in the tuber decreased spontaneously by 24 % and 42 % at 28 days and 65 days postapplication respectively.
17.
According to the 2007 IPCC climate report, HFC-23 was the most abundant HFC in the global atmosphere until around 2001, which is when the global mean concentration of HFC-134a ( 1, 1, 1, 2-tetrafluoroethane ), the chemical now used extensively in automobile air conditioners, surpassed those of HFC-23.
