Estimating uncertainty in Keeling’s CO₂ measurements. The manometer in Box 3-2 has the following key uncertainties:

Volume of large vessel: 5.0138₂ ± 0.0005 L

Volume of small vessel: 3.7930 ± 0.0009 mL

Pressure: ± 0.03 mm Hg in ~ 400 mm Hg

Temperature: ± 0.03 K in ~300 K

Which factor has the largest percent relative uncertainty? If one uncertainty is sufficiently larger than the others, then the uncertainty in measuring CO₂ is governed by that factor. Considering just the most uncertain factor, estimate the uncertainty in 400 ppm CO₂ in air.