1. A passive kinetic sampler for quantitative passive soil vapor concentration measurement comprising: a container filled with a sorbent medium and having one or more openings; wherein the sampler has an uptake rate and sampler dimensions that constrain the uptake rate to match values that minimize or eliminate a starvation effect as calculated via mathematical models; wherein the mathematical models calculate a diffusive delivery rate of vapors to a void space in which the passive sampler is deployed and depend at least in part on soil moisture and porosity; and wherein the uptake rate during a sampling interval, as constrained by the sampler dimensions, is less than or about the delivery rate of vapors from surrounding soil, so the concentration of vapors in the void space within which the sampler is exposed is similar to the concentration of vapors in the surrounding soil gas throughout a majority of the sampling interval, wherein the sampler dimensions include the total area of the one more openings through which the sorbent material is exposed to the void space and the container having a volume in the range of 0.8 to 5.0 mL; and wherein the uptake rate that minimizes the starvation effect is less than the diffusive delivery rate.