Passive soil gas surveys utilize adsorbent samplers that are emplaced subsurface to adsorb volatile and semivolatile organic compounds (VOCs and SVOCs) in soil gas without forcing the flow rate of gas, yielding a more representative sample than active soil gas methods. By sampling all locations at the same time, the temporal variations in soil-gas concentrations that are known to occur daily and even hourly are normalized. The analytical results for a passive soil gas survey are presented with accompanying color isopleth maps that depict the distribution of VOCs and SVOCs across the survey area 

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