How many soil gas samples should be collected for sites smaller than 1,000 square feet?

The correct answer reflects guidelines that stipulate the number of soil gas samples needed to adequately assess potential contamination at smaller sites, specifically those that are less than 1,000 square feet. Collecting two samples provides a more reliable representation of the subsurface conditions compared to a single sample. This approach helps account for variability within the site, as soil gas concentrations can differ significantly even over short distances.

By taking two samples, environmental professionals can evaluate the potential for vapor intrusion and ensure that the data collected is robust enough to inform any necessary remediation strategies. This sampling strategy balances the need for sufficient data with the practical considerations of time and resource allocation that might be especially relevant for smaller sites.