We developed and validated an automated, inexpensive, and continuous multiple-species gas-flux monitoring system that can provide data for a variety of relevant atmospheric pollutants, including O<sub>3</sub>, CO<sub>2</sub>, and NO<sub>x</sub>. Validation consisted of conducting concurrent gas-phase dry-deposition experiments, using both dynamic flux chambers and an eddy-covariance system, in a grassy clearing in the Duke Forest (Chapel Hill, NC). Experiments were carried out in June and September, under a variety of meteorological conditions. Ozone-deposition measurements from the two methods matched very well (4–10% difference in mean flux rate) when the leaf-area index (LAI) inside the chambers was representative of the average LAI in the field. The dynamic flux chambers can be considered an accurate measurement system under these conditions. CO<sub>2</sub> measurements were conducted for one 20 h period, and the flux chamber captured the diurnal trend in CO<sub>2</sub> flux well, although the quantity of the data was not sufficient to validate chamber performance. Flux-chamber NO<sub>x</sub> measurements could be calculated when ambient NO<sub>x</sub> concentrations were above 1 ppb. Unfortunately, the eddy-covariance system for measuring NO<sub>x</sub> was not available during this field campaign, so comparisons cannot be made. NO<sub>x</sub> fluxes were in a reasonable range for the field site.