Improving mercury flux chamber measurements over water surface

A modified floating flux chamber was designed and used to measure mercury evasional fluxes in a coastal area of the Mediterranean Sea in different meteo-marine conditions during the hours of maximum insolation (PAR intensity 360-430 W m-2) in the summer season. The chamber has been modified providing a flap at the inlet port preventing the back-flow of air from the interior of the chamber. Results demonstrate that the modified flux chamber gives flux values noticeably higher both in rippled sea conditions (mean value 7.88+1.45 ng m-2 h-1) and in rough sea conditions (mean value 21.71+2.17 ng m-2 h-1) with respect to those obtained by using the unmodified chamber (respectively 5.23+0.67 and 14.15+1.03 ng m-2 h-1.