|Title||Phase partitioning and dry deposition of atmospheric nitrogen at the mid-Atlantic US coast|
|Publication Type||Journal Article|
|Year of Publication||2003|
|Authors||Russell, KM, William, KC, Maben, JR, Galloway, JN, Moody, JL|
|Journal||Journal of Geophysical Research-Atmospheres|
 The deposition of atmospheric nitrogen contributes significantly to total nitrogen (TN) entering U. S. coastal water bodies. Nitrogen inputs via wet deposition are well quantified but dry-deposition fluxes are uncertain. In this study, dry fluxes of major atmospheric nitrogen species ( including gaseous NH3 and HNO3 and particulate NH4+, NO3-, NO2-, and organic nitrogen (ON)) were quantified during a 2-week summer sampling period at Lewes, Delaware, on the mid-Atlantic U. S. coast. Results indicate that dry deposition contributed approximately 43% to total atmospheric nitrogen deposition. Under all flow conditions, NH3(g) accounted for the largest fraction of TN dry deposition ( averaging 60%); HNO3(g) and NO3- also contributed considerably ( averaging 25 and 8%, respectively). During onshore flow, scavenging of HNO3(g) by sea-salt aerosols shifted the phase partitioning and relative dry fluxes of total NO3 (HNO3(g) + NO3-) toward particulate NO3-. The mass-weighted deposition velocities for particulate NO3- ( associated primarily with sea-salt size fractions) were similar to those of HNO3(g). Consequently, phase changes did not substantially alter the dry-deposition fluxes of total NO3. In light of these results, dry-deposition monitoring programs at coastal locations should (1) quantify NH3(g) deposition; (2) reliably sample supermicron particles ( with which most particulate NO3- is associated); and (3) apply deposition models for particulate nitrogen that are consistent with corresponding size distributions.
|URL||<Go to ISI>://000186396400002|