Dry and wet deposition of inorganic nitrogen at urban and rural sites in a semi-arid environment

Abstract

Dry and wet deposition of inorganic nitrogen species were monitored at one urban (SDS) and one rural (TFS) site during September 2009 and August 2010 at Urumqi in a semi-arid region. Atmospheric concentrations of NH3, NO2, HNO3, particulate ammonium and nitrate (pNH4+ and pNO3-) concentrations and NH4-N and NO3-N concentrations in precipitation showed large monthly variations and averaged 7.0, 18.2, 2.4, 6.6, 2.7 μg N m-3 and 1.3, 1.0 mg N L-1 at both SDS and TFS. Nitrogen dry deposition fluxes were 32.8 and 28.9 kg N ha-1 yr-1 while wet deposition of N fluxes were 6.0 and 8.8 kg N ha-1 yr-1 at SDS and TFS, respectively. Our results indicate that N dry deposition has been a major part of total N deposition (80.6% on average) in the semi-arid region. Such high N deposition implied the heavy environmental pollution and an important nutrient resource in arid and semi-arid regions. © 2012 IEEE.