Measurements of size-fractionated concentration and bulk dry deposition of atmospheric particulate bound mercury

作者：Fang G C^*; Zhang L; Huang C S

来源：Atmospheric Environment, 2012, 61: 371-377.

DOI：10.1016/j.atmosenv.2012.07.052

• Atmospheric mercury
• Particle size distribution
• Fine/coarse fraction
• Surrogate surface measurements
• Dry deposition
• Deposition velocity
• Central Taiwan

Daily samples of size-fractionated (18, 10, 2.5 and 1.0 mu m) particulate-bound mercury Hg(p) were collected using Micro-Orifice Uniform Deposition Impactors (MOUDI), on randomly selected days each month between November 2010 and July 2011, at a traffic site (Hungkuang), a wetland site (Gaomei), and an industrial site (Quanxing) in central Taiwan. Bulk dry deposition was also collected simultaneously using a surrogate surface. The nine-month average (+/- standard deviation) Hg(p) concentrations were 0.57 (+/- 0.90), 0.17 (+/- 0.27), and 0.94 (+/- 0.92) ng m(-3) at Hungkuang, Gaomei, and Quanxing, respectively. Concentrations in November and December were much higher than in the other months due to a combination of high local emissions and meteorological conditions. PM 1.0 contributed more than 50% to the bulk concentration at the traffic and the industrial sites, but only contributed 25% at the wetland site. PM1.0-2.5 contributed 25%-50%, depending on location, to the bulk mass. Coarse fraction (PM2.5-18) contributed 7% at Hungkuang, 25% at Gaomei, and 19% at Quanxing. Samples with very high bulk concentrations had large fine fractions. Annual dry deposition estimated from the surrogate surface measurements was in the range of 30-85 mu g m(-2) yr(-1) at the three sites. Coarse particulate Hg(p) were estimated to contribute 50-85% of the total Hg(p) dry deposition. Daily dry deposition velocities (V-d) ranged from 0.01 to 7.7 cm s(-1). The annual V-d generated from the total measured fluxes was 0.34, 0.60 and 0.29 cm s(-1) at Hungkuang, Gaomei, and Quanxing, respectively. These values can be reasonably reproduced using a size-resolved model and measured size fractions.

• 出版日期2012-12