Song Xinjie, Cheng Irene, Lu Julia
Department of Chemistry and Biology, Ryerson University, 350 Victoria Street, Toronto, Ontario, Canada.
J Environ Monit. 2009 Mar;11(3):660-9. doi: 10.1039/b815435j. Epub 2009 Jan 7.
Real-time concentrations of atmospheric gaseous elemental mercury (GEM), reactive gaseous mercury (RGM), and mercury associated with particles having sizes <2.5 microm (P-Hg < 2.5) were simultaneously measured in downtown Toronto from December 2003 to November 2004. The annual mean concentrations of GEM, P-Hg < 2.5 and RGM were 4.5 +/- 3.1 ng m(-3) (99.2%), 21.5 +/- 16.4 pg m(-3) (0.5%) and 14.2 +/- 13.2 pg m(-3) (0.3%), respectively. The concentrations for all the measured Hg species were highly variable throughout the year and were lower in winter than in the other three seasons. The maximum concentrations of Hg species were observed in June and were a result of the high number of Hg spikes (using [GEM] >10 ng m(-3) as an indicator) that occurred in the month. Nighttime (between 9pm-6am) concentrations of Hg species were higher than those of daytime. The results revealed: (1) an urban area is a continuous source of Hg species that have the potential to pose impacts on local, regional and global scales; (2) local/regional anthropogenic sources contributed significantly to the levels and the distributions of the Hg species in the urban atmosphere. More studies are needed to identify and quantify the anthropogenic sources of Hg and the Hg species emitted from these sources; (3) surface emission and photochemical reactions (including the reactions involving ozone) did not have significant influence on the levels of Hg species and their distribution in the urban atmosphere.
2003年12月至2004年11月期间，在多伦多市中心同时测量了大气中气态元素汞（GEM）、活性气态汞（RGM）以及与粒径小于2.5微米的颗粒物相关的汞（P-Hg < 2.5）的实时浓度。GEM、P-Hg < 2.5和RGM的年均浓度分别为4.5±3.1纳克/立方米（99.2%）、21.5±16.4皮克/立方米（0.5%）和14.2±13.2皮克/立方米（0.3%）。所有测量的汞物种浓度全年变化很大，冬季低于其他三个季节。汞物种的最高浓度出现在6月，这是该月出现大量汞峰值（以[GEM] >10纳克/立方米为指标）的结果。汞物种的夜间（晚上9点至早上6点）浓度高于白天。结果表明：（1）城市地区是汞物种的持续来源，有可能对局部、区域和全球尺度产生影响；（2）当地/区域人为源对城市大气中汞物种的水平和分布有显著贡献。需要更多研究来识别和量化汞的人为源以及这些源排放的汞物种；（3）地表排放和光化学反应（包括涉及臭氧的反应）对城市大气中汞物种的水平及其分布没有显著影响。
