Artifacts associated with the measurement of particulate mercury in an urban environment: The influence of elevated ozone concentrations
Artifacts associated with the measurement of particulate mercury in an urban environment: The influence of elevated ozone concentrations
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DOI：
10.1016/j.atmosenv.2005.01.036
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发表时间：
2005-06
影响因子：
5
通讯作者：
Mary M. Lynam;G. Keeler
中科院分区：
文献类型：
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作者：
Mary M. Lynam;G. Keeler
2001年7月和2002年7月，在底特律西南部对细微颗粒汞采样过程中臭氧造成伪影的可能性进行了调查。在2001年7月的抽样期间，使用放置在上游的KI和KCl去污管去除臭氧和活性气态汞Hg2+(G)，导致裸露过滤器上的颗粒汞更多(最高33pgm−3)，而不是裸露过滤器。此外，当臭氧浓度最高时，氯化钾裸露的石英过滤器也比未露出的过滤器显示更多的颗粒汞(最大12pgm−3)。2002年7月的进一步抽样采用了重复抽样设计，与裸露的过滤器相比，未封口的过滤器上的颗粒汞更多。2001年7月的情况以臭氧浓度升高为特征，在此期间，密歇根州宣布了三个臭氧行动日，而2002年7月的臭氧浓度降低了22%。对观察到的一种可能的解释可能是，元素汞Hg0(G)在采样过程中被氧化为活性气态汞Hg2+(G)，从而导致人工制品。在光化学活性高的时期，这种人工产物的可能性可能更大，在城市大气中可能存在高水平氧化剂的温暖季节采样时，必须考虑这一点。
The potential for ozone to cause an artifact during sampling of fine particulate mercury was investigated in southwest Detroit in July 2001 and July 2002. During the July 2001 sampling period, the use of KI and KCl denuders placed upstream to remove ozone and reactive gaseous mercury, Hg2+(g), resulted in more particulate mercury (maximum 33pgm−3) on a denuded filter when compared to an undenuded one. Additionally, a KCl denuded quartz filter also showed more particulate mercury (maximum 12pgm−3) compared to an undenuded filter when ozone concentrations were most elevated. Further sampling in July 2002 used a repeated sampling design and resulted in more particulate mercury on undenuded filters when compared to denuded ones. Conditions in July 2001 were characterized by elevated concentrations of ozone during which there were three ozone action days declared by the State of Michigan whereas ozone concentrations in July 2002 were 22% lower. One possible explanation for the observations may be that elemental mercury, Hg0(g), is oxidized to reactive gaseous mercury, Hg2+(g), during sampling leading to an artifact. The potential for this type of artifact may be greater during periods of high photochemical activity and this must be considered when sampling during the warmer seasons when high levels of oxidants are likely to be present in an urban atmosphere.