Temporal variation of total gaseous mercury in the air of Guiyang, China

Abstract

.[1] Total gaseous mercury (TGM) concentrations in ambient air were monitored at an urban site in Guiyang from 23 November 2001 to 30 November 2002 using a high temporal resolution 5 min mercury vapor analyzer (Tekran 2537A). TGM concentrations follow lognormal frequency distribution pattern, and the mean TGM concentration at the measurement site is 8.40 ng m À3 on the basis of 1 year observation. TGM concentrations in Guiyang are significantly elevated compared to the continental global background values. Coal combustion from both industrial and domestic uses is estimated to be the primary atmospheric source. A seasonal distribution pattern of TGM with a descending order of winter, spring, fall, and summer was observed. The highest TGM concentration in winter is attributed to household heating using coal. A consistent diurnal distribution pattern of TGM was obtained among all seasons, and the nighttime TGM concentration is elevated compared to the daytime values. Meteorological conditions are responsible for the formation of diurnal TGM distribution pattern. Tremendous efforts are needed to reduce mercury emissions from coal combustion to decrease TGM concentrations in Guiyang.

Characteristics and potential sources of atmospheric mercury at a subtropical near‐coastal site in East China

“…The highest monthly mean occurred in December (4.7 ng m À3 ). The higher TGM concentration in the cold season and lower concentration in the warm season are consistent with previous results at sites influenced by local anthropogenic Hg emissions in China [Feng et al, 2002[Feng et al, , 2003[Feng et al, , 2004Fu et al, 2012c;Wang et al, 2007]. This is in contrast to TGM concentrations observed at sites influenced by long transport [Fu et al, 2012a], during which dilution and mixing by air masses can influence the dispersion of Hg plumes.…”

“…Another possible reason is the diurnal wind pattern. Atmospheric Hg released from industrial areas adjacent to DAO was enriched during the night due to the shallow nocturnal boundary layer [Feng et al, 2004;Fu et al, 2012b;Lee et al, 1998]. After sunrise, the plume was uplifted to the monitoring site.…”

“…Such concentration spikes (≥15.0 ng m À3 and up to 30.1 ng m À3 ) occurred in short durations (<30 min) and were commonly observed at urban sites [Feng et al, 2004;Friedli et al, 2011;Song et al, 2009]. These events were associated with different wind directions and speeds, suggesting different emission sources.…”

Progress of Global Atmospheric Mercury Field Observations

“…the elemental mercury (Hg 0 ), reactive gaseous mercury (RGM, Hg 2+ ) and particulate mercury (Hg P ). Hg 0 is the main chemical speciation of atmospheric mercury, which constitutes the majority of the mercury in the atmosphere over 95% [4]. As Hg 0 has very low solubility in water and its chemical reaction rate is very slow with other components in the atmosphere such as the strong oxidant O 3 , H 2 O 2 , OH and NO 3 radicals, Hg 0 has a long atmospheric lifetime (0.5 ~ 2 years) and was transmitted through the atmosphere thousands of kilometers [4].…”

“…Hg 0 is the main chemical speciation of atmospheric mercury, which constitutes the majority of the mercury in the atmosphere over 95% [4]. As Hg 0 has very low solubility in water and its chemical reaction rate is very slow with other components in the atmosphere such as the strong oxidant O 3 , H 2 O 2 , OH and NO 3 radicals, Hg 0 has a long atmospheric lifetime (0.5 ~ 2 years) and was transmitted through the atmosphere thousands of kilometers [4]. In the long-distance transport, Hg 0 may have a chemical reaction with atmospheric oxidants such as O 3 , H 2 O 2 , and halogen element and result in the formation of Hg 2+ , which reach the ground by dry and wet deposition and effect the global ecological environment [5] [6].…”