scholarly journals Nonmethane Hydrocarbons in Ambient Air of Hazy and Normal Days in Foshan, South China

2012 ◽  
Vol 29 (4) ◽  
pp. 262-269 ◽  
Author(s):  
Songjun Guo ◽  
Fumo Yang ◽  
Jihua Tan ◽  
Jingchun Duan
Keyword(s):  
South China ◽  
Ambient Air ◽  
Nonmethane Hydrocarbons

Measurements of atmospheric gaseous elemental mercury (GEM) and GEM fluxes in the seas of Southeast Asia in October-December 2019

2020 ◽  
Author(s):  
Viktor Kalinchuk ◽  
Evgeny Lopatnikov ◽  
Anatoly Astakhov ◽  
Maksim Ivanov ◽  
Renat Shakirov ◽  
...  
Keyword(s):  
South China Sea ◽  
Sea Of Japan ◽  
South China ◽  
Elemental Mercury ◽  
Ambient Air ◽  
The South China Sea ◽  
The Sea Of Japan ◽  
The South ◽  
Gaseous Elemental Mercury ◽  
China Sea

<p>Measurements of gaseous elemental mercury (GEM) in the marine boundary layer (MBL) and GEM evasion fluxes were carried out during the Russian-Vietnam cruise conducted from the Sea of Japan to the South China Sea from October 25 to December 7, 2019. All GEM measurements were performed using two RA-915M mercury analysers (Lumex LLC, Russia). Atmospheric GEM concentrations were measured at two levels (about 2 m and 20 m above the sea surface) with a time resolution of 30 minutes. GEM fluxes were measured in the South China Sea using a dynamic flux chamber.</p><p>GEM concentrations ranged between 0.56 ng/m<sup>3</sup> and 25.47 ng/m<sup>3</sup>, and between 0.39 ng/m<sup>3</sup> and 23.95 ng/m<sup>3</sup> with medians of 1.38 ng/m<sup>3</sup> and 1.45 ng/m<sup>3</sup> for 2 m and 20 m measurements, respectively. GEM concentrations were significantly affected by air transport of GEM. Concentration Weighted Trajectory (CWT) analysis showed several source regions potentially influencing GEM concentrations in the ambient air during the cruise: the south of the South China Sea, Vietnam, the southeastern China, the south of Japan and the Korean peninsula. Maximum concentrations (up to 25 ng/m<sup>3</sup>) were registered in Haiphong (Vietnam).</p><p>Hg(0) fluxes measured at 7 stations in the South China Sea ranged from 1.1 ng/m<sup>2</sup>/h to 2.5 ng/m<sup>2</sup>/h, with median value of 2.07 ng/m<sup>2</sup>/h. These values were 1,5 times higher than those that were measured by the same method in the Sea of Japan and the Sea of Okhotsk a month earlier.</p><p>This work was supported by the Russian Science Foundation (RSF) (Project № 19-77-10011).</p>

Nonmethane hydrocarbons in the transported and local air masses at a clean remote site on Hainan Island, south China

2007 ◽  
Vol 112 (D14) ◽  
Author(s):  
Jian-Hui Tang ◽  
Lo-Yin Chan ◽  
Chuen-Yu Chan ◽  
Yok-Sheung Li ◽  
Chih-Chung Chang ◽  
...  
Keyword(s):  
South China ◽  
Hainan Island ◽  
Nonmethane Hydrocarbons ◽  
Remote Site ◽  
Air Masses

scholarly journals Atmospheric total gaseous mercury (TGM) concentrations and wet and dry deposition of mercury at a high-altitude mountain peak in south China

2009 ◽  
Vol 9 (6) ◽  
pp. 23465-23504 ◽  
Author(s):  
X. W. Fu ◽  
X. Feng ◽  
Z. Q. Dong ◽  
R. S. Yin ◽  
J. X. Wang ◽  
...  
Keyword(s):  
South China ◽  
Dry Deposition ◽  
Urban Areas ◽  
Wet Deposition ◽  
Ambient Air ◽  
Total Gaseous Mercury ◽  
Deposition Fluxes ◽  
Wet And Dry Deposition ◽  
Gaseous Mercury ◽  
Seasonal And Diurnal Variations

Abstract. China is regarded as the largest contributor of mercury (Hg) to the global atmospheric Hg budget. However, concentration levels and depositions of atmospheric Hg in China are poorly known. Continuous measurements of atmospheric total gaseous mercury (TGM) were carried out from May 2008 to May 2009 at the summit of Mt. Leigong in south China. Wet and dry deposition fluxes of Hg were also calculated following collection of precipitation, throughfall and litterfall. Atmospheric TGM concentrations averaged 2.80±1.51 ng m−3, which was highly elevated compared to global background values but much lower than semi-rural and industrial/urban areas in China, indicating great emissions of Hg in central, south and southwest China. Seasonal and diurnal variations of TGM were observed, which reflected variations in source intensity, deposition processes and meteorological factors. Wet deposition of Hg was quite low, while its dry deposition of Hg (litterfall + throughfall-direct wet deposition) constituted a major portion of total deposition (~88% for total mercury (THg) and 84% for methyl mercury (MeHg)). This highlights the importance of vegetation to Hg atmospheric cycling. In a remote forest ecosystem of China, dry deposition of TGM, especially gaseous elemental mercury (GEM), was very important for the depletion of atmospheric Hg. Elevated TGM level in ambient air may accelerate the foliar uptake of Hg through air which may partly explain the elevated Hg dry deposition fluxes observed in Mt. Leigong.

scholarly journals Receptor Model Source Apportionment of Nonmethane Hydrocarbons in Mexico City

2002 ◽  
Vol 2 ◽  
pp. 844-860 ◽  
Author(s):  
V. Mugica ◽  
J. Watson ◽  
E. Vega ◽  
E. Reyes ◽  
M.E. Ruiz ◽  
...  
Keyword(s):  
Mexico City ◽  
Motor Vehicle ◽  
Ambient Air ◽  
Nonmethane Hydrocarbons ◽  
Receptor Model ◽  
Liquefied Petroleum Gas ◽  
Vehicle Exhaust ◽  
Source Profiles ◽  
Source Contributions ◽  
Initial Source

With the purpose of estimating the source contributions of nonmethane hydrocarbons (NMHC) to the atmosphere at three different sites in the Mexico City Metropolitan Area, 92 ambient air samples were measured from February 23 to March 22 of 1997. Light- and heavy-duty vehicular profiles were determined to differentiate the NMHC contribution of diesel and gasoline to the atmosphere. Food cooking source profiles were also determined for chemical mass balance receptor model application. Initial source contribution estimates were carried out to determine the adequate combination of source profiles and fitting species. Ambient samples of NMHC were apportioned to motor vehicle exhaust, gasoline vapor, handling and distribution of liquefied petroleum gas (LP gas), asphalt operations, painting operations, landfills, and food cooking. Both gasoline and diesel motor vehicle exhaust were the major NMHC contributors for all sites and times, with a percentage of up to 75%. The average motor vehicle exhaust contributions increased during the day. In contrast, LP gas contribution was higher during the morning than in the afternoon. Apportionment for the most abundant individual NMHC showed that the vehicular source is the major contributor to acetylene, ethylene, pentanes, n-hexane, toluene, and xylenes, while handling and distribution of LP gas was the major source contributor to propane and butanes. Comparison between CMB estimates of NMHC and the emission inventory showed a good agreement for vehicles, handling and distribution of LP gas, and painting operations; nevertheless, emissions from diesel exhaust and asphalt operations showed differences, and the results suggest that these emissions could be underestimated.

scholarly journals Atmospheric gaseous elemental mercury (GEM) concentrations and mercury depositions at a high-altitude mountain peak in south China

2010 ◽  
Vol 10 (5) ◽  
pp. 2425-2437 ◽  
Author(s):  
X. W. Fu ◽  
X. Feng ◽  
Z. Q. Dong ◽  
R. S. Yin ◽  
J. X. Wang ◽  
...  
Keyword(s):  
North America ◽  
South China ◽  
Urban Areas ◽  
Elemental Mercury ◽  
Ambient Air ◽  
Industrial Emissions ◽  
Deposition Fluxes ◽  
Gaseous Elemental Mercury ◽  
Seasonal And Diurnal Variations ◽  
Deposition Processes

Abstract. China is regarded as the largest contributor of mercury (Hg) to the global atmospheric Hg budget. However, concentration levels and depositions of atmospheric Hg in China are poorly known. Continuous measurements of atmospheric gaseous elemental mercury (GEM) were carried out from May 2008 to May 2009 at the summit of Mt. Leigong in south China. Simultaneously, deposition fluxes of THg and MeHg in precipitation, throughfall and litterfall were also studied. Atmospheric GEM concentrations averaged 2.80±1.51 ng m−3, which was highly elevated compared to global background values but much lower than semi-rural and industrial/urban areas in China. Sources identification indicates that both regional industrial emissions and long range transport of Hg from central, south and southwest China were corresponded to the elevated GEM level. Seasonal and diurnal variations of GEM were observed, which reflected variations in source intensity, deposition processes and meteorological factors. Precipitation and throughfall deposition fluxes of THg and MeHg in Mt. Leigong were comparable or lower compared to those reported in Europe and North America, whereas litterfall deposition fluxes of THg and MeHg were higher compared to Europe and North America. This highlights the importance of vegetation to Hg atmospheric cycling. In th remote forest ecosystem of China, deposition of GEM via uptake of foliage followed by litterfall was very important for the depletion of atmospheric Hg. Elevated GEM level in ambient air may accelerate the foliar uptake of Hg through air which may partly explain the elevated litterfall deposition fluxes of Hg observed in Mt. Leigong.

scholarly journals The Effects of Temperature on the Foraging Activity of Red Imported Fire Ant Workers (Hymenoptera: Formicidae) in South China

Sociobiology ◽  
2014 ◽  
Vol 59 (2) ◽  
pp. 573 ◽  
Author(s):  
Yong Yue Lu
Keyword(s):  
Ambient Temperature ◽  
South China ◽  
Soil Surface ◽  
Ambient Air ◽  
Fire Ants ◽  
Fire Ant ◽  
Red Imported Fire Ant ◽  
Foraging Activity ◽  
Effects Of Temperature ◽  
Imported Fire Ant

In this study, we investigated the effects of temperature of the ambient air, ground surface, and the soil at 5-cm deep on the foraging activity of the workers of red imported fire ant, Solenopsis invicta Buren, in South China with the method of bait traps. Significant correlations were observed between the temperature and the foraging activity of fire ants. Specifically, when the ambient temperature was above 20 °C, the fire ants foraged actively, and the activity reached a maximum when the ambient temperature was between 25 to 33 °C. But the foraging activity decreased as the ambient temperature rose higher than 34 °C. Moreover, fire ants were found to forage at maximal rates with the soil surface temperature between 27 to 40 °C. The ants started foraging when the soil temperature at 5-cm deep was between 16 to 48 °C, while 28~37 °C was the optimal temperature for the foraging activity. The extreme temperature thresholds for foraging of the ambient air, soil-surface, and soil at 5-cm deep were 11 °C/44 °C, 10 °C/57 °C, and 12 °C/48 °C respectively. 

Development of a Rapid Survey Method of Sampling and Analysis for Asbestos in Ambient Air

1972 ◽  
Vol 30 ◽  
pp. 630-631 ◽  
Author(s):  
R. E. Heffelfinger ◽  
C. W. Melton ◽  
D. L. Kiefer ◽  
W. M. Henry ◽  
R. J. Thompson
Keyword(s):  
Neutron Activation ◽  
Ambient Air ◽  
Survey Method ◽  
Potential Hazard ◽  
Transmission Microscopy ◽  
Comparative Analyses ◽  
Asbestos Fibers ◽  
Controlled Conditions ◽  
Unequivocal Identification ◽  
Identification And Quantification

A methodology has been developed and demonstrated which is capable of determining total amounts of asbestos fibers and fibrils in air ranging from as low as fractional nanograms per cubic meter (ng/m3) of air to several micrograms/m3. The method involves the collection of samples on an absolute filter and provides an unequivocal identification and quantification of the total asbestos contents including fibrils in the collected samples.The developed method depends on the trituration under controlled conditions to reduce the fibers to fibrils, separation of the asbestos fibrils from other collected air particulates (beneficiation), and the use of transmission microscopy for identification and quantification. Its validity has been tested by comparative analyses by neutron activation techniques. It can supply the data needed to set emissions criteria and to serve as a basis for assessing the potential hazard for asbestos pollution to the populace.

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