Construction of a low-cost automated chromatographic system for the measurement of ambient methane

Wang, Jia Lin; Kuo, Show Ru; Si, Shen; Chen, Tai Yih

doi:10.1016/s0003-2670(01)01316-2

Cited by 7 publications

(2 citation statements)

References 15 publications

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“…Under these conditions, a southerly wind due to the sea breeze circulation system generally dominates during the daytime and it brings pollutants emitted around the coastal area of Tokyo Bay to the Komaba site and further inland (Figure 4) [ Uno et al , 1984; Wakamatsu et al , 1983]. The mixing ratio enhancements in the early morning can be attributed to the accumulation of the trace gases in the nocturnal inversion formed by the radiation of heat from the ground at night [ Wang et al , 2001]. The afternoon peaks are interpreted to be the passage of the residual of the previous day's emission transported by the daytime sea breeze from the marine boundary layer in Tokyo Bay, where it has been stalled during the night, entraining fresh on‐site emissions en route.…”

Section: Resultsmentioning

confidence: 99%

Seasonal variations of atmospheric C₂–C₇ nonmethane hydrocarbons in Tokyo

Shirai¹,

Yokouchi²,

Blake³

et al. 2007

J. Geophys. Res.

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[1] Eighteen C 2 -C 7 NMHCs (nonmethane hydrocarbons) were measured hourly during the Integrated Measurement Program for Aerosol and Oxidant Chemistry in Tokyo (IMPACT) measurement campaigns conducted in central Tokyo during four different periods (summer/autumn of 2003 and winter/summer of 2004). The ambient atmospheric concentrations of NMHCs showed an inverse correlation with wind speed and mixing height and were significantly affected by mesoscale weather conditions. The mixing ratio of isoprene tightly correlated with solar flux and temperature in summer, as it was dominantly emitted by the local vegetation. All the observed NMHCs except isoprene showed high correlation with each other in winter (r 2 > 0.5), suggesting concurrent accumulation under stagnant condition and common sources. Emission ratios were calculated on the basis of the correlation with carbon monoxide and ethyne. Compared to the typical winter NMHC composition, during summer there was a significant increase (up to 7 times higher than wintertime) of C 4 -C 5 alkanes from fuel evaporation; of C 2 -C 3 alkenes, n-hexane and benzene from chemical industry; and of toluene from local manufacturers, reflecting the temperature dependence of these evaporative emissions. In addition to the online measurements in Tokyo, canister sampling at a suburban site (Kisai) followed by multidimensional GC analyses was conducted during the summer campaign in 2004. The atmospheric concentrations of longer-lived compounds (! several days) at Kisai showed the buildup under sea breeze circulation. The average ambient concentration of toluene was 2 times higher than that in central Tokyo, likely because of substantial emissions from local industries as reported in the prefectural statistics.

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Section: Resultsmentioning

confidence: 99%

Seasonal variations of atmospheric C₂–C₇ nonmethane hydrocarbons in Tokyo

Shirai¹,

Yokouchi²,

Blake³

et al. 2007

J. Geophys. Res.

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“…This, along with the relatively constant emissions, greatly simplifies the interpretation of their diurnal cycles and leaves the meteorology to be the only important factor controlling the diurnal cycles of ethane and propane. The meteorological effect of nocturnal inversion caused by radiational cooling is thought to be the dominant force to modulate the concentrations of long-lived species (Wang et al, 2001). The rapid radiation of heat from the ground at night and early morning develops a temperature inversion near the surface enhancing the concentration of gaseous pollutants near the ground.…”

Section: Resultsmentioning

confidence: 99%

Diurnal and seasonal cycles of ozone precursors observed from continuous measurement at an urban site in Taiwan

Yang

Ting

WANG

et al. 2005

Atmospheric Environment

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Hourly measurement of 56 ozone precursors was conducted by a monitoring station located in a metropolitan area in central Taiwan. After nearly a year of continuous operation at this urban site, both diurnal and seasonal cycles of nonmethane hydrocarbons (NMHCs) were clearly observed, which were caused by the interplay between source, chemical loss, and meteorology. Selected species representing three different types of major sources, namely, the household fuel leakage, vehicular exhaust and gasoline evaporation, as well as biogenic emissions exhibit dramatic diurnal or seasonal cycles with each displaying its own unique characteristics.Ethane and propane, largely originated from leakage of natural gas or liquefied petroleum gases (LPG), showed concentrations elevating throughout the night and early morning, but began to decrease toward noon as the nocturnal temperature inversion elevated. Because of the lower chemical reactivity and somewhat more constant emissions than other measured target compounds, their diurnal cycles were presumably the direct reflection of the mixing height over the metropolitan area.For compounds originating from vehicular plus evaporative emissions such as benzene, which accounts for most of the monitored compounds, their diurnal cycles were also largely controlled by the variation in the height of temperature inversion.Of all the 56 species monitored, isoprene, an abundant biogenic species largely released by plants, showed distinct diurnal and seasonal cycles different from the other measured NMHCs. Its concentration usually peaked at noon in summer and fell when temperature and solar radiation reached their maximum levels, demonstrating the close relationship of isoprene with photosynthesis.Seasonal variation was also clearly observed for the other NMHCs quantified. With the exception of isoprene, most species show higher average concentration in winter and lower average concentration in summer with the fall values being the intermediate, which presumably is caused by both the seasonal variation in HO abundance and the height of the temperature inversion.

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Diurnal and seasonal cycles of ozone precursors observed from continuous measurement at an urban site in Taiwan

Yang

Ting

Wang

et al. 2005

Atmospheric Environment

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Construction of a low-cost automated chromatographic system for the measurement of ambient methane

Cited by 7 publications

References 15 publications

Seasonal variations of atmospheric C₂–C₇ nonmethane hydrocarbons in Tokyo

Seasonal variations of atmospheric C₂–C₇ nonmethane hydrocarbons in Tokyo

Diurnal and seasonal cycles of ozone precursors observed from continuous measurement at an urban site in Taiwan

Diurnal and seasonal cycles of ozone precursors observed from continuous measurement at an urban site in Taiwan

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Construction of a low-cost automated chromatographic system for the measurement of ambient methane

Cited by 7 publications

References 15 publications

Seasonal variations of atmospheric C2–C7 nonmethane hydrocarbons in Tokyo

Seasonal variations of atmospheric C2–C7 nonmethane hydrocarbons in Tokyo

Diurnal and seasonal cycles of ozone precursors observed from continuous measurement at an urban site in Taiwan

Diurnal and seasonal cycles of ozone precursors observed from continuous measurement at an urban site in Taiwan

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Seasonal variations of atmospheric C₂–C₇ nonmethane hydrocarbons in Tokyo

Seasonal variations of atmospheric C₂–C₇ nonmethane hydrocarbons in Tokyo