scholarly journals Water-Induced Inverse Correlation between Temperature and Flux Changes in Vertical Vapor-Phase Diffusive Transport of Volatile Organic Compounds in Near-Surface Soil Environments

2021 ◽  
Vol 11 (8) ◽  
pp. 3489
Author(s):  
Asma Akter Parlin ◽  
Noriaki Watanabe ◽  
Kengo Nakamura ◽  
Mizuki Yamada ◽  
Jiajie Wang ◽  
...  
Keyword(s):  
Grain Size ◽  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Vapor Phase ◽  
Contaminated Soils ◽  
Inverse Correlation ◽  
Diffusive Transport ◽  
Near Surface ◽  
Temperature Changes ◽  
Volatile Organic

Volatile organic compounds (VOCs) in contaminated soils have been investigated in near-surface environments to describe their transport behaviors and the resultant impacts of vapor intrusion into buildings. Prior studies have suggested that temperature changes significantly influence such transport behaviors in near-surface soils; however, the nature of these influences and their mechanisms have remained unclear. This is because an inverse correlation between the in situ temperature and VOC flux changes has been suggested but has not been experimentally investigated or demonstrated. Herein, we show the results of a set of experiments on the vertical and upward vapor-phase diffusive transport of benzene in sandy soils for different sand grain size and water content combinations under sinusoidal temperature changes between 20 and 30 °C. Under all experimental conditions, changes in the flux from the soil surface correlated with temperature changes, whereas changes in the flux into the overlying soil showed inverse correlations. Concurrent monitoring of the relative humidity revealed that an inverse correlation was exhibited in response to the condensation and volatilization of water. Moreover, the intensity of the inverse correlation was independent of grain size but was larger at higher water contents. Overall, water in soil may induce an inverse correlation.

scholarly journals Water-Enhanced Flux Changes under Dynamic Temperatures in the Vertical Vapor-Phase Diffusive Transport of Volatile Organic Compounds in Near-Surface Soil Environments

2021 ◽  
Vol 13 (12) ◽  
pp. 6570
Author(s):  
Asma Akter Parlin ◽  
Monami Kondo ◽  
Noriaki Watanabe ◽  
Kengo Nakamura ◽  
Mizuki Yamada ◽  
...  
Keyword(s):  
Air Quality ◽  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Vapor Phase ◽  
Inverse Correlation ◽  
Diffusive Transport ◽  
Near Surface ◽  
Voc Emissions ◽  
Transport Behavior ◽  
Volatile Organic

The quantitative understanding of the transport behavior of volatile organic compounds (VOCs) in near-surface soils is highly important in light of the potential impacts of soil VOC emissions on the air quality and climate. Previous studies have suggested that temperature changes affect the transport behavior; however, the effects are not well understood. Indeed, much larger changes in the VOC flux under in situ dynamic temperatures than those expected from the temperature dependence of the diffusion coefficients of VOCs in the air have been suggested but rarely investigated experimentally. Here, we present the results of a set of experiments on the upward vertical vapor-phase diffusive transport of benzene and trichloroethylene (TCE) in sandy soils with water contents ranging from an air-dried value to 10 wt% during sinusoidal temperature variation between 20 and 30 °C. In all experiments, the flux from the soil surface was correlated with the temperature, as expected. However, the changes in flux under wet conditions were unexpectedly large and increased with increasing water content; they were also larger for TCE, the volatility of which depended more strongly on the temperature. Additionally, the larger flux changes were accompanied by a recently discovered water-induced inverse correlation between temperature and flux into the overlying soil. These results demonstrated that the flux changes of VOCs under dynamic temperatures could be increased by volatilization-dissolution interactions of VOCs with water. Future extensive studies on this newly discovered phenomenon would contribute to a better understanding of the impacts of soil VOC emissions on the air quality and climate.

scholarly journals Sensitivity of biogenic volatile organic compounds to land surface parameterizations and vegetation distributions in California

2016 ◽  
Vol 9 (5) ◽  
pp. 1959-1976 ◽  
Author(s):  
Chun Zhao ◽  
Maoyi Huang ◽  
Jerome D. Fast ◽  
Larry K. Berg ◽  
Yun Qian ◽  
...  
Keyword(s):  
Air Quality ◽  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Land Surface ◽  
Aerosol Formation ◽  
Biogenic Volatile Organic Compounds ◽  
Vegetation Map ◽  
Near Surface ◽  
Volatile Organic ◽  
The Impact

Abstract. Current climate models still have large uncertainties in estimating biogenic trace gases, which can significantly affect atmospheric chemistry and secondary aerosol formation that ultimately influences air quality and aerosol radiative forcing. These uncertainties result from many factors, including uncertainties in land surface processes and specification of vegetation types, both of which can affect the simulated near-surface fluxes of biogenic volatile organic compounds (BVOCs). In this study, the latest version of Model of Emissions of Gases and Aerosols from Nature (MEGAN v2.1) is coupled within the land surface scheme CLM4 (Community Land Model version 4.0) in the Weather Research and Forecasting model with chemistry (WRF-Chem). In this implementation, MEGAN v2.1 shares a consistent vegetation map with CLM4 for estimating BVOC emissions. This is unlike MEGAN v2.0 in the public version of WRF-Chem that uses a stand-alone vegetation map that differs from what is used by land surface schemes. This improved modeling framework is used to investigate the impact of two land surface schemes, CLM4 and Noah, on BVOCs and examine the sensitivity of BVOCs to vegetation distributions in California. The measurements collected during the Carbonaceous Aerosol and Radiative Effects Study (CARES) and the California Nexus of Air Quality and Climate Experiment (CalNex) conducted in June of 2010 provided an opportunity to evaluate the simulated BVOCs. Sensitivity experiments show that land surface schemes do influence the simulated BVOCs, but the impact is much smaller than that of vegetation distributions. This study indicates that more effort is needed to obtain the most appropriate and accurate land cover data sets for climate and air quality models in terms of simulating BVOCs, oxidant chemistry and, consequently, secondary organic aerosol formation.

scholarly journals Petrochemical and Industrial Sources of Volatile Organic Compounds Analyzed via Regional Wind-Driven Network in Shanghai

Atmosphere ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 760 ◽  
Author(s):  
Wanyi Qiu ◽  
Shule Li ◽  
Yuhan Liu ◽  
Keding Lu
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Surface Ozone ◽  
Industrial Area ◽  
Ozone Pollution ◽  
Regional Network ◽  
Local Circulation ◽  
Near Surface ◽  
Secondary Pollutants ◽  
Volatile Organic

Due to the development of industrialization and urbanization, secondary pollution is becoming increasingly serious in the Yangtze River Delta. Volatile organic compounds (VOCs) are key precursors of the near-surface ozone, secondary organic aerosol (SOA), and other secondary pollutants. In this study, we chose a serious ozone pollution period (01 May–31 July 2017) in Jinshan, which is a petrochemical and industrial area in Shanghai. We explored the VOCs distribution characteristics and contribution to secondary pollutants via constructing a regional network based on wind patterns. We determined that dense pollutants were accumulated at adjacent sites under local circulation (LC), and pollution from petrochemical discharge was more serious than industry for all sites under southeast (SE) wind. We also found that cyclopentane, o-xylene, m/p-xylene, 1-3-butadiene, and 1-hexene were priority-controlled species as they were most vital to form secondary pollutants. This study proves that regional network analysis can be successfully applied to explore pollution characteristics and regional secondary pollutants formation.

A robust two-dimensional zirconium-based luminescent coordination polymer built on a V-shaped dicarboxylate ligand for vapor phase sensing of volatile organic compounds

2018 ◽  
Vol 54 (58) ◽  
pp. 8088-8091 ◽  
Author(s):  
Pei-Yao Du ◽  
William P. Lustig ◽  
Simon J. Teat ◽  
Wen Gu ◽  
Xin Liu ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Coordination Polymer ◽  
Organic Compounds ◽  
Vapor Phase ◽  
Two Dimensional ◽  
Volatile Organic ◽  
Dicarboxylate Ligand

We report herein a new two-dimensional zirconium-based luminescent coordination polymer exhibiting selective fluorescence responses towards a variety of volatile organic compounds upon exposure in the vapor phase.

Predicting the Effect of Moisture on Vapor-Phase Sorption of Volatile Organic Compounds to Soils

1996 ◽  
Vol 30 (4) ◽  
pp. 1081-1091 ◽  
Author(s):  
David R. Unger ◽  
Thientu T. Lam ◽  
Charles E. Schaefer ◽  
David S. Kosson
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Vapor Phase ◽  
Volatile Organic ◽  
Effect Of Moisture
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