The vertical distributions of VOCs in the atmosphere of Beijing in autumn

Mao, Ting; Wang, Yuesi; Jie, Jiang; Wu, Fuzhong; Wang, Mingxing

doi:10.1016/j.scitotenv.2007.08.035

Cited by 65 publications

(14 citation statements)

References 34 publications

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“…Toluene and benzene are emitted by automobiles in a ratio of around 2:1 (Staehelin et al 1998;Conner et al 1995), therefore, the maximum toluene/benzene ratio (T/B) will be 2 if the traffic emission is the dominant source (Liu et al 2008;Ting et al 2008). None of the zones showed T/B close to 2.0, however, the ratio in the urban zone was the highest (1.13-1.29) suggesting that the transport influence in the urban zone is the largest in comparison with the other zones (0.50-0.81) (Fig.…”

Section: Btex Characteristic Ratiosmentioning

confidence: 99%

“…The benzene-to-toluene (B/T) ratio is a reverse value of T/B ratio, but it a commonly used as a tracer to predict long-range transport of pollutants (Srivastava et al 2005) and as an indicator of the photochemical age of the air (Ting et al 2008). This is due to the fact that toluene has a much shorter lifetime than benzene (Singh and Zimmermon 1998; Table 3) and during transport toluene will reduce more than benzene because it undergoes photochemical reactions more easily (Prinn et al 1987).…”

Section: Btex Characteristic Ratiosmentioning

confidence: 99%

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Atmospheric BTEX concentrations in the vicinity of the crude oil refinery of the Baltic region

Baltrėnas

Baltrėnaitė

Šerevičienė

et al. 2011

Environ Monit Assess

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Among chemical industries, petroleum refineries have been identified as large emitters of a wide variety of pollutants. Benzene, toluene, ethylbenzene, and xylene (BTEX) form an important group of aromatic volatile organic compounds (VOCs) because of their role in the troposphere chemistry and the risk posed to human health. A very large crude oil refinery of the Baltic States (200,000 bbl/day) is situated in the northern, rural part of Lithuania, 10 km from the town of Mažeikiai (Lithuania). The objectives of this study were: (1) to determine of atmospheric levels of BTEX in the region rural and urban parts at the vicinity of the crude oil refinery; and (2) to investigate the effect of meteorological parameters (wind speed, wind direction, temperature, pressure, humidity) on the concentrations measured. The averaged concentration of benzene varied from 2.12 ppbv in the rural areas to 2.75 ppbv in the urban areas where the traffic was determined to be a dominant source of BTEX emissions. Our study showed that concentration of benzene, as strictly regulated air pollutant by EU Directive 2008/50/EC, did not exceed the limit of 5 ppbv in the region in the vicinity of the crude oil refinery during the investigated period. No significant change in air quality in the vicinity of the oil refinery was discovered, however, an impact of the industry on the background air quality was detected. The T/B ratio (0.50-0.81) that was much lower than 2.0, identified other sources of pollution than traffic.

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Section: Btex Characteristic Ratiosmentioning

confidence: 99%

Section: Btex Characteristic Ratiosmentioning

confidence: 99%

Atmospheric BTEX concentrations in the vicinity of the crude oil refinery of the Baltic region

Baltrėnas

Baltrėnaitė

Šerevičienė

et al. 2011

Environ Monit Assess

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“…The Beijing 325 m meteorological tower (BMT) is a unique platform for measuring aerosol and gaseous species at various heights in Beijing megacity. Moreover, this platform is beneficial for studying the interactions of the lower boundary layer (< 300 m) and air pollution, particularly during autumn and winter when the nocturnal planetary boundary height is often below 300 m (Ting et al, 2008;. Based on the BMT measurements, Sun et al (2009 reported that the SO 2 concentration reached its maximal value at 50 m during heating periods, whereas PM 2.5 showed a "higher top and lower bottom" vertical pattern due to the inversions of temperature (T ) and relative humidity (RH) during summer hazy days.…”

mentioning

confidence: 99%

Characteristics and sources of submicron aerosols above the urban canopy (260 m) in Beijing, China, during the 2014 APEC summit

Chen

Sun

et al. 2015

Atmos. Chem. Phys.

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Abstract. The megacity of Beijing has experienced frequent severe fine particle pollution during the last decade. Although the sources and formation mechanisms of aerosol particles have been extensively investigated on the basis of ground measurements, real-time characterization of aerosol particle composition and sources above the urban canopy in Beijing is rare. In this study, we conducted real-time measurements of non-refractory submicron aerosol (NR-PM 1 ) composition at 260 m at the Beijing 325 m meteorological tower (BMT) from 10 October to 12 November 2014, by using an aerosol chemical speciation monitor (ACSM) along with synchronous measurements of size-resolved NR-PM 1 composition near ground level using a high-resolution timeof-flight aerosol mass spectrometer (HR-ToF-AMS). The NR-PM 1 composition above the urban canopy was dominated by organics (46 %), followed by nitrate (27 %) and sulfate (13 %). The high contribution of nitrate and high NO − 3 / SO 2− 4 mass ratios illustrates an important role of nitrate in particulate matter (PM) pollution during the study period. The organic aerosol (OA) was mainly composed of secondary OA (SOA), accounting for 61 % on an average. Different from that measured at the ground site, primary OA (POA) correlated moderately with SOA, likely suggesting a high contribution from regional transport above the urban canopy. The Asia-Pacific Economic Cooperation (APEC) summit with strict emission controls provides a unique opportunity to study the impacts of emission controls on aerosol chemistry. All aerosol species were shown to have significant decreases of 40-80 % during APEC from those measured before APEC, suggesting that emission controls over regional scales substantially reduced PM levels. However, the bulk aerosol composition was relatively similar before and during APEC as a result of synergetic controls of aerosol precursors. In addition to emission controls, the routine circulations of mountain-valley breezes were also found to play an important role in alleviating PM levels and achieving the "APEC blue" effect. The evolution of vertical differences between 260 m and the ground level was also investigated. Our results show complex vertical differences during the formation and evolution of severe haze episodes that are closely related to aerosol sources and boundary-layer dynamics.

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“…as it belongs to chlorinated VOCs, it is often used as model molecule to investigate the behavior of this class of pollutants [52]. Methanol is a polar alcohol which can cause damage to several organs, particularly to the optic nerve.…”

Section: Introductionmentioning

confidence: 99%

Absorption and photocatalytic degradation of VOCs by perfluorinated ionomeric coating with TiO2 nanopowders for air purification

Sansotera

Kheyli

Baggioli

et al. 2019

Chemical Engineering Journal

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In this work, we propose a transparent multilayered perfluoropolymeric coating as immobilization method for TiO2 nanoparticles, and evaluate its suitability in the gas phase photocatalytic degradation of six different volatile organic compounds. The coating was made of a layer of TiO2containing perfluorosulfonic acid polymer on a layer of perfluorinated amorphous polymer. The chemical stability of perfluoropolymeric materials to UV radiation and UV-activated TiO2 overcomes the possible degradation of the polymeric immobilization system which is typical of more traditional polymeric coatings. Moreover, the TiO2-containing ionomeric perfluorosulfonic layer worked as selective membrane for pollutants absorption and catalyst preservation, depending on the interactions between the superacidic polar heads of the ionomer and the pollutants, in particular those capable of hydrogen bonding. Gas-phase photocatalytic degradation tests were performed using pentane, methanol, 2-propanol, toluene, dichloromethane and pyridine as reference volatile organic pollutants, thus ranging on different polarity properties. Results indicate performances comparable to other approaches reported in the literature and show a strong influence of both atmospheric conditions (namely, humidity) and pollutant nature-polarity, proticity-on the actual kinetics of photodegradation, also depending on the interactions regulating the affinity between the ionomeric layer of the coating and pollutants. The high potential of the coating in the photodegradation was confirmed by the observed values of the photoabatement rates: all approximatively above 10-5 s-1 and maximum for alcohols (1.4 × 10-4 and 1.7 × 10-4 s-1 in dry and humid conditions, respectively).

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The vertical distributions of VOCs in the atmosphere of Beijing in autumn

Cited by 65 publications

References 34 publications

Atmospheric BTEX concentrations in the vicinity of the crude oil refinery of the Baltic region

Atmospheric BTEX concentrations in the vicinity of the crude oil refinery of the Baltic region

Characteristics and sources of submicron aerosols above the urban canopy (260 m) in Beijing, China, during the 2014 APEC summit

Absorption and photocatalytic degradation of VOCs by perfluorinated ionomeric coating with TiO2 nanopowders for air purification

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