Characteristics of one-year observation of VOCs, NOx, and O3 at an urban site in Wuhan, China

Yang, Yichang; Liu, Xingang; Zheng, Jun; Tan, Qinwen; Feng, Miao; Yu, Qian; An, Junling; Cheng, Ning

doi:10.1016/j.jes.2018.12.002

Cited by 76 publications

(37 citation statements)

References 35 publications

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“…The high concentration of acetone in our research was similar to the previous studies in Beijing (8.00 ppbv), Guangzhou (6.41 ppbv), and the selected public places of Hangzhou (7.11 ppbv) [30][31][32]. Table S3 shows the concentrations of main VOCs observed in other cities (Beijing, Shanghai, Guangzhou, and Wuhan) as well as Hangzhou [33][34][35][36]. The comparison indicated that concentrations of TVOCs in Hangzhou were similar to Shanghai and Wuhan, but much lower than Beijing and Guangzhou.…”

Section: Overall Meteorology and Pollutantssupporting

confidence: 87%

“…E t h a n e P r o p a n e n -B u t a n e n -P e n t a n e I s o b u t a n e I s o p e n t a n e n -H e p t a n e n -H e x a n e n - Table S3 shows the concentrations of main VOCs observed in other cities (Beijing, Shanghai, Guangzhou, and Wuhan) as well as Hangzhou [33][34][35][36]. The comparison indicated that concentrations of TVOCs in Hangzhou were similar to Shanghai and Wuhan, but much lower than Beijing and Guangzhou.…”

Section: Hp (A)mentioning

confidence: 99%

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Source Apportionment of Volatile Organic Compounds (VOCs) during Ozone Polluted Days in Hangzhou, China

Han

Chen

et al. 2019

Atmosphere

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A field sampling campaign of volatile organic compounds (VOCs) was conducted during ozone polluted days at three sites of botanic gardens (HP), industrial areas (XS), and traffic residential mixed areas (ZH) in Hangzhou. The sampling was performed using stainless steel canisters from 6:00 to 20:00 synchronously with a time interval of 2 h on 17 May, 26 June, 20 July, 24 August, and 26 September 2018. A total of 107 species of VOCs for each sample were quantified using two standard gases with a pre-concentrator coupled by GC/MS. The Positive Matrix Factorization (PMF) model was used to identify the major VOC sources and assess their contribution to VOC concentrations. The effects of VOCs on O3 formation were investigated, based on propylene-equivalent concentrations (Prop-E), ozone formation potential (OFP), and Smog Production Model (SPM). It was found that the concentration of ozone during the sampling days tended to be highest in the downwind area while the concentrations of VOCs and NO2 in HP were rather low. The most reactive species were isoprene, ethylene, m-xylene, toluene, and propylene. The average total VOC volume mixing ratios in HP, XS, and ZH were 32.00, 36.63, and 50.34 ppbv, respectively. Bimodal profiles of propane and n-butane were exhibited in ZH while unimodal diurnal variation of isoprene was performed in HP. Liquefied petroleum gas/natural gas (LPG/NG) usage, aged background, and secondary source were identified as the major contributors to total VOCs in Hangzhou, accounting for 19.65%, 15.53%, and 18.93%, respectively.

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Section: Overall Meteorology and Pollutantssupporting

confidence: 87%

Section: Hp (A)mentioning

confidence: 99%

Source Apportionment of Volatile Organic Compounds (VOCs) during Ozone Polluted Days in Hangzhou, China

Han

Chen

et al. 2019

Atmosphere

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“…The correlation becomes positive when the values of NO x are above 80 μg/m 3 . This may be due to faster photochemical dissociation and transport of NO x at the same instant (Yang et al 2019). The correlation between NO x and O 3 is stronger during monsoon season and during the nighttime when the influence of solar irradiance and temperature is less, as illustrated in Figure 9f.…”

Section: Correlation and Regression Analyses Of O 3 With Temperaturementioning

confidence: 93%

Assessment of tropospheric ozone at an industrial site of Chennai megacity

Mohan

Saranya

2019

Journal of the Air & Waste Management Association

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This paper presents the temporal variation in surface-level ozone (O 3) measured at Gummidipoondi near Chennai, Tamilnadu. The site chosen for the present study has high potential for ozone generation sources, such as vehicular traffic and industrial activities. The site is also located near a hazardous waste management facility. The key sources of nitrogen oxides (NO x), which are considered to be an important precursor of O 3 , include hazardous waste incineration, trucks bringing the hazardous wastes, and vehicles plying on the nearby National Highway 16 (NH 16). The measurements clearly showed diurnal variation, with maximum values observed during the noon hours and minimum values observed when solar radiation was less. The data showed a marked seasonal variation in O 3 , with the highest hourly average O 3 concentration (497.2 µg/m 3) in the summer season. Consequently, in order to identify the long-range transport sources adding to the increased O 3 levels, backward trajectories were computed using the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model. It was found that the polluted air mass originated from the Southeast Asian region and the Indo-Gangetic Plain. The polluted air mass, which advected large amounts of carbon monoxide (CO) plumes, was analyzed using the Measurement of Pollution in the Troposphere (MOPITT) retrievals. The correlations of O 3 with temperature (r = 0.746; P < 0.01) and solar radiation (r = 0.751; P < 0.01) were strongly positive, and that with NO x was found to be negative. Stronger correlation of O 3 with NO x was observed during pre-monsoon months (r = 0.627; P < 0.01) and following hours of photochemical reactions. There were substantial differences in concentrations between weekdays and weekends, with higher nitric oxide (NO) and nitrogen dioxide (NO 2), but lower O 3 , concentrations on weekdays. A substantial weekday-weekend difference in O 3 , which was higher on weekends, appears to be attributable to lower daytime traffic activity and hence reduced emissions of NO x to a "NO x-saturated" atmosphere. Implications: The assessment of ground-level ozone in an industrial area with hazardous waste management facility is very important, as there is high possibility for more generation of tropospheric ozone. Since the location of the study area is coastal, wind plays a major role in O 3 transportation; hence, the effects of wind speed and wind direction have been studied in different seasons. When compared with the other studies carried out in different places across India, the present study area has recorded much greater O 3 mixing ratio. This study can be useful for setting up control strategies in such industrial areas.

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“…The time resolution was 1 h, and ambient air was sampled during the first 5 min of each hour for both channels with a flow of 300 mL/min. The uncertainties for VOC measurements by GC-MS/FID are estimated to be 15 %-20 % (Wang et al, 2014b;Yuan et al, 2012a). In addition to PTR-ToF-MS, formaldehyde was also measured by a custom-built online instrument based on the Hantzsch reaction and absorption photometry from 16 October to 20 November 2018.…”

Section: Other Measurementsmentioning

confidence: 99%

Measurement report: Important contributions of oxygenated compounds to emissions and chemistry of volatile organic compounds in urban air

Wang

et al. 2020

Atmos. Chem. Phys.

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Abstract. Volatile organic compounds (VOCs) play important roles in the tropospheric atmosphere. In this study, VOCs were measured at an urban site in Guangzhou, one of the megacities in the Pearl River Delta (PRD), using a gas chromatograph–mass spectrometer/flame ionization detection (GC–MS/FID) and a proton transfer reaction time-of-flight mass spectrometer (PTR-ToF-MS). Diurnal profile analyses show that stronger chemical removal by OH radicals for more reactive hydrocarbons occurs during the daytime, which is used to estimate the daytime average OH radical concentration. In comparison, diurnal profiles of oxygenated volatile organic compounds (OVOCs) indicate evidence of contributions from secondary formation. Detailed source analyses of OVOCs, using a photochemical age-based parameterization method, suggest important contributions from both primary emissions and secondary formation for measured OVOCs. During the campaign, around 1700 ions were detected in PTR-ToF-MS mass spectra, among which there were 462 ions with noticeable concentrations. VOC signals from these ions are quantified based on the sensitivities of available VOC species. OVOC-related ions dominated PTR-ToF-MS mass spectra, with an average contribution of 73 % ± 9 %. Combining measurements from PTR-ToF-MS and GC–MS/FID, OVOCs contribute 57 % ± 10 % to the total concentration of VOCs. Using concurrent measurements of OH reactivity, OVOCs measured by PTR-ToF-MS contribute greatly to the OH reactivity (19 % ± 10 %). In comparison, hydrocarbons account for 21 % ± 11 % of OH reactivity. Adding up the contributions from inorganic gases (48 % ± 15 %), ∼ 11 % (range of 0 %–19 %) of the OH reactivity remains `missing”, which is well within the combined uncertainties between the measured and calculated OH reactivity. Our results demonstrate the important roles of OVOCs in the emission and evolution budget of VOCs in the urban atmosphere.

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Characteristics of one-year observation of VOCs, NOx, and O3 at an urban site in Wuhan, China

Cited by 76 publications

References 35 publications

Source Apportionment of Volatile Organic Compounds (VOCs) during Ozone Polluted Days in Hangzhou, China

Source Apportionment of Volatile Organic Compounds (VOCs) during Ozone Polluted Days in Hangzhou, China

Assessment of tropospheric ozone at an industrial site of Chennai megacity

Measurement report: Important contributions of oxygenated compounds to emissions and chemistry of volatile organic compounds in urban air

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