Characteristics of summertime ambient VOCs and their contributions to O3 and SOA formation in a suburban area of Nanjing, China

Mozaffar, Ahsan; Zhang, Yanlin; Fan, Mei-Yi; Cao, Fang; Lin, Yu‐Chi

doi:10.1016/j.atmosres.2020.104923

Cited by 92 publications

(33 citation statements)

References 76 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…IVOCs, n-alkanes, b-alkanes, and R-UCM had two peaks at 6:00 to 8:00 in the morning and 18:00 to 21:00 in the afternoon, corresponding to the morning and evening rush hours of vehicles. This was also consistent with the diurnal variation of the concentration of VOCs and NO 2 in the regional atmosphere, which showed "bimodal" distributions [34][35][36], indicating that vehicular emissions were a non-negligible emission source. Furthermore, since the sampling site is close to the national highway, vehicle emissions during the morning and evening exhibited more significant contributions to IVOCs.…”

Section: Sources Of Ivocssupporting

confidence: 85%

“…Considering that the measured emission characteristics of combustion sources in the field were much closer to real combustion, the n-alkanes/b-alkanes ratio from field measurements was used for comparison. The ratios of n-alkanes/b-alkanes in P1 and P2 were 0.32 ± 0.03 and 0.37 ± 0.04, respectively, which were significantly higher than the ratios of BB in the laboratory simulated by Zhao et al [16] and GV emission by Lu et al [34]; however, they were lower than the field-measured values of GV and ethanol-gasoline vehicles (EGV) and close to the field-measured values of BB, CC, and DV. In short, this indicated that IVOCs during haze episodes might be influenced by complex contribution sources, such as the mixture of BB, CC, GV, and DV.…”

Section: Sources Of Ivocsmentioning

confidence: 59%

See 1 more Smart Citation

Chemical Characterization, Source, and SOA Production of Intermediate Volatile Organic Compounds during Haze Episodes in North China

et al. 2021

View full text Add to dashboard Cite

The growth of secondary organic aerosols (SOA) is a vital cause of the outbreaks of winter haze in North China. Intermediate volatile organic compounds (IVOCs) are important precursors of SOA. Therefore, the chemical characteristics, source, and SOA production of IVOCs during haze episodes have attracted much attention. Hourly time resolution IVOC samples during two haze episodes collected in Hebei Province in North China were analyzed in this study. Results showed that: (1) the concentration of IVOCs measured was within the range of 11.3~85.1 μg·cm−3 during haze episodes, with normal alkanes (n-alkanes), polycyclic aromatic hydrocarbons (PAHs), branched alkanes (b-alkanes), and the residue unresolved complex mixture (R-UCM) accounting for 8.6 ± 2.3%, 6.8 ± 2.2%, 24.1 ± 3.8%, and 60.5 ± 6.5% of IVOCs, respectively. NC12-nC15 in n-alkanes, naphthalene and its alkyl substitutes in PAHs, b-alkanes in B12–B16 bins, and R-UCM in B12–B16 bins are the main components, accounting for 87.0 ± 0.2%, 87.6 ± 2.9%, 85.9 ± 5.4%, 74.0 ± 8.3%, respectively. (2) Based on the component characteristics of IVOCs and the ratios of n-alkanes/b-alkanes in emission sources and the hourly variation of IVOCs during haze episodes, coal combustion (CC), biomass burning (BB), gasoline vehicles (GV), and diesel vehicles (DV)were identified as important emission sources of IVOCs in Hebei Province. (3) During haze episodes, temporal variation of the estimated SOA production based on different methods (such as IVOCs concentration, OC/ECmin tracer, and the PMF model) were similar; however, the absolute values were different. This difference may be due to the transformation of IVOCs to SOA affected by various factors such as SOA production from different IVOC components, meteorological conditions, atmospheric oxidation, etc.

show abstract

Section: Sources Of Ivocssupporting

confidence: 85%

Section: Sources Of Ivocsmentioning

confidence: 59%

Chemical Characterization, Source, and SOA Production of Intermediate Volatile Organic Compounds during Haze Episodes in North China

et al. 2021

View full text Add to dashboard Cite

show abstract

“…Such results can seem strange especially that the NO 2 which is the precursor of O 3 has decreased over Cairo and Alexandria by 13% and 9%, respectively in April and decreased by higher values in March. However, such inconsistent relation between the NO 2 and O 3 concentrations has been previously observed in a lot of previous research work” ( Qin et al, 2004 ; Lin et al, 2005 ; Jiménez et al, 2005 ; Blanchard et al, 2008 ; Schipa et al, 2009 ; Castell et al, 2010 ; Wolff et al, 2013 ; Adame et al, 2014 ; Shen et al, 2014 ; Diéguez et al, 2014 ; Xie et al, 2016 ; Silva et al, 2018 ; Zou et al, 2019 ; Ezimand and Kakroodi, 2019 ; Tang et al, 2020 ; Soares et al, 2020 ; Liao et al, 2020 ; Mozaffar et al, 2020 ; Fang et al, 2020 ; Barcelo, 2020 ). In addition, several researchers have recently reported that O 3 levels increased in some cities during COVID-19 lockdown in complete contrast to the NO 2 concentrations ( Sicard et al, 2020 ; Siciliano et al, 2020 ; Tobías et al, 2020 ).…”

Section: Resultsmentioning

confidence: 87%

The impact of COVID 19 on air pollution levels and other environmental indicators - A case study of Egypt

Mostafa

Gamal

Wafiq

2021

Journal of Environmental Management

124

View full text Add to dashboard Cite

The outbreak of coronavirus disease (COVID-19) not only affected health and economics, but also its effect extended to include other aspects, such as the environment. Using Egypt as a case study, this paper presents the impact of COVID-19 pandemic on air pollution levels by studying nitrogen dioxide (NO 2 ), ozone (O 3 ), particulate matter represented in absorbing aerosol index (AAI), carbon monoxide (CO), and greenhouse gas (GHG) emissions. The paper also highlights the impact of COVID-19 pandemic on other environmental indicators including environmental noise, medical and municipal solid wastes. The paper presents the Egyptian COVID-19 story from its different angles including the development of confirmed COVID-19 cases, containment measures from the government, the impact on the country’s economy and the national energy consumption so as to effectively evaluate the effect on both the air pollution levels and the other studied environmental indicators. For the other environmental indicators, a strong link was observed between COVID-19 lockdown and the reduction in environmental noise, beaches, surface and groundwater pollution. For environmental noise, this has been confirmed by officially governmental announcements which reported that the level of environmental noise in Egypt was reduced by about 75% during the lockdown period. On the other hand, there are some negative effects, including an increase in medical solid waste (from 70 to 300 ton/day), municipal solid waste, as well as a less efficient solid waste recycling process. For air pollution levels, the data were obtained from National Aeronautics and Space Administration (NASA) and European Space Agency satellite data sets. The data for the lockdown period in 2020 have been extracted and compared to the corresponding months in the selected baseline period (2015-2019) to identify the effect that the lockdown period had on the air pollution levels in Egypt with focus on Cairo and Alexandria governorates. It was found that the AAI decreased by about 30%, the NO 2 decreased by 15 and 33% over Cairo and Alexandria governorates, respectively, and that the CO decreased by about 5% over both governorates. In addition, the GHG emissions in Egypt were reduced by at least 4% during the pandemic. In contrast, ozone levels increased by about 2% over Cairo and Alexandria governorates. It can be concluded that the implemented containment measures during COVID-19 pandemic had resulted in both positive and negative environmental impacts. The positive environmental impacts are not sustainable and deterioration on them is expected to occur after the lockdown as it was before the pandemic. Therefore, stricter laws must be enacted to protect the environment in Egypt.

show abstract

“…According to the basic composition of VOCs and their classification ( Mozaffar et al, 2020 ; Huang et al, 2020b ), we divided VOCs into alkanes, alkenes, alkynes, aromatic hydrocarbons, halogenated hydrocarbons, and oxygenated organics; their average January–April concentrations in Wuhan in 2019 and 2020 are shown in Fig. 6 .…”

Section: Resultsmentioning

confidence: 99%

Air quality characteristics in Wuhan (China) during the 2020 COVID-19 pandemic

Chen

Wang

et al. 2021

Environmental Research

View full text Add to dashboard Cite

Understanding the relationship between air quality, pollution emission control measures, and meteorological conditions is important for developing effective air quality improvement policies. In this study, we used pollution monitoring and meteorological data from January to May 2020 to analyze the air quality characteristics during the COVID-19 lockdown in Wuhan, which lasted from January 23 to April 8, 2020. Compared with the same period in 2019, the air quality in 2020 was significantly better. The total excellent and good air quality rates increased by 17.58%–90.08% in 2020; concentrations of NO 2 , particulate matter with a diameter <10 μm (PM 10 ) and <2.5 μm (PM 2.5 ), and total volatile organic compounds (TVOCs) also decreased by 38.23%, 30.25%, 32.92%, and 39.80%, respectively. Moreover, the number of days with NO 2 , PM 10 , and PM 2.5 as the primary pollutants decreased by approximately 10%, 9%, and 15%, respectively. We compared the wind direction, wind speed, temperature, and relative humidity in January–April 2020, 2019, 2018, and 2017 and found no obvious correlation between meteorological factors and improved air quality during the 2020 lockdown. The implementation of strict lockdown measures, such as home quarantining, traffic restrictions, and non-essential enterprise shutdowns, was the dominant cause for the substantial air quality improvement during the 2020 COVID-19 lockdown in Wuhan.

show abstract

Characteristics of summertime ambient VOCs and their contributions to O3 and SOA formation in a suburban area of Nanjing, China

Cited by 92 publications

References 76 publications

Chemical Characterization, Source, and SOA Production of Intermediate Volatile Organic Compounds during Haze Episodes in North China

Chemical Characterization, Source, and SOA Production of Intermediate Volatile Organic Compounds during Haze Episodes in North China

The impact of COVID 19 on air pollution levels and other environmental indicators - A case study of Egypt

Air quality characteristics in Wuhan (China) during the 2020 COVID-19 pandemic

Contact Info

Product

Resources

About