scholarly journals Sources of volatile organic compounds and policy implications for regional ozone pollution control in an urban location of Nanjing, East China

2019 ◽  
Author(s):  
Qiuyue Zhao ◽  
Jun Bi ◽  
Zhenghao Ling ◽  
Qian Liu ◽  
Guofeng Shen ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Policy Implications ◽  
Chemical Mechanism ◽  
Effective Control ◽  
Urban Site ◽  
Biogenic Emissions ◽  
Industrial Emissions ◽  
Photochemical Pollution ◽  
Volatile Organic

Abstract. Understanding the composition, temporal variability, and source apportionment of volatile organic compounds (VOCs) is necessary for determining effective control measures to minimize VOCs and its related photochemical pollution. To provide a comprehensive analysis of VOC sources and their contributions to ozone (O3) formation in the Yangtze River Delta (YRD) – a region experiencing highest rates of industrial and economic development in China, we conducted a one-year sampling exercise for the first time at an urban site in Nanjing (JAES site). Alkanes were the dominant group at the JAES site, contributing ~ 53 % to the observed total VOCs, followed by aromatics (~ 17 %), acetylene (~ 17 %), and alkenes (~ 13 %). We identified seasonal variability in TVOCs with maximum and minimum concentrations in winter and summer, respectively. A morning and evening peak and a daytime trough were identified in the diurnal VOCs patterns. We identified the source apportionments of VOCs and their contributions to photochemical O3 formation using the Positive Matrix Factorization (PMF) and observation-based model together with a Master Chemical Mechanism (MCM). The PMF model identified five dominant VOC sources, with highest contributions from diesel vehicular exhausts (34 ± 5 %), followed by gasoline vehicular exhausts (27 ± 3 %), industrial emissions (19 ± 2 %), fuel evaporation (15 ± 2 %) and biogenic emissions (4 ± 1 %). The results from the OBM-MCM model simulation inferred photochemical O3 formation to be VOC-limited at the JAES site when considering both the reactivity and abundance of the individual VOC species in each source category. Further, VOCs from vehicular and industrial emissions were found to be the dominant control on O3 formation, particularly the VOC species m,p-xylene, toluene and propene, which top priorities should be given to the alleviation of photochemical smog. However, when considering the reactivity and abundance of VOC species, the contribution of biogenic emissions to O3 pollution was significantly reduced. Our results therefore highlight the need to consider both the abundance and reactivity of individual VOC species in order to develop effective control strategies to minimize photochemical pollution in Nanjing.

scholarly journals Sources of volatile organic compounds and policy implications for regional ozone pollution control in an urban location of Nanjing, East China

2020 ◽  
Vol 20 (6) ◽  
pp. 3905-3919 ◽  
Author(s):  
Qiuyue Zhao ◽  
Jun Bi ◽  
Qian Liu ◽  
Zhenghao Ling ◽  
Guofeng Shen ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Control Measures ◽  
Policy Implications ◽  
Effective Control ◽  
Urban Site ◽  
Industrial Emissions ◽  
Photochemical Pollution ◽  
Volatile Organic ◽  
Vehicular Exhaust

Abstract. Understanding the composition, temporal variability and source apportionment of volatile organic compounds (VOCs) is necessary for determining effective control measures to minimize VOCs and their related photochemical pollution. To provide a comprehensive analysis of VOC sources and their contributions to ozone (O3) formation in the Yangtze River Delta (YRD) – a region experiencing the highest rates of industrial and economic development in China – we conducted a 1-year sampling exercise using a thermal desorption GC (gas chromatography) system for the first time at an urban site in Nanjing (JAES site). Alkanes were the dominant group at the JAES site, contributing ∼53 % to the observed total VOCs, followed by aromatics (∼17 %), acetylene (∼17 %) and alkenes (∼13 %). We identified seasonal variability in total VOCs (TVOCs) with maximum and minimum concentrations in winter and summer, respectively. Morning and evening peaks and a daytime trough were identified in the diurnal VOC patterns. We identified VOC sources using positive matrix factorization (PMF) and assessed their contributions to photochemical O3 formation by calculating the O3 formation potential (OFP) based on the mass concentrations and maximum incremental reactivities of VOCs. The PMF model identified five dominant VOC sources, with highest contributions from diesel vehicular exhaust (34±5 %), followed by gasoline vehicular exhaust (27±3 %), industrial emissions (19±2 %), fuel evaporation (15±2 %) and biogenic emissions (4±1 %). The results of the OFP calculation inferred that VOCs from industrial and vehicular emissions were found to be the dominant precursors for OFP, particularly the VOC species of xylenes, toluene and propene, and top priority should be given to these for the alleviation of photochemical smog. Our results therefore highlight that priority should be given to limited VOC sources and species for effective control of O3 formation in Nanjing.

scholarly journals Estimating the Biogenic Non-Methane Hydrocarbon Emissions over Greece

2017 ◽  
Author(s):  
Ermioni Dimitropoulou ◽  
Vassiliki D. Assimakopoulos ◽  
Kyriaki M. Fameli ◽  
Helena A. Flocas ◽  
Panagiotis Kosmopoulos ◽  
...  
Keyword(s):  
Land Use ◽  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Emission Inventory ◽  
Biogenic Emissions ◽  
Hydrocarbon Emissions ◽  
Photochemical Pollution ◽  
Radiation Data ◽  
Volatile Organic ◽  
One Year

Biogenic emissions affect the urban air quality as they are ozone and SOA precursors and should be taken into account when applying photochemical pollution models. The present study presents an estimation of the magnitude of Non-Methane Volatile Organic Compounds emissions (NMVOCs) emitted by vegetation over Greece. The methodology is based on computation performed with the aid of a Geographic Information System (GIS) and theoretical equations in order to develop an emission inventory on a 6x6  spatial resolution, in a temporal resolution of 1hr covering one year (2016). For this purpose, a variety of input data was used: improved satellite land-use data, land-use specific emission potentials, foliar biomass densities, temperature and solar radiation data. Hourly, daily and annual isoprene, monoterpenes and other volatile organic compounds (OVOCs) were estimated. In the area under study, the annual biogenic emissions were estimated up to 472 kt, consisting of 46.6% isoprene, 28% monoterpenes and 25.4% OVOCs. Results delineate an annual cycle with increasing values from March to April, while maximum emissions were observed from May to September, followed by a decrease from October to January.

scholarly journals Spatial Distribution, Source Apportionment, Ozone Formation Potential, and Health Risks of Volatile Organic Compounds over a Typical Central Plain City in China

Atmosphere ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1365
Author(s):  
Kun He ◽  
Zhenxing Shen ◽  
Jian Sun ◽  
Yali Lei ◽  
Yue Zhang ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Source Apportionment ◽  
Organic Compounds ◽  
Health Risks ◽  
Urban Areas ◽  
High Time Resolution ◽  
Ozone Formation ◽  
Industrial Site ◽  
Industrial Emissions ◽  
Volatile Organic

The profiles, contributions to ozone formation, and associated health risks of 56 volatile organic compounds (VOCs) species were investigated using high time resolution observations from photochemical assessment monitoring stations (PAMs) in Luoyang, China. The daily averaged concentration of total VOCs (TVOCs) was 21.66 ± 10.34 ppbv in urban areas, 14.45 ± 7.40 ppbv in suburbs, and 37.58 ± 13.99 ppbv in an industrial zone. Overall, the VOCs levels in these nine sites followed a decreasing sequence of alkanes > aromatics > alkenes > alkyne. Diurnal variations in VOCs exhibited two peaks at 8:00–9:00 and 19:00–20:00, with one valley at 23:00–24:00. Source apportionment indicated that vehicle and industrial emissions were the dominant sources of VOCs in urban and suburban sites. The industrial site displayed extreme levels, with contributions from petrochemical-related sources of up to 38.3%. Alkenes and aromatics displayed the highest ozone formation potentials because of their high photochemical reactivity. Cancer and noncancer risks in the industrial site were higher than those in the urban and suburban areas, and USEPA possible risk thresholds were reached in the industrial site, indicating PAMs VOC–related health problems cannot be ignored. Therefore, vehicle and industrial emissions should be prioritized when considering VOCs and O3 control strategies in Luoyang.

scholarly journals Aerosol mass yields of selected biogenic volatile organic compounds – a theoretical study with nearly explicit gas-phase chemistry

2019 ◽  
Vol 19 (22) ◽  
pp. 13741-13758
Author(s):  
Carlton Xavier ◽  
Anton Rusanen ◽  
Putian Zhou ◽  
Chen Dean ◽  
Lukas Pichelstorfer ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Gas Phase ◽  
Organic Compounds ◽  
Chemical Mechanism ◽  
Biogenic Volatile Organic Compounds ◽  
Gas Phase Chemistry ◽  
Mass Load ◽  
Volatile Organic ◽  
Phase Chemistry ◽  
Good Agreement

Abstract. In this study we modeled secondary organic aerosol (SOA) mass loadings from the oxidation (by O3, OH and NO3) of five representative biogenic volatile organic compounds (BVOCs): isoprene, endocyclic bond-containing monoterpenes (α-pinene and limonene), exocyclic double-bond compound (β-pinene) and a sesquiterpene (β-caryophyllene). The simulations were designed to replicate an idealized smog chamber and oxidative flow reactors (OFRs). The Master Chemical Mechanism (MCM) together with the peroxy radical autoxidation mechanism (PRAM) were used to simulate the gas-phase chemistry. The aim of this study was to compare the potency of MCM and MCM + PRAM in predicting SOA formation. SOA yields were in good agreement with experimental values for chamber simulations when MCM + PRAM was applied, while a stand-alone MCM underpredicted the SOA yields. Compared to experimental yields, the OFR simulations using MCM + PRAM yields were in good agreement for BVOCs oxidized by both O3 and OH. On the other hand, a stand-alone MCM underpredicted the SOA mass yields. SOA yields increased with decreasing temperatures and NO concentrations and vice versa. This highlights the limitations posed when using fixed SOA yields in a majority of global and regional models. Few compounds that play a crucial role (>95 % of mass load) in contributing to SOA mass increase (using MCM + PRAM) are identified. The results further emphasized that incorporating PRAM in conjunction with MCM does improve SOA mass yield estimation.

scholarly journals An Integrated Method for Factor Number Selection of PMF Model: Case Study on Source Apportionment of Ambient Volatile Organic Compounds in Wuhan

Atmosphere ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 390 ◽  
Author(s):  
Fenjuan Wang ◽  
Zhenyi Zhang ◽  
Costanza Acciai ◽  
Zhangxiong Zhong ◽  
Zhaokai Huang ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Source Apportionment ◽  
Correlation Coefficient ◽  
Organic Compounds ◽  
Industrial Emissions ◽  
Integrated Method ◽  
Pmf Model ◽  
Volatile Organic ◽  
Measurement Period

The positive matrix factorization (PMF) model is widely used for source apportionment of volatile organic compounds (VOCs). The question about how to select the proper number of factors, however, is rarely studied. In this study, an integrated method to determine the most appropriate number of sources was developed and its application was demonstrated by case study in Wuhan. The concentrations of 103 ambient volatile organic compounds (VOCs) were measured intensively using online gas chromatography/mass spectrometry (GC/MS) during spring 2014 in an urban residential area of Wuhan, China. During the measurement period, the average temperature was approximately 25 °C with very little domestic heating and cooling. The concentrations of the most abundant VOCs (ethane, ethylene, propane, acetylene, n-butane, benzene, and toluene) in Wuhan were comparable to other studies in urban areas in China and other countries. The newly developed integrated method to determine the most appropriate number of sources is in combination of a fixed minimum threshold value for the correlation coefficient, the average weighted correlation coefficient of each species, and the normalized minimum error. Seven sources were identified by using the integrated method, and they were vehicular emissions (45.4%), industrial emissions (22.5%), combustion of coal (14.7%), liquefied petroleum gas (LPG) (9.7%), industrial solvents (4.4%), and pesticides (3.3%) and refrigerants. The orientations of emission sources have been characterized taking into account the frequency of wind directions and contributions of sources in each wind direction for the measurement period. It has been concluded that the vehicle exhaust contribution is greater than 40% distributed in all directions, whereas industrial emissions are mainly attributed to the west southwest and south southwest.

scholarly journals A temporally and spatially resolved validation of emission inventories by measurements of ambient volatile organic compounds in Beijing, China

2014 ◽  
Vol 14 (12) ◽  
pp. 5871-5891 ◽  
Author(s):  
M. Wang ◽  
M. Shao ◽  
W. Chen ◽  
B. Yuan ◽  
S. Lu ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Measurement Data ◽  
Suburban Area ◽  
Urban Site ◽  
Emission Inventories ◽  
Relative Contribution ◽  
Volatile Organic ◽  
Current Emission ◽  
Ambient Measurements

Abstract. Understanding the sources of volatile organic compounds (VOCs) is essential for ground-level ozone and secondary organic aerosol (SOA) abatement measures. We made VOC measurements at 27 sites and online observations at an urban site in Beijing from July 2009 to January 2012. Based on these measurement data, we determined the spatial and temporal distribution of VOCs, estimated their annual emission strengths based on their emission ratios relative to carbon monoxide (CO), and quantified the relative contributions of various sources using the chemical mass balance (CMB) model. These results from ambient measurements were compared with existing emission inventories to evaluate the spatial distribution, species-specific emissions, and source structure of VOCs in Beijing. The measured VOC distributions revealed a hotspot in the southern suburban area of Beijing, whereas current emission inventories suggested that VOC emissions were concentrated in downtown areas. Compared with results derived from ambient measurements, the annual inventoried emissions of oxygenated VOC (OVOC) species and C2–C4 alkanes may be underestimated, while the emissions of styrene and 1,3-butadiene may be overestimated by current inventories. Source apportionment using the CMB model identified vehicular exhaust as the most important VOC source, with the relative contribution of 49%, in good agreement with the 40–51% estimated by emission inventories. The relative contribution of paint and solvent utilization obtained from the CMB model was 14%, significantly lower than the value of 32% reported by one existing inventory. Meanwhile, the relative contribution of liquefied petroleum gas (LPG) usage calculated using the CMB model was 6%, whereas LPG usage contribution was not reported by current emission inventories. These results suggested that VOC emission strengths in southern suburban area of Beijing, annual emissions of C2–C4 alkanes, OVOCs and some alkenes, and the contributions of solvent and paint utilization and LPG usage in current inventories all require significant revisions.

Interactions and implications of halogens and VOCs on tropospheric oxidant cycles in the remote atmosphere

2020 ◽  
Author(s):  
Eric C. Apel
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Model Development ◽  
Tropospheric Chemistry ◽  
Chemical Mechanism ◽  
Chemical Production ◽  
Four Seasons ◽  
The Pacific ◽  
Volatile Organic ◽  
Remote Troposphere

<p>Reactive halogens have wide-ranging consequences on tropospheric chemistry including ozone destruction, HOx and NOx partitioning, oxidization of volatile organic compounds (VOCs) and initiation of new particle formation. Of particular note and importance, the tropospheric Ox loss due to halogens is estimated to be between 10-20% globally, and up to 50% in some local marine environments. In this work, we include a state-of-the-art coupled halogen and VOCs chemical mechanism into the CAM-Chem global model. Complementing the model development and providing the opportunity to test the model are recent results from the NASA Atmospheric Tomography (ATom) experiment.  ATom was conducted with a heavily instrumented NASA DC-8 aircraft over the course of two and a half years, transecting the lengths of the Pacific and Atlantic Oceans during four seasons, constantly profiling from the surface (200 m) to the upper troposphere/lower stratosphere (12000 m). The ATom payload included instruments that measured both inorganic halogens and organic halogen-containing very short-lived substances (VSLS), as well as those that measured additional volatile organic compounds (VOCs), including hydrocarbons and oxygenated VOCs (OVOCs), both of which react with halogens. Modeled BrO is sensitive to the inclusion of reactions between Br and OVOCs, particularly the aldehydes, which rapidly convert Br to HBr, a far less reactive form of Br<sub>y</sub>. These reactions can have large implications in the remote troposphere where the ATom measurements have revealed significant emissions and chemical production of low molecular weight aldehydes over the remote marine environment. A version of CAM-chem, updated to include aldehyde emissions from the ocean to close the gap between models and measurements, is used in these analyses. Comparisons between measured and modeled halogen containing species, both organic and inorganic, is presented along with a summary of the implications of our findings on the overall budgets of tropospheric halogens and ozone.</p>

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