scholarly journals Observation of atmospheric peroxides during Wangdu Campaign 2014 at a rural site in the North China Plain

2016 ◽  
Vol 16 (17) ◽  
pp. 10985-11000 ◽  
Author(s):  
Yin Wang ◽  
Zhongming Chen ◽  
Qinqin Wu ◽  
Hao Liang ◽  
Liubin Huang ◽  
...  
Keyword(s):  
Biomass Burning ◽  
North China Plain ◽  
North China ◽  
Chemical Mechanism ◽  
Rural Site ◽  
Direct Production ◽  
The North ◽  
The North China Plain ◽  
The Impact ◽  
Haze Days

Abstract. Measurements of atmospheric peroxides were made during Wangdu Campaign 2014 at Wangdu, a rural site in the North China Plain (NCP) in summer 2014. The predominant peroxides were detected to be hydrogen peroxide (H2O2), methyl hydroperoxide (MHP) and peroxyacetic acid (PAA). The observed H2O2 reached up to 11.3 ppbv, which was the highest value compared with previous observations in China at summer time. A box model simulation based on the Master Chemical Mechanism and constrained by the simultaneous observations of physical parameters and chemical species was performed to explore the chemical budget of atmospheric peroxides. Photochemical oxidation of alkenes was found to be the major secondary formation pathway of atmospheric peroxides, while contributions from alkanes and aromatics were of minor importance. The comparison of modeled and measured peroxide concentrations revealed an underestimation during biomass burning events and an overestimation on haze days, which were ascribed to the direct production of peroxides from biomass burning and the heterogeneous uptake of peroxides by aerosols, respectively. The strengths of the primary emissions from biomass burning were on the same order of the known secondary production rates of atmospheric peroxides during the biomass burning events. The heterogeneous process on aerosol particles was suggested to be the predominant sink for atmospheric peroxides. The atmospheric lifetime of peroxides on haze days in summer in the NCP was about 2–3 h, which is in good agreement with the laboratory studies. Further comprehensive investigations are necessary to better understand the impact of biomass burning and heterogeneous uptake on the concentration of peroxides in the atmosphere.

scholarly journals Observation of atmospheric peroxides during Wangdu Campaign 2014 at a rural site in the North China Plain

2016 ◽  
Author(s):  
Yin Wang ◽  
Zhongming Chen ◽  
Qinqin Wu ◽  
Hao Liang ◽  
Liubin Huang ◽  
...  
Keyword(s):  
Biomass Burning ◽  
North China Plain ◽  
North China ◽  
Chemical Mechanism ◽  
Rural Site ◽  
Direct Production ◽  
The North ◽  
The North China Plain ◽  
The Impact ◽  
Haze Days

Abstract. Measurements of atmospheric peroxides were made during Wangdu Campaign 2014 at Wangdu, a rural site in the North China Plain (NCP) in summer 2014. The predominant peroxides were detected to be hydrogen peroxide (H2O2), methyl hydroperoxide (MHP) and peroxyacetic acid (PAA). The observed H2O2 reached up to 11.3 ppbv, which was the highest value compared with previous observations in China at summer time. A box model simulation based on the Master Chemical Mechanism and constrained by the simultaneous observations of physical parameters and chemical species was performed to explore the chemical budget of atmospheric peroxides. Photochemical oxidation of alkenes was found to be the major secondary formation pathway of atmospheric peroxides, while contributions from alkanes and aromatics were of minor importance. The comparison of modelled and measured peroxide concentrations revealed an underestimation during biomass burning events and an overestimation on haze days, which were ascribed to the direct production of peroxides from biomass burning and the heterogeneous uptake of peroxides by aerosols, respectively. The strengths of the primary emissions from biomass burning were on the same order of the known secondary production rates of atmospheric peroxides during the biomass burning events. The heterogeneous process on aerosol particles was suggested to be the predominant sink for atmospheric peroxides. The atmospheric lifetime of peroxides on haze days in summer in the NCP was about 2–3 hours, which is in good agreement with the laboratory studies. Further comprehensive investigations are necessary to better understand the impact of biomass burning and heterogeneous uptake on the concentration of peroxides in the atmosphere.

scholarly journals Radical chemistry at a rural site (Wangdu) in the North China Plain: Observation and model calculations of OH, HO<sub>2</sub> and RO<sub>2</sub> radicals

2016 ◽  
Author(s):  
Zhaofeng Tan ◽  
Hendrik Fuchs ◽  
Keding Lu ◽  
Birger Bohn ◽  
Sebastian Broch ◽  
...  
Keyword(s):  
North China Plain ◽  
North China ◽  
Chemical Mechanism ◽  
Ozone Production ◽  
Rural Site ◽  
Daily Maximum ◽  
Model Calculations ◽  
Mixing Ratios ◽  
The North ◽  
The North China Plain

Abstract. A comprehensive field campaign was carried out in summer 2014 in Wangdu located in the North China Plain. A month of continuous OH, HO2 and RO2 measurements were achieved. Observations of radicals by laser induced fluorescence (LIF) technique gave daily maximum concentrations between (5–15) × 106 cm−3, (3–14) × 108 cm−3 and (3–15) × 108 cm−3 for OH, HO2 and RO2, respectively. Measured OH reactivities (inverse OH lifetimes) were 10 to 20 s−1 during daytime. A chemical box model constrained by trace-gas observations and based on a state-of-the-art chemical mechanism is used to interpret the observed radical concentrations. In general, the model can reasonably well reproduce measured radical concentrations during daytime. Like in previous field campaigns in China, modelled and measured OH concentrations agree for NO mixing ratios higher than 1 ppbv, but systematic discrepancies are observed in the afternoon for NO mixing ratios of less than 300 pptv (the model-measurement ratio is between 1.4 to 2 in this case). If additional OH recycling equivalent to 100 pptv NO is assumed, the model is also capable of reproducing the observed OH concentrations for conditions of high VOC and low NOx concentrations with good agreement in HO2 and RO2. Observed RO2 concentrations are underestimated in the morning hours by a factor of 3 to 5. This indicates that an additional chemical source of RO2 is missing in the model. The OH reactivity is also underpredicted in the early morning. Increasing VOC concentrations to match measured OH reactivity helps to reduce the discrepancy between modelled and measured RO2. The underprediction of RO2 coincides with high NO concentrations and therefore leads to a significant underestimation of the local ozone production rates determined from the peroxy radical (HO2 and RO2) reactions with NO. The underestimation corresponds to a daily integral ozone production of about 20 ppbv per day.

scholarly journals Chemical characteristics of PM<sub>2.5</sub>: Impact of biomass burning at an agricultural site of the North China Plain during a season of transition

2020 ◽  
Author(s):  
Linlin Liang ◽  
Guenter Engling ◽  
Chang Liu ◽  
Wanyun Xu ◽  
Xuyan Liu ◽  
...  
Keyword(s):  
Biomass Burning ◽  
North China Plain ◽  
North China ◽  
Inorganic Ions ◽  
Ambient Air ◽  
Rural Site ◽  
Chemical Components ◽  
Chemical Characteristics ◽  
The North ◽  
The North China Plain

Abstract. Biomass burning (BB) activities are ubiquitous in China, especially in North China, where there is an enormous rural population and winter heating custom. In order to better understand their impacts on aerosol chemical characteristics in rural and agricultural areas of the North China Plain, BB tracers (i.e., levoglucosan (LG), mannosan (MN) and potassium (K+)), as well as other chemical components were quantified at a rural site (Gucheng, GC) from 15 October to 30 November, during a transition heating season, when the field burning of agricultural residues was becoming intense. The measured daily average PM2.5 concentrations of LG, MN and K+ during this study were 0.79 ± 0.75 μg m−3, 0.03 ± 0.03 μg m−3 and 1.52 ± 0.62 μg m−3. Due to the planetary boundary layer development, carbonaceous components and BB tracers showed higher levels at nighttime than daytime, while OM and secondary inorganic ions were enhanced during daytime, likely due to enhanced photochemical activity. An episode with high levels of BB tracers was encountered at the end of October, 2016, with high LG at 4.37 μg m−3. Based on the comparison of chemical components during different BB periods, it appeared that biomass combustion can obviously elevate carbonaceous components levels, whereas there seems to be essentially no effect on secondary inorganic ions in the ambient air. Moreover, the LG / MN ratios in different BB periods were consistent, while the LG / K+ ratio during intensive BB periods was significantly elevated at times, with K+ not increasing as much as LG during intensive BB episodes. This indicated that there were other sources of K+ in the study region, such as fireworks, fertilizer use, or soil resuspension, which don't have variable contributions of K+ during the intensive BB periods; however, local soft wood and vegetation combustion can't be excluded, which have efficient formation of levoglucosan during flaming fires.

scholarly journals Secondary aerosol formation alters CCN activity in the North China Plain

2021 ◽  
Vol 21 (9) ◽  
pp. 7409-7427
Author(s):  
Jiangchuan Tao ◽  
Ye Kuang ◽  
Nan Ma ◽  
Juan Hong ◽  
Yele Sun ◽  
...  
Keyword(s):  
North China Plain ◽  
North China ◽  
Size Range ◽  
Particle Mass ◽  
Rural Site ◽  
Formation Mechanisms ◽  
The North ◽  
The North China Plain ◽  
The Impact ◽  
Ccn Activity

Abstract. Secondary aerosols (SAs, including secondary organic and inorganic aerosols, SOAs and SIAs) are predominant components of aerosol particles in the North China Plain (NCP), and their formation has significant impacts on the evolution of particle size distribution (PNSD) and hygroscopicity. Previous studies have shown that distinct SA formation mechanisms can dominate under different relative humidity (RH). This would lead to different influences of SA formation on the aerosol hygroscopicity and PNSD under different RH conditions. Based on the measurements of size-resolved particle activation ratio (SPAR), hygroscopicity distribution (GF-PDF), PM2.5 chemical composition, PNSD, meteorology and gaseous pollutants in a recent field campaign, McFAN (Multiphase chemistry experiment in Fogs and Aerosols in the North China Plain), conducted during the autumn–winter transition period in 2018 at a polluted rural site in the NCP, the influences of SA formation on cloud condensation nuclei (CCN) activity and CCN number concentration (NCCN) calculation under different RH conditions were studied. Results suggest that during daytime, SA formation could lead to a significant increase in NCCN and a strong diurnal variation in SPAR at supersaturations lower than 0.07 %. During periods with daytime minimum RH exceeding 50 % (high RH conditions), SA formation significantly contributed to the particle mass and size changes in a broad size range of 150 to 1000 nm, leading to NCCN (0.05 %) increases within the size range of 200 to 500 nm and mass concentration growth mainly for particles larger than 300 nm. During periods with daytime minimum RH below 30 % (low RH conditions), SA formation mainly contributed to the particle mass and size and NCCN changes for particles smaller than 300 nm. As a result, under the same amount of mass increase induced by SA formation, the increase of NCCN (0.05 %) was stronger under low RH conditions and weaker under high RH conditions. Moreover, the diurnal variations of the SPAR parameter (inferred from CCN measurements) due to SA formation varied with RH conditions, which was one of the largest uncertainties within NCCN predictions. After considering the SPAR parameter (estimated through the number fraction of hygroscopic particles or mass fraction of SA), the relative deviation of NCCN (0.05 %) predictions was reduced to within 30 %. This study highlights the impact of SA formation on CCN activity and NCCN calculation and provides guidance for future improvements of CCN predictions in chemical-transport models and climate models.

scholarly journals Role of ambient ammonia in particulate ammonium formation at a rural site in the North China Plain

2018 ◽  
Vol 18 (1) ◽  
pp. 167-184 ◽  
Author(s):  
Zhaoyang Meng ◽  
Xiaobin Xu ◽  
Weili Lin ◽  
Baozhu Ge ◽  
Yulin Xie ◽  
...  
Keyword(s):  
North China Plain ◽  
North China ◽  
Water Soluble ◽  
Precipitation Event ◽  
Rural Site ◽  
The North ◽  
The North China Plain ◽  
Hourly Data ◽  
The Impact ◽  
Particulate Ammonium

Abstract. The real-time measurements of NH3 and trace gases were conducted, in conjunction with semi-continuous measurements of water-soluble ions in PM2.5 at a rural site in the North China Plain (NCP) from May to September 2013 in order to better understand chemical characteristics of ammonia and the impact of secondary ammonium aerosols on formation in the NCP. Extremely high NH3 and NH4+ concentrations were observed after a precipitation event within 7–10 days following urea application. Elevated NH3 levels coincided with elevated NH4+, indicating that NH3 likely influenced particulate ammonium mass. For the sampling period, the average conversion ∕ oxidation ratios for NH4+ (NHR), SO42- (SOR), and NO3- (NOR) were estimated to be 0.30, 0.64, and 0.24, respectively. The increased NH3 concentrations, mainly from agricultural activities and regional transport, coincided with the prevailing meteorological conditions. The high NH3 level with NHR of about 0.30 indicates that the emission of NH3 in the NCP is much higher than needed for aerosol acid neutralisation, and NH3 plays an important role in the formation of secondary aerosols as a key neutraliser. The hourly data obtained were used to investigate gas–aerosol partitioning characteristics using the thermodynamic equilibrium model ISORROPIA-II. Modelled SO42-, NO3-, and NH3 values agree well with the measurements, while the modelled NH4+ values largely underestimate the measurements. Our observation and modelling results indicate that strong acids in aerosol are completely neutralised. Additional NH4+ exists in aerosol, probably a result of the presence of a substantial amount of oxalic and other diacids.

scholarly journals Impact of crop field burning and mountains on heavy haze in the North China Plain: A case study

2016 ◽  
Author(s):  
X. Long ◽  
X. X. Tie ◽  
J. J. Cao ◽  
R. J. Huang ◽  
T. Feng ◽  
...  
Keyword(s):  
Air Pollution ◽  
North China Plain ◽  
North China ◽  
Wind Condition ◽  
Beijing City ◽  
The North ◽  
The North China Plain ◽  
Crop Field ◽  
The Impact ◽  
Field Burning

Abstract. Crop field burning (CFB) has important effects on air pollution in China, but it is seldom quantified and reported in a regional scale, which is of great importance for the control strategies of CFB in China, especially in the North China Plain (NCP). With the provincial statistical data and open crop fires captured by satellite (MODIS), we extracted a detailed emission inventory of CFB during a heavy haze event from 6th to 12th October 2014. A regional dynamical and chemical model (WRF-Chem) was applied to investigate the impact of CFB on air pollution in NCP. The model simulations were compared with the in situ measurements of PM2.5 (particular matter with radius less than 2.5 μm) concentrations. The model evaluation shows that the correlation coefficients (R) between measured and calculated values exceeds 0.80 and absolute normalized mean bias (NMB) is no more than 14 %. In addition, the simulated meteorological parameters such as winds and planetary boundary layer height (PBLH) are also in good agreement with observations. The model was intensive used to study (1) the impacts of CFB and (2) the effect of mountains on regional air quality. The results show that the CFB occurred in southern NCP (SNCP) had significant effect on PM2.5 concentrations locally, causing a maximum of 35 % PM2.5 increase in SNCP. Because of south wind condition, the CFB pollution plume is subjective a long transport to northern NCP (NNCP-with several mega cities, including Beijing of the capital city in China), where there are no significant CFB occurrences, causing a maximum of 32 % PM2.5 increase in NNCP. As a result, the heavy haze in Beijing is enhanced by the CFB occurred in SNCP. Further more, there are two major mountains located in the western and northern NCP. Under the south wind condition, these mountains play important roles in enhancing the PM2.5 pollution in NNCP through the blocking and guiding effects. This study suggests that the PM2.5 emissions in SNCP region should be significantly limited in order to reduce the occurrences of heavy haze events in NNCP region, including the Beijing City.

scholarly journals Aerosol vertical mass flux measurements during heavy aerosol pollution episodes at a rural site and an urban site in the Beijing area of the North China Plain

2019 ◽  
Vol 19 (20) ◽  
pp. 12857-12874 ◽  
Author(s):  
Renmin Yuan ◽  
Xiaoye Zhang ◽  
Hao Liu ◽  
Yu Gui ◽  
Bohao Shao ◽  
...  
Keyword(s):  
Mass Flux ◽  
North China Plain ◽  
North China ◽  
Rural Site ◽  
Urban Site ◽  
The North ◽  
The North China Plain ◽  
Aerosol Pollution ◽  
The Mean ◽  
Pollution Episodes

Abstract. Due to excessive anthropogenic emissions, heavy aerosol pollution episodes (HPEs) often occur during winter in the Beijing–Tianjin–Hebei (BTH) area of the North China Plain. Extensive observational studies have been carried out to understand the causes of HPEs; however, few measurements of vertical aerosol fluxes exist, despite them being the key to understanding vertical aerosol mixing, specifically during weak turbulence stages in HPEs. In the winter of 2016 and the spring of 2017 aerosol vertical mass fluxes were measured by combining large aperture scintillometer (LAS) observations, surface PM2.5 and PM10 mass concentrations, and meteorological observations, including temperature, relative humidity (RH), and visibility, at a rural site in Gucheng (GC), Hebei Province, and an urban site at the Chinese Academy of Meteorological Sciences (CAMS) in Beijing located 100 km to the northeast. These are based on the light propagation theory and surface-layer similarity theory. The near-ground aerosol mass flux was generally lower in winter than in spring and weaker in rural GC than in urban Beijing. This finding provides direct observational evidence for a weakened turbulence intensity and low vertical aerosol fluxes in winter and polluted areas such as GC. The HPEs included a transport stage (TS), an accumulative stage (AS), and a removal stage (RS). During the HPEs from 25 to 31 January 2017, in Beijing, the mean mass flux decreased by 51 % from 0.0049 mg m−2 s−1 in RSs to 0.0024 mg m−2 s−1 in the TSs. During the ASs, the mean mass flux decreased further to 0.00087 mg m−2 s−1, accounting for approximately one-third of the flux in the TSs. A similar reduction from the TSs to ASs was observed in the HPE from 16 to 22 December 2016 in GC. It can be seen that from the TS to the AS, the aerosol vertical turbulent flux decreased, but the aerosol particle concentration within the surface layer increased, and it is inferred that in addition to the contribution of regional transport from upwind areas during the TS, suppression of vertical turbulence mixing confining aerosols to a shallow boundary layer increased accumulation.

scholarly journals Influence of biomass burning on mixing state of sub-micron aerosol particles in the North China Plain

2017 ◽  
Vol 164 ◽  
pp. 259-269 ◽  
Author(s):  
Simonas Kecorius ◽  
Nan Ma ◽  
Monique Teich ◽  
Dominik van Pinxteren ◽  
Shenglan Zhang ◽  
...  
Keyword(s):  
Biomass Burning ◽  
North China Plain ◽  
North China ◽  
Aerosol Particles ◽  
Mixing State ◽  
The North ◽  
The North China Plain

Aerosol chemical compositions in the North China Plain and the impact on the visibility in Beijing and Tianjin

2018 ◽  
Vol 201 ◽  
pp. 235-246 ◽  
Author(s):  
Jianan Zou ◽  
Zirui Liu ◽  
Bo Hu ◽  
Xiaojuan Huang ◽  
Tianxue Wen ◽  
...  
Keyword(s):  
North China Plain ◽  
North China ◽  
Chemical Compositions ◽  
The North ◽  
The North China Plain ◽  
The Impact
Sign in / Sign up

Export Citation Format

Share Document