Atmospheric hydrogen peroxide and organic hydroperoxides during PRIDE-PRD'06, China: their concentration, formation mechanism and contribution to secondary aerosols

Abstract. Atmospheric hydrogen peroxide (H2O2) and organic hydroperoxides were measured from 18 to 30 July in 2006 during the PRIDE-PRD'06 campaign at Backgarden, a rural site located 48 km north of Guangzhou, a mega-city in southern China. A ground-based instrument was used as a scrubbing coil collector to sample ambient air, followed by on-site analysis by high-performance liquid chromatography (HPLC) coupled with post-column derivatization and fluorescence detection. The H2O2 mixing ratio over the 13 days ranged from below the detection limit to a maximum of 4.6 ppbv, with a mean (and standard deviation) of (1.26±1.24) ppbv during the daytime (08:00–20:00 LT). Methyl hydroperoxide (MHP), with a maximum of 0.8 ppbv and a mean (and standard deviation) of (0.28±0.10) ppbv during the daytime, was the dominant organic hydroperoxide. Other organic peroxides, including bis-hydroxymethyl hydroperoxide (BHMP), peroxyacetic acid (PAA), hydroxymethyl hydroperoxide (HMHP), 1-hydroxy-ethyl hydroperoxide (1-HEHP) and ethyl hydroperoxide (EHP), were detected occasionally. The concentration of H2O2 exhibited a pronounced diurnal variation on sunny days, with a peak mixing ratio in the afternoon (12:00–18:00 LT), but lacked an explicit diurnal cycle on cloudy days. Sometimes a second peak mixing ratio of H2O2 was observed during the evening, suggesting that H2O2 was produced by the ozonolysis of alkenes. The diurnal variation profile of MHP was, in general, consistent with that of H2O2. The estimation indicated that in the morning the H2O2 detected was formed mostly through local photochemical activity, with the rest probably attributable to vertical transport. It is notable that relatively high levels of H2O2 and MHP were found in polluted air. The unexpectedly high level of HO2 radicals detected in this region can account for the production of hydroperoxides, while the high level of NOx suppressed the formation of hydroperoxides significantly. High concentrations of hydroperoxides were detected in samples of rainwater collected in a heavy shower on 25 July when a typhoon passed through, indicating that a considerable mixing ratio of hydroperoxides, particularly MHP, resided above the upper boundary layer, which might be transported on a regional scale and further influence the redistribution of HOx and ROx radicals. It was found that hydroperoxides, in particular H2O2, play an important role in the formation of secondary sulfate in the aerosol phase, where the heterogeneous reaction might contribute substantially. A negative correlation between hydroperoxides and water-soluble organic compounds (WSOC), a considerable fraction of the secondary organic aerosol (SOA), was observed, providing field evidence for the importance of hydroperoxides in the formation of SOA found in previous laboratory studies. We suggest that hydroperoxides act as an important link between sulfate and organic aerosols, which needs further study and should be considered in current atmospheric models.

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Atmospheric hydrogen peroxide and organic hydroperoxides during PRIDE-PRD'06, China: their concentration, formation mechanism and contribution to secondary aerosols

Atmospheric Chemistry and Physics ◽

10.5194/acp-8-6755-2008 ◽

2008 ◽

Vol 8 (22) ◽

pp. 6755-6773 ◽

Cited By ~ 119

Author(s):

W. Hua ◽

Z. M. Chen ◽

C. Y. Jie ◽

Y. Kondo ◽

A. Hofzumahaus ◽

...

Keyword(s):

Hydrogen Peroxide ◽

Standard Deviation ◽

Diurnal Variation ◽

Regional Scale ◽

Ambient Air ◽

Water Soluble ◽

Rural Site ◽

Mixing Ratio ◽

Field Evidence ◽

Organic Hydroperoxides

Abstract. Atmospheric hydrogen peroxide (H2O2) and organic hydroperoxides were measured from 18 to 30 July in 2006 during the PRIDE-PRD'06 campaign at Backgarden, a rural site located 48 km north of Guangzhou, a mega-city in southern China. A ground-based instrument was used as a scrubbing coil collector to sample ambient air, followed by on-site analysis by high-performance liquid chromatography (HPLC) coupled with post-column derivatization and fluorescence detection. The H2O2 mixing ratio over the 13 days ranged from below the detection limit to a maximum of 4.6 ppbv, with a mean (and standard deviation) of (1.26±1.24) ppbv during the daytime (08:00–20:00 LT). Methyl hydroperoxide (MHP), with a maximum of 0.8 ppbv and a mean (and standard deviation) of (0.28±0.10) ppbv during the daytime, was the dominant organic hydroperoxide. Other organic peroxides, including bis-hydroxymethyl hydroperoxide (BHMP), peroxyacetic acid (PAA), hydroxymethyl hydroperoxide (HMHP), 1-hydroxy-ethyl hydroperoxide (1-HEHP) and ethyl hydroperoxide (EHP), were detected occasionally. The concentration of H2O2 exhibited a pronounced diurnal variation on sunny days, with a peak mixing ratio in the afternoon (12:00–18:00 LT), but lacked an explicit diurnal cycle on cloudy days. Sometimes a second peak mixing ratio of H2O2 was observed during the evening, suggesting that H2O2 was produced by the ozonolysis of alkenes. The diurnal variation profile of MHP was, in general, consistent with that of H2O2. The estimation indicated that in the morning the H2O2 detected was formed mostly through local photochemical activity, with the rest probably attributable to vertical transport. It is notable that relatively high levels of H2O2 and MHP were found in polluted air. The unexpectedly high level of HO2 radicals detected in this region can account for the production of hydroperoxides, while the moderate level of NOx suppressed the formation of hydroperoxides. High concentrations of hydroperoxides were detected in samples of rainwater collected in a heavy shower on 25 July when a typhoon passed through, indicating that a considerable mixing ratio of hydroperoxides, particularly MHP, resided above the boundary layer, which might be transported on a regional scale and further influence the redistribution of HOx and ROx radicals. It was found that hydroperoxides, in particular H2O2, play an important role in the formation of secondary sulfate in the aerosol phase, where the heterogeneous reaction might contribute substantially. A negative correlation between hydroperoxides and water-soluble organic compounds (WSOC), a considerable fraction of the secondary organic aerosol (SOA), was observed, possibly providing field evidence for the importance of hydroperoxides in the formation of SOA found in previous laboratory studies. We suggest that hydroperoxides act as an important link between sulfate and organic aerosols, which needs further study and should be considered in current atmospheric models.

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Spatio-Temporal Variation of Atmospheric Gaseous and Particulate Reactive Nitrogen over Northern India

Current World Environment ◽

10.12944/cwe.16.special-issue1.05 ◽

2021 ◽

Vol Special Issue (1) ◽

pp. 53-67

Author(s):

Manisha Mishra ◽

Umesh C Kulshrestha

Keyword(s):

Source Parameters ◽

Ambient Air ◽

Water Soluble ◽

Rural Site ◽

Urban Site ◽

Local Source ◽

Reactive Nitrogen ◽

Gangetic Plain ◽

Reactive N ◽

Spatio Temporal

The present study reports spatio-temporal distribution pattern of major gaseous (NH3 and NO2) and particulate water soluble total nitrogen (pWSTN) in the ambient air to explore the seasonal variation, major interactions and dominating sources. Considering the major hotspot of atmospheric reactive nitrogen (N) emission, three sites in Indo-Gangetic plain (IGP) were selected based on different local source parameters. Results have shown that gas phase reactive N contribute up to 90% of total analyzed reactive N, where NH3 imparted highest at all the three sites. Prayagraj, a fast growing urban site, has shown highest concentrations of NH3 (72.0 μg m−3), followed by Madhupur rural site (57.7 μg m−3) and Delhi, an urban megacity site (35.8 μg m−3). As compared to previous studies conducted at different sites of IGP, NH3 concentrations were reported to be the highest at the former two sites. However, unlike NH3, NO2 levels were recorded lower at Madhupur (3.1 μg m−3) and Prayagraj (9.4 μg m−3) sites as compared to Delhi (13.4 μg m−3). Similarly, pWSTN concentrations were in the order of Madhupur (6.6 μg m−3) < Prayagraj (10.0 μg m−3) < Delhi (10.1 μg m−3). A strong correlation of NO2 with pWSTN at urban sites has shown the crucial role of NO2 in the formation of nitrogenous aerosols. Significant spatial variation can be attributed to varying local emission sources ranging from microbial emission from improper sewage treatment and open waste dumping at Prayagraj, agricultural activities at Madhupur and vehicular exhausts at Delhi site.

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Chlorine oxidation of VOCs at a semi-rural site in Beijing: significant chlorine liberation from ClNO<sub>2</sub> and subsequent gas- and particle-phase Cl–VOC production

Atmospheric Chemistry and Physics ◽

10.5194/acp-18-13013-2018 ◽

2018 ◽

Vol 18 (17) ◽

pp. 13013-13030 ◽

Cited By ~ 17

Author(s):

Michael Le Breton ◽

Åsa M. Hallquist ◽

Ravi Kant Pathak ◽

David Simpson ◽

Yujue Wang ◽

...

Keyword(s):

Chlorine Atom ◽

Ambient Air ◽

Anthropogenic Sources ◽

Rural Site ◽

Anthropogenic Source ◽

High Time Resolution ◽

Mixing Ratio ◽

Mixing Ratios ◽

Relative Contribution ◽

Unique Markers

Abstract. Nitryl chloride (ClNO2) accumulation at night acts as a significant reservoir for active chlorine and impacts the following day's photochemistry when the chlorine atom is liberated at sunrise. Here, we report simultaneous measurements of N2O5 and a suite of inorganic halogens including ClNO2 and reactions of chloride with volatile organic compounds (Cl–VOCs) in the gas and particle phases utilising the Filter Inlet for Gas and AEROsols time-of-flight chemical ionisation mass spectrometer (FIGAERO-ToF-CIMS) during an intensive measurement campaign 40 km northwest of Beijing in May and June 2016. A maximum mixing ratio of 2900 ppt of ClNO2 was observed with a mean campaign nighttime mixing ratio of 487 ppt, appearing to have an anthropogenic source supported by correlation with SO2, CO and benzene, which often persisted at high levels after sunrise until midday. This was attributed to such high mixing ratios persisting after numerous e-folding times of the photolytic lifetime enabling the chlorine atom production to reach 2.3 × 105 molecules cm−3 from ClNO2 alone, peaking at 09:30 LT and up to 8.4 × 105 molecules cm−3 when including the supporting inorganic halogen measurements.Cl–VOCs were observed in the particle and gas phases for the first time at high time resolution and illustrate how the iodide ToF-CIMS can detect unique markers of chlorine atom chemistry in ambient air from both biogenic and anthropogenic sources. Their presence and abundance can be explained via time series of their measured and steady-state calculated precursors, enabling the assessment of competing OH and chlorine atom oxidation via measurements of products from both of these mechanisms and their relative contribution to secondary organic aerosol (SOA) formation.

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Online Measurement of PM2.5 at an Air Monitoring Supersite in Yangtze River Delta: Temporal Variation and Source Identification

Atmosphere ◽

10.3390/atmos11080789 ◽

2020 ◽

Vol 11 (8) ◽

pp. 789 ◽

Cited By ~ 1

Author(s):

Lian Duan ◽

Lei Yan ◽

Guangli Xiu

Keyword(s):

Yangtze River ◽

Chemical Species ◽

Inorganic Ions ◽

Ambient Air ◽

Yangtze River Delta ◽

River Delta ◽

Water Soluble ◽

Dianshan Lake ◽

Haze Pollution ◽

High Level

To comprehensively explore the transport of air pollutants, one-year continuous online observation of PM2.5 was conducted from 1 April 2015 to 31 March 2016 at Dianshan Lake, a suburban junction at the central of Yangtze River Delta. The chemical species of PM2.5 samples mainly focused on Organic carbon (OC), Elemental carbon (EC) and Water-Soluble Inorganic Ions (WSIIs). The annual average of PM2.5 concentration was 59.8 ± 31.7 µg·m−3, 1.7 times higher than the Chinese National Ambient Air Quality Standards (CNAAQS) (35 µg·m−3). SNA (SO42−, NO3− and NH4+) was the most dominated species of PM2.5 total WSIIs, accounting for 51% of PM2.5. PM2.5 and all of its chemical species shared the same seasonal variations with higher concentration in winter and spring, lower in autumn and summer. The higher NO3−/EC and NOR occurred in winter suggested that intensive secondary formation of nitrate contributed to the higher levels of PM2.5. Cluster analysis based on 72-h backward air trajectory showed that the air mass cluster from nearby inland cities, including Zhejiang, Anhui and Jiangxi Provinces contributed mostly to the total trajectories. Furtherly, potential source contribution function (PSCF) analysis revealed that local sources, namely the emissions in the Yangtze River, were the primary sources. During haze pollution, NO3− was the most important fraction of PM2.5 and the heterogeneous formation of nitrate became conspicuous. All the results suggested that the anthropogenic emissions (such as traffic exhaust) was responsible for the relatively high level of PM2.5 at this monitoring station.

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Characteristics and the origins of the carbonaceous aerosol at a rural site of PRD in summer 2006

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-11-21601-2011 ◽

2011 ◽

Vol 11 (7) ◽

pp. 21601-21629

Author(s):

W. W. Hu ◽

M. Hu ◽

Z. Q. Deng ◽

R. Xiao ◽

Y. Kondo ◽

...

Keyword(s):

Organic Carbon ◽

Organic Aerosol ◽

Early Morning ◽

Water Soluble ◽

Carbonaceous Aerosol ◽

Rural Site ◽

Tracer Method ◽

Good Opportunity ◽

Guangzhou City ◽

High Level

Abstract. Both organic carbon (OC) and elemental carbon (EC) were measured at a rural site, Back Garden (BG), 50km northwest of the Guangzhou City, by using a semi-continuous thermal-optical analyzer during PRIDE-PRD 2006 summer intensive campaign. Together with the online EC/OC instrument, multiple instruments were also employed here which provided a good opportunity to check data quality. The regressions between the mass of organic aerosol (OM) and OC, as well as OC and water soluble organic carbon (WSOC) imply reliability of the data measured in this campaign. The average OC concentrations in fine particle for three typical periods during the campaign (local emission influence, typhoon and participation, normal days) were 28.1 μg C m−3, 4.0 μg C m−3 and 5.7 μg C m−3, respectively, and EC were 11.6 μg C m−3, 1.8 μg C m−3, and 3.3 μg C m−3 orderly. Diurnal variations of EC and OC showed that there were two peaks for EC and OC concentrations, i.e. at night and early morning, which were probably caused by the primary emission accumulation when the boundary layer was shallow. Compare to the constant diurnal enhancement ratios of primary EC, the enhancement ratio of OC (OC versus (CO-CObackground)) remained in a relative high level in the afternoon with a similar diurnal variation to oxygenated organic aerosol (OOA), indicating the strong photochemical formation of OC. The traditional EC tracer method was modified to estimate the secondary organic carbon (SOC) formation, which shows that the average SOC concentration in BG site was about 2.0 ± 2.3 μg C m−3.The SOC fraction in OC reached up to 80 % with the average of 47 %. Good correlations between estimated SOC versus measured OOA or WSOC, and estimated POC versus measured hydrocarbon-like organic aerosol (HOA) also proved the reliable results by the modified EC tracer method in this paper.

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The characteristics and origins of carbonaceous aerosol at a rural site of PRD in summer of 2006

Atmospheric Chemistry and Physics ◽

10.5194/acp-12-1811-2012 ◽

2012 ◽

Vol 12 (4) ◽

pp. 1811-1822 ◽

Cited By ~ 48

Author(s):

W. W. Hu ◽

M. Hu ◽

Z. Q. Deng ◽

R. Xiao ◽

Y. Kondo ◽

...

Keyword(s):

Organic Carbon ◽

Chemical Properties ◽

Organic Aerosol ◽

Early Morning ◽

Water Soluble ◽

Carbonaceous Aerosol ◽

Rural Site ◽

Good Opportunity ◽

Guangzhou City ◽

High Level

Abstract. Both organic carbon (OC) and elemental carbon (EC) were measured during PRIDE-PRD 2006 summer campaign by using a semi-continuous thermal-optical carbon analyzer at a rural site, Back Garden (BG), which is located 50 km to the northwest of Guangzhou City. Together with the online EC/OC analyzer, various kinds of instruments related to aerosol chemical properties were employed here, which provided a good opportunity to check data quality. The concentrations of OC correlated well with the mass of organic matter (OM) and water soluble organic carbon (WSOC), implying the reliability of the data measured in this campaign. The average OC concentrations in fine particle for three typical periods during the campaign (local emission influence, typhoon and precipitation and normal days) were 28.1 μgC m−3, 4.0 μgC m−3 and 5.7 μgC m−3, respectively; and EC were 11.6 μgC m−3, 1.8 μgC m−3, and 3.3 μgC m−3, respectively. The diurnal patterns of EC and OC during the campaign were higher at night and in early morning than daytime, which was probably caused by the primary emission and accumulation in the occurrence of low boundary layer. Compared with the constant diurnal enhancement ratios of EC, the enhancement ratio of OC (OC versus (CO-CObackground)) kept in a relative high level in the afternoon, with a similar diurnal profile to oxygenated organic aerosol (OOA), due to the strong photochemical formation of OC. Here, a modified EC tracer method was used to estimate the formation of secondary organic carbon (SOC). These results showed that the average SOC concentration (normal days) at BG site was about 2.0 ± 2.3 μgC m−3, and the SOC fraction in OC could reach up to 80% with the average of 47%. The modified approach in this study proved to be effective and reliable for SOC estimation based on good correlations between estimated SOC versus OOA or WSOC, and estimated POC versus hydrocarbon-like organic aerosol (HOA).

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Neurotoxicity and Neuroprotective Effects of Polyimides (PI) and Polyphenylenevinylene (PPV) against Hydrogen Peroxide (H2O2)

Scientific Research Journal ◽

10.24191/srj.v8i2.5049 ◽

2011 ◽

Vol 8 (2) ◽

pp. 33

Author(s):

Norfaezah Mazalan ◽

Mazatulikhma Mat Zain ◽

Nor Saliyana Jumali ◽

Norhanim Mohalid ◽

Zurina Shaameri ◽

...

Keyword(s):

Hydrogen Peroxide ◽

Drug Delivery Systems ◽

Neuronal Cells ◽

Water Soluble ◽

Brain Delivery ◽

Specific Therapy ◽

Neuroprotective Effects ◽

Water Soluble Polymer ◽

Site Specific ◽

Novel Drugs

Recently, research and development in the field of drug delivery systems (DDS) facilitating site-specific therapy has reached significant progression. DDS based on polymer micelles, coated micro- and nanoparticles, and various prodrug systems including water-soluble polymer have been prepared and extensively studied as novel drugs designed for cancer chemotherapy and brain delivery. Since polymers are going to be used in human, this study has the interest of testing two types of polymer, polyimides (PI) and polyphenylenevinylene (PPV) on neuronal cells. The objective of this study was to determine the possible neurotoxicity and potential neuroprotective effects of PI and PPV towards SH-SY5Y neuronal cells challenged by hydrogen peroxide (H2O2) as an oxidant. Cells were pretreated with either PI or PPV for 1 hour followed by incubation for 24 hour with 100 µM of H2O2. MTS assay was used to assess cell viability. Results show that PI and PPV are not harmful within the concentration up to 10 µM and 100 µM, respectively. However, PI and PPV do not protect neuronal cells against toxicity induced by H2O2 or further up the cell death.

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Jam processing: Effect of pectin replacement by locust bean gum on its characteristics

Mediterranean Journal of Nutrition and Metabolism ◽

10.3233/mnm-200493 ◽

2020 ◽

pp. 1-12

Author(s):

Aida Mekhoukhe ◽

Nacer Mohellebi ◽

Tayeb Mohellebi ◽

Leila Deflaoui-Abdelfettah ◽

Sonia Medouni-Adrar ◽

...

Keyword(s):

Cold Water ◽

Physicochemical Characteristics ◽

Water Soluble ◽

Sensory Profile ◽

Locust Bean Gum ◽

Locust Bean ◽

Preference Map ◽

The Right ◽

High Level ◽

The Impact

OBJECTIVE: the present work proposed to extract Locust Bean Gum (LBG) from Algerian carob fruits, evaluate physicochemical and rheological properties (solubility). It aimed also to develop different formulations of strawberry jams with a mixture of LBG and pectin in order to obtain a product with a high sensory acceptance. METHODS: the physicochemical characteristics of LBG were assessed. The impact of temperature on solubility was also studied. The physical and the sensory profile and acceptance of five Jams were evaluated. RESULTS: composition results revealed that LBG presented a high level of carbohydrate but low concentrations of fat and ash. The LBG was partially cold-water-soluble (∼62% at 25°C) and needed heating to reach a higher solubility value (∼89% at 80 °C). Overall, the sensorial acceptances decreased in jams J3 which was formulated with 100% pectin and commercial one (J5). The external preference map explained that most consumers were located to the right side of the map providing evidence that most samples appreciated were J4 and J2 (rate of 80–100%). CONCLUSION: In this investigation, the LBG was used successfully in the strawberry jam’s formulation.

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Optimization of the Local Split-Window Algorithm for FY-4A Land Surface Temperature Retrieval

Remote Sensing ◽

10.3390/rs11172016 ◽

2019 ◽

Vol 11 (17) ◽

pp. 2016

Author(s):

Lijuan Wang ◽

Ni Guo ◽

Wei Wang ◽

Hongchao Zuo

Keyword(s):

Surface Temperature ◽

Diurnal Variation ◽

Land Surface Temperature ◽

Satellite Data ◽

Land Surface ◽

Regional Scale ◽

Pso Algorithm ◽

Variation Characteristics ◽

Split Window Algorithm ◽

Mean Square Errors

FY-4A is a second generation of geostationary orbiting meteorological satellite, and the successful launch of FY-4A satellite provides a new opportunity to obtain diurnal variation of land surface temperature (LST). In this paper, different underlying surfaces-observed data were applied to evaluate the applicability of the local split-window algorithm for FY-4A, and the local split-window algorithm parameters were optimized by the artificial intelligent particle swarm optimization (PSO) algorithm to improve the accuracy of retrieved LST. Results show that the retrieved LST can efficiently reproduce the diurnal variation characteristics of LST. However, the estimated values deviate hugely from the observed values when the local split-window algorithms are directly used to process the FY-4A satellite data, and the root mean square errors (RMSEs) are approximately 6K. The accuracy of the retrieved LST cannot be effectively improved by merely modifying the emissivity-estimated model or optimizing the algorithm. Based on the measured emissivity, the RMSE of LST retrieved by the optimized local split-window algorithm is reduced to 3.45 K. The local split-window algorithm is a simple and easy retrieval approach that can quickly retrieve LST on a regional scale and promote the application of FY-4A satellite data in related fields.

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