scholarly journals NH<sub>3</sub>-promoted hydrolysis of NO<sub>2</sub> induces explosive growth in HONO

2019 ◽  
Vol 19 (16) ◽  
pp. 10557-10570 ◽  
Author(s):  
Wanyun Xu ◽  
Ye Kuang ◽  
Chunsheng Zhao ◽  
Jiangchuan Tao ◽  
Gang Zhao ◽  
...  
Keyword(s):  
Ph Value ◽  
Pollution Abatement ◽  
Primary Source ◽  
Field Measurements ◽  
Control Measures ◽  
Oh Radicals ◽  
Aerosol Formation ◽  
Atmospheric Photochemistry ◽  
Secondary Aerosol ◽  
Hydrolysis Of

Abstract. The study of atmospheric nitrous acid (HONO), which is the primary source of OH radicals, is crucial with respect to understanding atmospheric photochemistry and heterogeneous chemical processes. Heterogeneous NO2 chemistry under haze conditions has been identified as one of the missing sources of HONO on the North China Plain, and also produces sulfate and nitrate. However, controversy exists regarding the various proposed HONO production mechanisms, mainly regarding whether SO2 directly takes part in the HONO production process and what roles NH3 and the pH value play. In this paper, never before seen explosive HONO production was reported and evidence was found – for the first time in field measurements during fog (usually with 4< pH <6) and haze episodes under high relative humidity (pH ≈4) – that NH3 was the key factor that promoted the hydrolysis of NO2, leading to the explosive growth of HONO and nitrate under both high and relatively lower pH conditions. The results also suggest that SO2 plays a minor or insignificant role in HONO formation during fog and haze events, but was indirectly oxidized upon the photolysis of HONO via subsequent radical mechanisms. Aerosol hygroscopicity significantly increased with rapid inorganic secondary aerosol formation, further promoting HONO production as a positive feedback. For future photochemical and aerosol pollution abatement, it is crucial to introduce effective NH3 emission control measures, as NH3-promoted NO2 hydrolysis is a large daytime HONO source, releasing large amounts of OH radicals upon photolysis, which will contribute largely to both atmospheric photochemistry and secondary aerosol formation.

scholarly journals NH<sub>3</sub>-promoted hydrolysis of NO<sub>2</sub> induces explosive growth in HONO

2018 ◽  
Author(s):  
Wanyun Xu ◽  
Ye Kuang ◽  
Chunsheng Zhao ◽  
Jiangchuan Tao ◽  
Gang Zhao ◽  
...  
Keyword(s):  
North China Plain ◽  
North China ◽  
Ph Value ◽  
Primary Source ◽  
Field Measurements ◽  
Oh Radicals ◽  
The North ◽  
The North China Plain ◽  
First Time ◽  
Hydrolysis Of

Abstract. The study of atmospheric nitrous acid (HONO), which is the primary source of OH radicals, is crucial to atmospheric photochemistry and heterogeneous chemical processes. The heterogeneous NO2 chemistry under haze conditions was pointed out to be one of the missing sources of HONO on the North China Plain, producing sulfate and nitrate in the process. However, controversy exists between various proposed mechanisms, mainly debating on whether SO2 directly takes part in the HONO production process and what roles NH3 and the pH value play in it. In this paper, never before seen explosive HONO production (maximum rate: 16 ppb/hour) was reported and evidence was found for the first time in field measurements during fog episodes (usually with pH > 5) and haze episodes under high relative humidity (usually with pH 

scholarly journals The promotion effect of nitrous acid on aerosol formation in wintertime Beijing: possible contribution of traffic-related emission

2020 ◽  
Author(s):  
Yongchun Liu ◽  
Yusheng Zhang ◽  
Chaofan Lian ◽  
Chao Yan ◽  
Zeming Feng ◽  
...  
Keyword(s):  
Nitrous Acid ◽  
Field Measurements ◽  
Oxidative Capacity ◽  
Early Morning ◽  
Ambient Atmosphere ◽  
Aerosol Formation ◽  
Secondary Aerosol ◽  
Aerosol Mass ◽  
Direct Emission ◽  
Haze Formation

Abstract. Secondary aerosol is a major component of PM2.5, yet its formation mechanism in the ambient atmosphere is still an open question. Based on field measurements in downtown Beijing, we show that the photolysis of nitrous acid (HONO) could promote the formation of organic and nitrate aerosol in wintertime Beijing as evidenced by the growth of the mass concentration of organic and nitrate aerosols linearly increasing as a function of consumed HONO from early morning to noon. The increased nitrate also lead to the formation of particulate matter ammonium by enhancing the neutralization of nitric acid by ammonia. We further illustrate that over 50 % of the ambient HONO during pollution events in wintertime Beijing might be related to traffic-related emission including direct emission and formation via the reaction between OH and vehicle-emitted NO. Overall, our results highlight that the traffic-related HONO plays an important role in the oxidative capacity and in turn, contribute to the haze formation in winter Beijing. Mitigation of HONO and NOx emission from the vehicles might be an effective way to reduce secondary aerosol mass formation and severe haze events in wintertime Beijing.

Atmospheric photochemistry and secondary aerosol formation of urban air in Lyon, France

2021 ◽  
Vol 99 ◽  
pp. 311-323
Author(s):  
Salah Eddine Sbai ◽  
Chunlin Li ◽  
Antoinette Boreave ◽  
Nicolas Charbonnel ◽  
Sebastien Perrier ◽  
...  
Keyword(s):  
Urban Air ◽  
Aerosol Formation ◽  
Atmospheric Photochemistry ◽  
Secondary Aerosol

scholarly journals Secondary organic aerosol formation from biomass burning emissions

2019 ◽  
Author(s):  
Christopher Y. Lim ◽  
David H. Hagan ◽  
Matthew M. Coggon ◽  
Abigail R. Koss ◽  
Kanako Sekimoto ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Secondary Organic Aerosol ◽  
Total Concentration ◽  
Organic Aerosol ◽  
Oh Radicals ◽  
Aerosol Formation ◽  
Atmospheric Aging ◽  
Aerosol Mass ◽  
Photochemical Aging ◽  
Organic Gases

Abstract. Biomass burning is an important source of aerosol and trace gases to the atmosphere, but how these emissions change chemically during their lifetimes is not fully understood. As part of the Fire Influence on Regional and Global Environments Experiment (FIREX 2016), we investigated the effect of photochemical aging on biomass burning organic aerosol (BBOA), with a focus on fuels from the western United States. Emissions were sampled into a small (150 L) environmental chamber and photochemically aged via the addition of ozone and irradiation by 254 nm light. While some fraction of species undergoes photolysis, the vast majority of aging occurs via reaction with OH radicals, with total OH exposures corresponding to the equivalent of up to 10 days of atmospheric oxidation. For all fuels burned, large and rapid changes are seen in the ensemble chemical composition of BBOA, as measured by an aerosol mass spectrometer (AMS). Secondary organic aerosol (SOA) formation is seen for all aging experiments and continues to grow with increasing OH exposure, but the magnitude of the SOA formation is highly variable between experiments. This variability can be explained well by a combination of experiment-to-experiment differences in OH exposure and the total concentration of non-methane organic gases (NMOGs) in the chamber before oxidation, measured by PTR-ToF-MS (r2 values from 0.64 to 0.83). From this relationship, we calculate the fraction of carbon from biomass burning NMOGs that is converted to SOA as a function of equivalent atmospheric aging time, with carbon yields ranging from 24 ± 4 % after 6 hours to 56 ± 9 % after 4 days.

scholarly journals Impacts of primary emissions and secondary aerosol formation on air pollution in an urban area of China during the COVID-19 lockdown

2021 ◽  
Vol 150 ◽  
pp. 106426
Author(s):  
Jie Tian ◽  
Qiyuan Wang ◽  
Yong Zhang ◽  
Mengyuan Yan ◽  
Huikun Liu ◽  
...  
Keyword(s):  
Air Pollution ◽  
Urban Area ◽  
Aerosol Formation ◽  
Secondary Aerosol ◽  
Primary Emissions

The Formation of Plasma Acid at Atmospheric Pressure and its Application in Hydrolysis of Microcrystalline Cellulose

2013 ◽  
Vol 750-752 ◽  
pp. 1626-1629
Author(s):  
Bo Yuan ◽  
Ying Wang ◽  
Ying Chao Ji ◽  
Qiu Hong Wang
Keyword(s):  
Microcrystalline Cellulose ◽  
Atmospheric Pressure ◽  
High Performance ◽  
Barrier Discharge ◽  
Ph Value ◽  
Reducing Sugar ◽  
Dielectric Barrier ◽  
Integrated Optical ◽  
Hydrolysis Of ◽  
Single Factor Experiment

In this paper, plasma acid was obtained by treating distilled water with dielectric barrier discharge at atmospheric pressure in order to hydrolyze cellulose. The acidity of plasma acid was studied through a single factor experiment. A plasma acid with pH value of 1.42 was obtained and used to hydrolyze microcrystalline cellulose at 80°C for 60min. Under this condition, the integrated optical density (IOD) of the hydrolysis sample was 0.589. Based on standard glucose curve, the total reducing sugar (TRS) was calculated to be 53.75mg and the TRS yield was 53.75%. The filtrate was evaporated to get the solid hydrolysis sample to be analyzed by High-performance liquid chromatography (HPLC). The results showed that the sample mainly consisted of glucose, which proved that microcrystalline cellulose could be hydrolyzed by plasma acid. Therefore, it could be concluded that it was an environmentally friendly and economical method to hydrolyze the microcrystalline cellulose by plasma acid.

Laboratory and field measurements of HONO emissions from agricultural soils in Guangdong of China 

2021 ◽  
Author(s):  
Baobin Han ◽  
Peng Cheng ◽  
Yihang Yu ◽  
Wenda Yang ◽  
Zhilin Tian ◽  
...  
Keyword(s):  
Emission Rate ◽  
Agricultural Soils ◽  
Pore Space ◽  
Primary Source ◽  
Field Measurements ◽  
Laboratory Studies ◽  
Release Rates ◽  
Laboratory Results ◽  
Flux Measurements ◽  
Soil Flux

&lt;p&gt;Laboratory studies indicated that soil could produce considerable nitrous acid (HONO) emissions, which is the main primary source of hydroxyl radical (OH) in the troposphere. However, very few field observations of HONO emission from soil were reported. In order to relate laboratory results and field measurements, we measured HONO emissions from 7 representative agricultural soils (rice, vegetables, orchards, peanuts, potatoes, sugarcane and maize) in Guangdong under controlled laboratory conditions, and took flux measurements on 2 of them (rice and vegetables) by dynamic chambers in the field. Generally, release rates of HONO from the seven soils increased with temperature and varied with soil moisture, and the optimum release rates can be reached under specific values of water-filled pore space (WFPS), which is considered to be beneficial to nitrification. The seven soils' optimum release rates ranged from 1.24 to 43.19 ng kg&lt;sup&gt;-1&lt;/sup&gt; s&lt;sup&gt;-1&lt;/sup&gt;, and the Q&lt;sub&gt;10&lt;/sub&gt; (It is defined as the multiple of the increase of soil gas emission rate when the temperature increases by 10&amp;#8451;) ranged from 1.03 to 2.25. Formulas were deduced from the lab results to express HONO emissions for every soil. Flux measurements on two soils varied around -1 to 4 ng N m&lt;sup&gt;-2&lt;/sup&gt; s&lt;sup&gt;-1&lt;/sup&gt;, and both showed similar diurnal variations with peaks around noontime and very low even negative values during nighttime. There were good correlations between HONO fluxes and soil temperature (R&lt;sup&gt;2&lt;/sup&gt;=0.5). Furthermore, irrigation enhanced the HONO emission substantially. However, a large discrepancy existed between soil HONO emissions measured in lab and low HONO fluxes in field. More investigations are needed to explain the paradox.&lt;/p&gt;

scholarly journals Modeling organic aerosols in a megacity: comparison of simple and complex representations of the volatility basis set approach

2010 ◽  
Vol 10 (12) ◽  
pp. 30205-30277 ◽  
Author(s):  
M. Shrivastava ◽  
J. Fast ◽  
R. Easter ◽  
W. I. Gustafson ◽  
R. A. Zaveri ◽  
...  
Keyword(s):  
Gas Phase ◽  
Secondary Organic Aerosol ◽  
Computational Cost ◽  
Organic Aerosols ◽  
Field Measurements ◽  
Organic Aerosol ◽  
Basis Set ◽  
Aerosol Formation ◽  
Secondary Organic Aerosol Formation ◽  
The City

Abstract. The Weather Research and Forecasting model coupled with chemistry (WRF-Chem) is modified to include a volatility basis set (VBS) treatment of secondary organic aerosol formation. The VBS approach, coupled with SAPRC-99 gas-phase chemistry mechanism, is used to model gas-particle partitioning and multiple generations of gas-phase oxidation of organic vapors. In addition to the detailed 9-species VBS, a simplified mechanism using 2 volatility species (2-species VBS) is developed and tested for similarity to the 9-species VBS in terms of both mass and oxygen-to-carbon ratios of organic aerosols in the atmosphere. WRF-Chem results are evaluated against field measurements of organic aerosols collected during the MILAGRO 2006 campaign in the vicinity of Mexico City. The simplified 2-species mechanism reduces the computational cost by a factor of 2 as compared to 9-species VBS. Both ground site and aircraft measurements suggest that the 9-species and 2-species VBS predictions of total organic aerosol mass as well as individual organic aerosol components including primary, secondary, and biomass burning are comparable in magnitude. In addition, oxygen-to-carbon ratio predictions from both approaches agree within 25%, providing evidence that the 2-species VBS is well suited to represent the complex evolution of organic aerosols. Model sensitivity to amount of anthropogenic semi-volatile and intermediate volatility (S/IVOC) precursor emissions is also examined by doubling the default emissions. Both the emission cases significantly under-predict primary organic aerosols in the city center and along aircraft flight transects. Secondary organic aerosols are predicted reasonably well along flight tracks surrounding the city, but are consistently over-predicted downwind of the city. Also, oxygen-to-carbon ratio predictions are significantly improved compared to prior studies by adding 15% oxygen mass per generation of oxidation; however, all modeling cases still under-predict these ratios downwind as compared to measurements, suggesting a need to further improve chemistry parameterizations of secondary organic aerosol formation.

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