scholarly journals Comments to "Exploration of the atmospheric chemistry of nitrous acid in a coastal city of southeastern China: Results from measurements across four seasons"

2020 ◽  
Author(s):  
Anonymous
Keyword(s):  
Atmospheric Chemistry ◽  
Nitrous Acid ◽  
Southeastern China ◽  
Coastal City ◽  
Four Seasons

scholarly journals Exploration of the atmospheric chemistry of nitrous acid in a coastal city of southeastern China: results from measurements across four seasons

2022 ◽  
Vol 22 (1) ◽  
pp. 371-393
Author(s):  
Baoye Hu ◽  
Jun Duan ◽  
Youwei Hong ◽  
Lingling Xu ◽  
Mengren Li ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Nitrous Acid ◽  
Simulation Models ◽  
Oh Radicals ◽  
Vehicle Exhaust ◽  
Southeastern China ◽  
Coastal City ◽  
Budget Analysis ◽  
Four Seasons ◽  
Conversion Frequency

Abstract. Because nitrous acid (HONO) photolysis is a key source of hydroxyl (OH) radicals, identifying the atmospheric sources of HONO is essential to enhance the understanding of atmospheric chemistry processes and improve the accuracy of simulation models. We performed seasonal field observations of HONO in a coastal city of southeastern China, along with measurements of trace gases, aerosol compositions, photolysis rate constants (J), and meteorological parameters. The results showed that the average observed concentration of HONO was 0.54 ± 0.47 ppb. Vehicle exhaust emissions contributed an average of 1.45 % to HONO, higher than the values found in most other studies, suggesting an influence from diesel vehicle emissions. The mean conversion frequency of NO2 to HONO in the nighttime was the highest in summer due to water droplets evaporating under high-temperature conditions. Based on a budget analysis, the rate of emission from unknown sources (Runknown) was highest around midday, with values of 4.51 ppb h−1 in summer, 3.51 ppb h−1 in spring, 3.28 ppb h−1 in autumn, and 2.08 ppb h−1 in winter. Unknown sources made up the largest proportion of all sources in summer (81.25 %), autumn (73.99 %), spring (70.87 %), and winter (59.28 %). The photolysis of particulate nitrate was probably a source in spring and summer while the conversion from NO2 to HONO on BC enhanced by light was perhaps a source in autumn and winter. The variation of HONO at night can be exactly simulated based on the HONO / NOx ratio, while the J(NO3-_R) × pNO3- should be considered for daytime simulations in summer and autumn, or 1/4× (J(NO3-_R) × pNO3-) in spring and winter. Compared with O3 photolysis, HONO photolysis has long been an important source of OH except for summer afternoons. Observation of HONO across four seasons with various auxiliary parameters improves the comprehension of HONO chemistry in southeastern coastal China.

scholarly journals Exploration of the atmospheric chemistry of nitrous acid in a coastal city of southeastern China: Results from measurements across four seasons

2021 ◽  
Author(s):  
Baoye Hu ◽  
Jun Duan ◽  
Youwei Hong ◽  
Lingling Xu ◽  
Mengren Li ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Nitrous Acid ◽  
Simulation Models ◽  
Oh Radicals ◽  
Vehicle Exhaust ◽  
Southeastern China ◽  
Coastal City ◽  
Budget Analysis ◽  
Four Seasons ◽  
Conversion Frequency

Abstract. Because nitrous acid (HONO) photolysis is a key source of hydroxyl (OH) radicals, identifying the atmospheric sources of HONO is essential to enhance the understanding of atmospheric chemistry processes and improve the accuracy of simulation models. We performed seasonal field observations of HONO in a coastal city of southeastern China, along with measurements of trace gases, aerosol compositions, photolysis rate constants (J), and meteorological parameters. The results showed that the average observed concentration of HONO was 0.54 ± 0.47 ppb. Vehicle exhaust emissions contributed an average of 1.64 % to HONO, higher than the values found in most other studies, suggesting an influence from diesel vehicle emissions. The mean conversion frequency of NO2 to HONO in the nighttime was the highest in summer due to water droplets was evaporated under the condition of high temperatures. Based on a budget analysis, the rate of emission from unknown sources (Runknown) was highest around midday, with values of 4.35 ppb · h−1 in summer, 3.53 ppb · h−1 in spring, 3.13 ppb · h−1 in autumn, and 2.05 in winter. Unknown sources made up the largest proportion of all sources in summer (78.55 %), autumn (71.51 %), spring (69.67 %), and winter (55.63 %). The photolysis of particulate nitrate was probably a source in spring and summer while the conversion from NO2 to HONO on BC enhanced by light was perhaps a source in autumn and winter. The variation of HONO at night can be exactly simulated based on the HONO/NOx ratio, while the J(NO3−_R) × pNO3− should be considered for daytime simulations in summer and autumn, or 1/4 × (J(NO3−_R) × pNO3−) in spring and winter. Compared with O3 photolysis, HONO photolysis has long been an important source of OH except for summer afternoon. Observation on HONO across four seasons with various auxiliary parameters improves the comprehension of HONO chemistry in southeastern coastal China.

scholarly journals Exploration of the atmospheric chemistry of nitrous acid in a coastal city of southeastern China: Results from measurements across four seasons

2020 ◽  
Author(s):  
Baoye Hu ◽  
Jun Duan ◽  
Youwei Hong ◽  
Lingling Xu ◽  
Mengren Li ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Nitrous Acid ◽  
Simulation Models ◽  
Oh Radicals ◽  
Vehicle Exhaust ◽  
Southeastern China ◽  
Coastal City ◽  
Budget Analysis ◽  
Four Seasons ◽  
Logarithmic Relationship

Abstract. Because nitrous acid (HONO) photolysis is a key source of hydroxyl (OH) radicals, identifying the atmospheric sources of HONO is essential to enhance the understanding of atmospheric chemistry processes and improve the accuracy of simulation models. We performed seasonal field observations of HONO in a coastal city of southeastern China, along with measurements of trace gases, aerosol compositions, photolysis rate constants (J), and meteorological parameters. The results showed that the average observed concentration of HONO was 0.54 ± 0.47 ppb. Vehicle exhaust emissions contributed an average of 1.64 % to HONO, higher than the values found in most other studies, suggesting an influence from diesel vehicle emissions. The mean conversion frequency of NO2 to HONO in the nighttime was the highest in summer due to water droplets was evaporated under the condition of high temperatures. Based on a budget analysis, the rate of emission from unknown sources (Runknown) was highest at midday, with values of 14.78 ppb h−1 in summer, 6.49 ppb h−1 in autumn, and 2.18 ppb h−1 in spring. Unknown sources made up the largest proportion of all sources in summer (84.92 %), autumn (80.29 %), and spring (49.98 %), whereas the main source in winter was the homogeneous reaction of NO with OH (56.15 %), due to winter having the highest NO concentration of the four seasons. The value of Runknown had a positive logarithmic relationship with the photolysis of particulate nitrate in spring, summer, and autumn. However, Runknown was limited by particulate acidity under the condition of photolysis of particulate nitrate (J (NO3−_R) × pNO3−) > 1 µg m−3 s−1 in autumn and J(NO3−_R) × pNO3− > 2 µg m−3 s−1 in spring and summer. The variation of HONO at night can be exactly simulated based on the HONO / NOx ratio, while the main sources should be considered for daytime simulations. Compared with O3 photolysis, HONO photolysis has long been an important source of OH, particularly in the morning in spring and winter and around noon in summer and autumn. This study draws a full picture of the sources of HONO across all four seasons and improves the comprehension of HONO chemistry in southeastern coastal China.

scholarly journals Exploring the atmospheric chemistry of nitrous acid (HONO) at a rural site in Southern China

2012 ◽  
Vol 12 (3) ◽  
pp. 1497-1513 ◽  
Author(s):  
X. Li ◽  
T. Brauers ◽  
R. Häseler ◽  
B. Bohn ◽  
H. Fuchs ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Nitrous Acid ◽  
Southern China ◽  
Rural Site ◽  
Pearl River Delta Region ◽  
Additional Source ◽  
Mixing Ratios ◽  
Photolysis Frequency ◽  
The Pearl River

Abstract. We performed measurements of nitrous acid (HONO) during the PRIDE-PRD2006 campaign in the Pearl River Delta region 60 km north of Guangzhou, China, for 4 weeks in June 2006. HONO was measured by a LOPAP in-situ instrument which was setup in one of the campaign supersites along with a variety of instruments measuring hydroxyl radicals, trace gases, aerosols, and meteorological parameters. Maximum diurnal HONO mixing ratios of 1–5 ppb were observed during the nights. We found that the nighttime build-up of HONO can be attributed to the heterogeneous NO2 to HONO conversion on ground surfaces and the OH + NO reaction. In addition to elevated nighttime mixing ratios, measured noontime values of ≈200 ppt indicate the existence of a daytime source higher than the OH + NO→HONO reaction. Using the simultaneously recorded OH, NO, and HONO photolysis frequency, a daytime additional source strength of HONO (PM) was calculated to be 0.77 ppb h−1 on average. This value compares well to previous measurements in other environments. Our analysis of PM provides evidence that the photolysis of HNO3 adsorbed on ground surfaces contributes to the HONO formation.

Characteristics of peroxyacetyl nitrate (PAN) in a coastal city of southeastern China: Photochemical mechanism and pollution process

2020 ◽  
Vol 719 ◽  
pp. 137493
Author(s):  
Baoye Hu ◽  
Taotao Liu ◽  
Youwei Hong ◽  
Lingling Xu ◽  
Mengren Li ◽  
...  
Keyword(s):  
Peroxyacetyl Nitrate ◽  
Southeastern China ◽  
Coastal City

scholarly journals Spatio–Temporal Variations in Impervious Surface Patterns during Urban Expansion in a Coastal City: Xiamen, China

2019 ◽  
Vol 11 (8) ◽  
pp. 2404 ◽  
Author(s):  
Wang Man ◽  
Qin Nie ◽  
Lizhong Hua ◽  
Xuewen Wu ◽  
Hui Li
Keyword(s):  
Urban Sprawl ◽  
Urban Expansion ◽  
Temporal Variations ◽  
Environmental Indicator ◽  
Urban Centers ◽  
Southeastern China ◽  
Coastal City ◽  
Surface Patterns ◽  
Spatio Temporal ◽  
Land Surfaces

Impervious surfaces (IS) coverage is a quantifiable environmental indicator for understanding urban sprawl and its potential impacts on sustainability of urban ecological environments. Numerous studies have previously demonstrated global and regional IS variation, but little attention has been paid to the different internal and external patterns of IS development as urbanization progresses. This study estimates IS coverage in a subtropical coastal area of Xiamen, southeastern China, from Landsat TM/OLI images obtained in 1994, 2000, 2004, 2010, and 2015, and quantifies its spatio–temporal variations using IS change trajectories and radar graphs. During the study period, IS gradually expanded along the shoreline in a pattern resembling the shape of the bay. The land surfaces are classified into four zones: IS1 and IS2, dominated by cultivated land and forest; IS3, complex land use/coverage; and IS4, built-up areas. The progression and transformations of these zones highlight the main trends in IS changes in the study area. The trajectories of the zones form a layered structure in which the urban centers of each district progressively gain IS4, and transformations into IS3 and IS2 extend successively beyond the centers. The orientation of IS expansion in each of the six districts of Xiamen is revealed by radar graphs. The areas containing intermediate and high percentages IS each expanded in generally consistent directions throughout the study period, except in Tong’an district, which showed a change in the direction of expansion of its area of intermediate and high IS.

Development of an incoherent broadband cavity-enhanced absorption spectroscopy (IBBCEAS) instrument for autonomous field measurements of HONO and NO2 in a rural area

2021 ◽  
Author(s):  
Lingshuo Meng ◽  
Gaoxuan Wang ◽  
Cécile Coeur ◽  
Alexandre Tomas ◽  
Tao Wu ◽  
...  
Keyword(s):  
Rural Area ◽  
Absorption Spectroscopy ◽  
Atmospheric Chemistry ◽  
Nitrous Acid ◽  
Trace Gases ◽  
Ambient Air ◽  
Rural Site ◽  
Oh Radicals ◽  
Enhanced Absorption ◽  
Cavity Enhanced Absorption Spectroscopy

<p>Nitrous acid (HONO) is one of the important atmospheric trace gases due to its contribution to the cycles of nitrogen oxides (NOx) and hydrogen oxides (HOx). In particular it acts as a precursor of tropospheric OH radicals, which is responsible for the self-cleansing capacity of the atmosphere [1,2]. We developed an instrument based on incoherent broadband cavity enhanced absorption spectroscopy (IBBCEAS) for automatic measurement of HONO in a rural area in a summer period during a field "Campagne d’OBservation Intensive des Aérosols et précurseurs à Caillouël-Crépigny (COBIACC)" in France. IBBCEAS technique is now extensively used in field applications for the measurements of both trace gases and aerosols [3,4].</p><p>Real-time in situ measurements of HONO and NO<sub>2</sub> have been simultaneously carried out. The IBBCEAS instrument performance has been demonstrated and validated through lab-based tests, and in particular through field intercomparison via side-by-side measurements of temporal concentration profiles of HONO and NO<sub>2</sub> in the rural area. The intercomparison of the concentration measurements between IBBCEAS and an instrument called MARGA (Monitor for AeRosols and Gases in Ambient air) for HONO, and IBBCEAS vs. a reference NOx analyzer for NO<sub>2</sub>. Good agreements have been observed which demonstrated the performance of the developed IBBCEAS instrument for the measurement of atmospheric HONO concentration (<5 ppb) in a rural area.</p><p>The preliminary experimental results will be presented and discussed.</p><p><strong>Acknowledgments</strong> This work was supported by the CPER CLIMIBIO program and the Labex CaPPA project (ANR-10-LABX005). The authors highly appreciate the offers of Mr. Eric Wetzels from Polyfluor Plastics bv for the help in our instrumental conception involving Teflon pipe.</p><p><strong>References</strong></p><p>[1] X. Li, T. Brauers, R. Häseler, R. Bohn, H. Fuchs, A. Hofzumahaus, F. Holland, S. Lou, et al., Exploring the atmospheric chemistry of nitrous acid (HONO) at a rural site in Southern China, Atmos. Chem. Phys. <strong>12</strong> (2012) 1497-1513.</p><p>[2] H. Su, Y. Cheng, M. Shao, D. Gao, Z. Yu, L. Zeng, J. Slanina, et al., Nitrous acid (HONO) and its daytime sources at a rural site during the 2004 PRIDE‐PRD experiment in China, J. Geophys. Res. <strong>113</strong> (2008) D14312.</p><p>[3] T. Wu, Q. Zha, W. Chen, Z. Xu, T. Wang, X. He, Development and deployment of a cavity enhanced UV-LED spectrometer for measurements of atmospheric HONO and NO<sub>2</sub> in Hong Kong, Atmos. Environ. <strong>95</strong> (2014) 544-551.</p><p>[4] L. Meng, G. Wang, P. Augustin, M. Fourmentin, Q. Gou, E. Fertein, T. N. Ba, C. Coeur, A. Tomas, W. Chen, Incoherent broadband cavity enhanced absorption spectroscopy-based strategy for direct measurement of aerosol extinction in lidar blind zone, Opt. Lett. <strong>45 </strong>(2020) 1611-1614.</p>

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