Effect of ammonia on fine-particle pH in agricultural regions of China: comparison between urban and rural sites
<p>Particle acidity is a fundamental property that affects atmospheric particulate chemistry. Synchronous online monitoring was performed at two urban sites, Zhengzhou (U-ZZ) and Anyang (U-AY), and three rural sites, Anyang (R-AY), Xinxiang (R-XX), and Puyang (R-PY) in Henan Province, during a...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2020-03-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/20/2719/2020/acp-20-2719-2020.pdf |
| _version_ | 1811269269104623616 |
|---|---|
| author | S. Wang L. Wang Y. Li C. Wang W. Wang S. Yin R. Zhang |
| author_facet | S. Wang L. Wang Y. Li C. Wang W. Wang S. Yin R. Zhang |
| author_sort | S. Wang |
| collection | DOAJ |
| description | <p>Particle acidity is a fundamental property that affects atmospheric particulate chemistry. Synchronous online monitoring was performed at two urban
sites, Zhengzhou (U-ZZ) and Anyang (U-AY), and three rural sites, Anyang (R-AY), Xinxiang (R-XX), and Puyang (R-PY) in Henan Province,
during a haze episode to investigate the pH value and its driving factors in the agricultural regions of China. The pH values of particles
calculated by ISORROPIA-II model at rural sites were slightly higher than those at urban sites, with the median (min–max) values of 5.2 (4.8–6.9,
R-PY), 5.1 (4.7–6.5, R-AY), 4.9 (4.1–6.8, R-XX), 4.8 (3.9–5.9, U-AY), and 4.5 (3.8–5.2, U-ZZ). Sensitivity tests show that <span class="inline-formula"><i>T</i>NH<sub><i>x</i></sub></span> (total
ammonium, gas <span class="inline-formula">+</span> aerosol) followed by total sulfate were the most important factors that influenced the predicted pH. Generally, particle pH
increased with a cation increase and decreases in anions, temperature, and relative humidity. Similar pH values (<span class="inline-formula">∼3.0</span>) at the
required <span class="inline-formula">NH<sub><i>x</i></sub></span> concentrations for the five sites indicated that the presence of excess <span class="inline-formula">NH<sub><i>x</i></sub></span> was likely important for the lower acidity
of <span class="inline-formula">PM<sub>2.5</sub></span> during the severe haze episodes in this region. Moreover, the concentrations of excess <span class="inline-formula">NH<sub><i>x</i></sub></span> may drive the higher
pH values at rural sites, because of the higher excess <span class="inline-formula">NH<sub><i>x</i></sub></span> concentrations at rural sites than those at urban sites. The underlying
influence of regional transport on local particle pH cannot be neglected, as it differs the chemical components of <span class="inline-formula">PM<sub>2.5</sub></span> and meteorological
conditions. Air masses transported from rural and agricultural regions may enhance the particle pH value in urban aerosols given the high pH of
particles and high ammonia levels. These results suggest that ammonia is urgently needed to be involved in the regional strategy for the improvement
of air quality in China.</p> |
| first_indexed | 2024-04-12T21:39:04Z |
| format | Article |
| id | doaj.art-9c2c1e1306114f62bc3b178b7734269f |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-04-12T21:39:04Z |
| publishDate | 2020-03-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-9c2c1e1306114f62bc3b178b7734269f2022-12-22T03:15:49ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242020-03-01202719273410.5194/acp-20-2719-2020Effect of ammonia on fine-particle pH in agricultural regions of China: comparison between urban and rural sitesS. Wang0L. Wang1Y. Li2C. Wang3W. Wang4S. Yin5R. Zhang6Research Institute of Environmental Science, College of Chemistry, Zhengzhou University, Zhengzhou, 450001, ChinaDepartment of Environmental Protection of Henan Province, Zhengzhou, 450001, ChinaDepartment of Environment Science and Engineering, Tsinghua University, Beijing 100084, ChinaResearch Institute of Environmental Science, College of Chemistry, Zhengzhou University, Zhengzhou, 450001, ChinaDepartment of Environmental Protection of Henan Province, Zhengzhou, 450001, ChinaResearch Institute of Environmental Science, College of Chemistry, Zhengzhou University, Zhengzhou, 450001, ChinaResearch Institute of Environmental Science, College of Chemistry, Zhengzhou University, Zhengzhou, 450001, China<p>Particle acidity is a fundamental property that affects atmospheric particulate chemistry. Synchronous online monitoring was performed at two urban sites, Zhengzhou (U-ZZ) and Anyang (U-AY), and three rural sites, Anyang (R-AY), Xinxiang (R-XX), and Puyang (R-PY) in Henan Province, during a haze episode to investigate the pH value and its driving factors in the agricultural regions of China. The pH values of particles calculated by ISORROPIA-II model at rural sites were slightly higher than those at urban sites, with the median (min–max) values of 5.2 (4.8–6.9, R-PY), 5.1 (4.7–6.5, R-AY), 4.9 (4.1–6.8, R-XX), 4.8 (3.9–5.9, U-AY), and 4.5 (3.8–5.2, U-ZZ). Sensitivity tests show that <span class="inline-formula"><i>T</i>NH<sub><i>x</i></sub></span> (total ammonium, gas <span class="inline-formula">+</span> aerosol) followed by total sulfate were the most important factors that influenced the predicted pH. Generally, particle pH increased with a cation increase and decreases in anions, temperature, and relative humidity. Similar pH values (<span class="inline-formula">∼3.0</span>) at the required <span class="inline-formula">NH<sub><i>x</i></sub></span> concentrations for the five sites indicated that the presence of excess <span class="inline-formula">NH<sub><i>x</i></sub></span> was likely important for the lower acidity of <span class="inline-formula">PM<sub>2.5</sub></span> during the severe haze episodes in this region. Moreover, the concentrations of excess <span class="inline-formula">NH<sub><i>x</i></sub></span> may drive the higher pH values at rural sites, because of the higher excess <span class="inline-formula">NH<sub><i>x</i></sub></span> concentrations at rural sites than those at urban sites. The underlying influence of regional transport on local particle pH cannot be neglected, as it differs the chemical components of <span class="inline-formula">PM<sub>2.5</sub></span> and meteorological conditions. Air masses transported from rural and agricultural regions may enhance the particle pH value in urban aerosols given the high pH of particles and high ammonia levels. These results suggest that ammonia is urgently needed to be involved in the regional strategy for the improvement of air quality in China.</p>https://www.atmos-chem-phys.net/20/2719/2020/acp-20-2719-2020.pdf |
| spellingShingle | S. Wang L. Wang Y. Li C. Wang W. Wang S. Yin R. Zhang Effect of ammonia on fine-particle pH in agricultural regions of China: comparison between urban and rural sites Atmospheric Chemistry and Physics |
| title | Effect of ammonia on fine-particle pH in agricultural regions of China: comparison between urban and rural sites |
| title_full | Effect of ammonia on fine-particle pH in agricultural regions of China: comparison between urban and rural sites |
| title_fullStr | Effect of ammonia on fine-particle pH in agricultural regions of China: comparison between urban and rural sites |
| title_full_unstemmed | Effect of ammonia on fine-particle pH in agricultural regions of China: comparison between urban and rural sites |
| title_short | Effect of ammonia on fine-particle pH in agricultural regions of China: comparison between urban and rural sites |
| title_sort | effect of ammonia on fine particle ph in agricultural regions of china comparison between urban and rural sites |
| url | https://www.atmos-chem-phys.net/20/2719/2020/acp-20-2719-2020.pdf |
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