Please use this identifier to cite or link to this item:
http://hdl.handle.net/10397/34466
DC Field | Value | Language |
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dc.contributor | Department of Civil and Environmental Engineering | - |
dc.creator | Pathak, RK | - |
dc.creator | Wu, WS | - |
dc.creator | Wang, T | - |
dc.date.accessioned | 2016-02-29T02:55:20Z | - |
dc.date.available | 2016-02-29T02:55:20Z | - |
dc.identifier.issn | 1680-7316 | en_US |
dc.identifier.uri | http://hdl.handle.net/10397/34466 | - |
dc.language.iso | en | en_US |
dc.publisher | Copernicus Publications on behalf of the European Geosciences Union (EGU) | en_US |
dc.rights | © Author(s) 2009. This is an open access article distributed under the Creative Commons Attribution 3.0 License (https://creativecommons.org/licenses/by/3.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. | en_US |
dc.rights | The following publication: Pathak, R. K., Wu, W. S., and Wang, T.: Summertime PM2.5 ionic species in four major cities of China: nitrate formation in an ammonia-deficient atmosphere, Atmos. Chem. Phys., 9, 1711-1722 is available at https://doi.org/10.5194/acp-9-1711-2009, 2009. | en_US |
dc.title | Summertime PM2.5 ionic species in four major cities of China : nitrate formation in an ammonia-deficient atmosphere | en_US |
dc.type | Journal/Magazine Article | en_US |
dc.identifier.spage | 11487 | en_US |
dc.identifier.epage | 11517 | en_US |
dc.identifier.volume | 8 | en_US |
dc.identifier.doi | 10.5194/acpd-8-11487-2008 | en_US |
dcterms.abstract | Strong atmospheric photochemistry in summer can produce a significant amount of secondary aerosols, which may have a large impact on regional air quality and visibility. In the study reported herein, we analyzed sulfate, nitrate, and ammonium in PM₂.₅ samples collected using a 24-h filter system at suburban and rural sites near four major cities in China (Beijing, Shanghai, Guangzhou, and Lanzhou). Overall, the PM₂.₅ mass concentrations were high (with a mean value of 55–68 gμgm⁻³), which reflects the long-known particulate pollution in China’s large urban centers. We observed very high concentrations of sulfate and nitrate at the Beijing and Shanghai sites, and, in particular, abnormally high levels of nitrate (24-h average concentration up to 42gμgm⁻³ and contributing up to 25% of the PM₂.₅ mass) in the ammonium-poor samples. The Beijing and Shanghai aerosols were characterized by high levels of aerosol acidity (~220–390 nmolm⁻³) and low levels of insitu pH (−0.77 to −0.52). In these samples, the formation of the observed high concentrations of particulate nitrate cannot be explained by homogeneous gas-phase reaction between ammonia and nitric acid. Examination of the relation of nitrate to relative humidity and aerosol loading suggests that the nitrate was most probably formed via the heterogeneous hydrolysis of N2O5 on the surface of the moist and acidic aerosols in Beijing and Shanghai. In comparison, the samples collected in Lanzhou and Guangzhou were ammoniumrich with low levels of aerosol acidity (~65–70 nmolm⁻³), and the formation of ammonium nitrate via the homogeneous gas-phase reaction was favored, which is similar to many previous studies. An empirical fit has been derived to relate fine nitrate to aerosol acidity, aerosol water content, aerosol surface area, and the precursor of nitrate for the data from Beijing and Shanghai. | - |
dcterms.accessRights | open access | en_US |
dcterms.bibliographicCitation | Atmospheric chemistry and physics discussions, 2009, v. 8, p. 11487-11517 | - |
dcterms.isPartOf | Atmospheric chemistry and physics discussions | - |
dcterms.issued | 2009 | - |
dc.identifier.eissn | 1680-7324 | en_US |
dc.identifier.rosgroupid | r35823 | - |
dc.description.ros | 2007-2008 > Academic research: refereed > Publication in refereed journal | en_US |
dc.description.validate | 201811_a bcma | en_US |
dc.description.oa | Version of Record | en_US |
dc.identifier.FolderNumber | OA_IR/PIRA | en_US |
dc.description.pubStatus | Published | en_US |
Appears in Collections: | Journal/Magazine Article |
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Pathak_Summertime_ionic_species.pdf | 395.09 kB | Adobe PDF | View/Open |
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