DOI: 10.1016/j.atmosenv.2015.02.009
Scopus记录号: 2-s2.0-84944940324
论文题名: Characterizing the thermodynamic and chemical composition factors controlling PM2.5 nitrate: Insights gained from two years of online measurements in Hong Kong
作者: Griffith S ; M ; , Huang X ; H ; H ; , Louie P ; K ; K ; , Yu J ; Z
刊名: Atmospheric Environment
ISSN: 0168-2563
EISSN: 1573-515X
出版年: 2015
卷: 122 起始页码: 864
结束页码: 875
语种: 英语
英文关键词: Free NH4 +
; MARGA
; Nitrate episodes
; PM2.5 nitrate characterization
; Seasonal trends
Scopus关键词: Aerosols
; Nitric acid
; Regression analysis
; Storms
; Average concentration
; Chemical compositions
; Free NH<sub>4</sub> <sup>+</sup>
; MARGA
; Nitrate concentration
; Nitric acid concentration
; Photochemical tracers
; Seasonal trends
; Nitrates
; ammonia
; nitrate
; nitric acid
; aerosol
; ammonium
; atmospheric pollution
; chemical composition
; chemical pollutant
; diurnal variation
; nitrate
; nitric acid
; particulate matter
; photochemistry
; regression analysis
; sea salt
; seasonal variation
; thermodynamics
; winter
; aerosol
; Article
; chemical composition
; circadian rhythm
; dust
; environmental temperature
; Hong Kong
; model
; online monitoring
; particle size
; particulate matter
; priority journal
; seasonal variation
; spring
; summer
; thermodynamics
; winter
; China
; Hong Kong
Scopus学科分类: Environmental Science: Water Science and Technology
; Earth and Planetary Sciences: Earth-Surface Processes
; Environmental Science: Environmental Chemistry
英文摘要: In this study, we investigated the seasonal, diurnal, and episodic characteristics of aerosol nitrate concentrations in PM2.5 at a suburban receptor site in Hong Kong using an hourly MARGA sampled dataset. At the site, large spikes in the NO3 - concentration have been observed in all seasons, and are easily overlooked in datasets examining 24 h average concentrations. As a key component to PM2.5, nitrate constituted between 5 and 12% of the mass concentration on average per month, but contributed up to 25% during some episodic cases spanning only a few hours. Seasonal variations of PM2.5 nitrate concentrations at the site were driven by temperature and excess [NH4 +] in the aerosol, defined as the amount of ammonium in excess of that required for satisfying [NH4 +]/[SO4 2-] = 1.5. The vast majority of winter nitrate data was associated with ammonium-rich aerosols ([NH4 +]/[SO4 2-] > 1.5), with the diurnal variation tracking the availability of excess [NH4 +]. Distinctly different than winter conditions, the summer nitrate data was in ammonium-poor regime and tracked nitric acid concentrations, a photochemical tracer. A regression analysis of measured nitrate with the excess [NH4 +] shows good correlation in spring, summer and winter (R2: 0.72-0.81), with slopes greater than 0.7 indicating the majority of excess NH4 + is associated with PM2.5 nitrate. It was found that measured nitrate exceeded excess [NH4 +] in samples of low excess [NH4 +] availability, leading to our finding that nitric acid attaching to sea salt and crustal particles in the fine mode is a non-negligible route (constituting up to ~20% of the PM2.5 nitrate in this study) to assimilate nitrate into the PM2.5 aerosol. Accounting for both this minor route and the ammonia + nitric acid route may prove useful in modeling efforts to capture PM2.5 nitrate measurement fluctuations, particularly during events of a large influx of alkali particles, such as dust storms. © 2015 Elsevier Ltd. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/81411
Appears in Collections: 气候变化事实与影响
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作者单位: Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong; Environmental Central Facility, Institute of Environment, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong; Hong Kong Environmental Protection Department, 47/F, Revenue Tower, 5 Gloucester Road, Wan Chai, Hong Kong
Recommended Citation:
Griffith S,M,, Huang X,et al. Characterizing the thermodynamic and chemical composition factors controlling PM2.5 nitrate: Insights gained from two years of online measurements in Hong Kong[J]. Atmospheric Environment,2015-01-01,122