A study of water-soluble inorganic ions in size-segregated aerosols in atmospheric pollution episode

Abstract

Particulate matter, the main pollutant in the atmospheric environment of the Santiago city in winter, was analyzed by means of the major water-soluble ionic species obtained under critical episodes of pollution in 2003. The particulate matter samples were collected using the Micro-Orifice uniform deposit impactors, with eight impactor stages connected in series, and the ionic species in particulate matter samples at each stage was analyzed by ion chromatography. While sulfate ion and nitrate ion showed bi-modal distributions, peaking in the fine and coarse mode, ammonium ion displayed a bi-modal size distribution, peaking in the fine and ultra fine mode. The equivalent concentration ratio of ammonium to sulfate was 2.03 ± 0.09, indicating the complete neutralization of sulfuric acid by ammonia. The excess ammonium ion was associated to nitrate ion. The study of the size distribution of water-soluble inorganic ions in particulate matter supports the notion that secondary aerosols play a significant role in the urban atmosphere.

Determination of aerosol deliquescence and crystallization relative humidity for energy saving in free-cooled data centers

“…If aerosol deposits on electronic circuitry and the ambient RH exceeds the aerosol DRH, or remains higher than the aerosol CRH (while decreasing from above the DRH), the water-soluble ionic compounds are dissociated and the aerosol is then electrically conductive and corrosive (Song et al 2013;Shehabi et al 2008;Tencer 2008;Syed 2006;Yang et al 2006;Lobnig et al 1994). This behaviour constitutes a serious risk in DCs because, as Leiva et al (2013) have shown, atmospheric pollution is often related with high concentrations of water-soluble inorganic ions.…”

Electrochemical detection of nitrate in PM2.5 with a copper-modified carbon fiber micro-disk electrode

“…Airborne particulate matter (PM) is a complex mixture of small particles and liquid droplets suspending in the atmosphere that can be emitted directly as primary PM or formed through gas-to-particle partitioning of semi-volatile products as secondary PM [1,2]. In recent years, PM has received growing attention due to its significant influence on global climate, human health, air quality deterioration and visibility reduction [3].…”

“…Water-soluble ions often account for a major and most influential fraction of PM 2.5 [7,8]. Nitrate is one of the major constituents of the secondary water-soluble ions in PM 2.5 [1,9,10], which is formed primarily by photochemical reactions of the gaseous precursorsnitrogen oxides (NO X ) [11][12][13]. Nitrate plays important roles in light extinction effect, and is one of the important factors affecting the visibility [14,15].…”