The aerosol composition and the particle
size distribution of ionic species can be used to define sources. Table 5
present the concentration of ionic species: anions (F-, Cl-,
NO2-, Br-, NO3- , PO43-
and SO42-) and cation (Li+, Na+, NH4+,
K+, Mg2+ and Ca2+) into different fractionated
size ranges PM0.32 (0.19-0.32 µm), PM1 (0.32-1 µm), PM3.2
(1-3.2 µm) and PM18 (3.2-18 µm) of aerosol particles.
The Cl-, SO42-, Na+,
Mg2+ and Ca2+ were observed major chemical composition of
nanoparticles. The concentration of anions Cl- (2358 µg/L), SO42-
(2190 µg/L), and cations Mg2+ (596 µg/L), Na+ (1527
µg/L), Ca2+(2590 µg/L) was found maximum corresponding to PM0.32(Nano
fractionated particles). While the concentration of NO3-(1220
µg/L), NO2- (2260 µg/L) and K+(360 µg/L) found
maximum corresponding to PM3.2. The minimum concentration of anions
and cations were varied corresponding to different fractionated size ranges. The
concentration of nitrate and ammonium ions in PM0.32 were
considerably lower than in PM1 and PM3.2, respectively
suggesting that they accumulate mostly in the upper part of submicron fraction.
Previous study also showed concentration of nitrate and ammonium ions were maximum
in submicron size range (0.45 -1.09 µm) of aerosols Terzi et al., 2007; Rogula.
The concentration of F-, Br-,
PO43- and Li+ observed below detection limit
(< 0.1ppm). The abundance of chemical species SO42-, NO3-, Mg2+, Na+, and Ca2+into the nano-sized particles (i.e., <1 micron) shows the good agreement with correlation study between nanoparticles and SO2, NOx and CO. The SO42- and NO3- noted that the major secondary aerosol particles reside the atmosphere for long time due to their physical properties Samara et al., 2016 also known to be produced largely by the gas phase reaction of primary combustion which could be from traffic emission, shipping emission, industrial related to SO2 and NOx Hu et al., 2008Seinfeld and Pandis, 2016. The TOC concentration dominant in PM0.32 size fractionated range and PM1 while were not observed intoPM3.2 and PM18 size fraction. The observance of TOC concentration, indicate the contribution of carbonic compounds to formation of nanoparticles, validated by morphology of particles. The high concentration of Cl? into PM0.32 and observance in each fractionated size ranges in this study, which may be attributed both sea source and anthropogenic emission. The loss of chloride from sea-salt particles could be attributed to the reactions of NaCl particles with HNO3 and H2SO4 with preceding of HCl (Horemans et al., 2009; Pey et al., 2009). In addition, the reaction between NaCl and N2O5 can also be responsible for chloride depletion and also released Cl2 and HOCl (Yao and Zhang, 2012). The importance of chemical reactions to chloride depletion depends on several factors such as the size and acidity of aerosol and concentrations of gaseous pollutants (HNO3, NOx, SO2, etc).