PM estimated from chemistry
Created by: weber-s
It would be important to have the PM mass estimated from the chemistry, following:
PM = [OM] + [EC] + [sea~salt] + [nss-SO_4^{2-}] + [NO_3^-] + [NH_4^+] + [dust] + [non~dust]
EC, NO3, NH4
Directly measured
OM (Lonati et al., 2005; Putaud et al., 2010; Sillanpää et al., 2006, Favez et al. 2011)
We consider a constant value for the OC-to-OM ratio to account unmeasured H, N, O, S
[OM] = 1.8 \times [OC]
nss-SO4 (Seinfeld and Pandis, 1998)
The non sea-salt sulphate.
-
[nss-SO_4^{2-}] = [SO_4^{2-}] - [ss-SO_4^{2-}]
with[ss-SO4] = 0.252\times[Na^+]
so[nss-SO_4^{2-}] = [SO_4^{2-}] - 0.252\times[Na^+]
Sea salt
With the sea water specific ratios:
[ss-K^{+}] = 0.036[Na^{+}]
[ss-Mg^{2+}] = 0.129[Na^{+}]
[ss-Ca^{2+}] = 0.038[Na^+]
[ss-Cl^-] = 1.8[Na^+]
[ss-SO_4^{2-}] = 0.252[Na^+]
Two equation are used, depending on the presence or not of the chloride.
-
without Cl- (Grythe et al., 2014; Putaud et al., 2010):
[sea~salt] = [Na^+]\times(1 + [ss-K^+] + [ss-Mg^{2+}] + [ss-Ca^{2+}] + [ss-Cl^-] + [ss-SO_4^{2-}])
So:[sea~salt] = [Na^+] \times 3.252
-
With Cl- (Putaud et al., 2010):
[sea~salt] = [Cl^{-}] + [Na^{+}]\times(1 + [ss-K^{+}] + [ss-Mg^{2+}] + [ss-Ca^{2+}] + [ss-SO_4^{2-}])
So:[sea~salt] = [Cl^-] + 1.47[Na^+]
Dust
- From soluble
Ca^{2+}
(Putaud et al., 2004a)
[dust] = 5.6 \times [nss-Ca^{2+}]
With[nss-Ca^{2+}]
is estimated thanks to[Na^+]/[ss-Ca^{2+}]
of sea water of 26, so:[nss-Ca^{2+}] = [Ca^{2+}] - [Na^+]/26
.
so[dust] = 5.6 \times ([Ca^{2+}] - [Na^+]/26)
- From metals
- (Malm et al., 1994)
[dust] = 1.16 \times (1.90[Al] + 2.15[Si] + 1.41[Ca] + 2.09[Fe] + 1.67[Ti])
- (Querol et al., 2001; Pérez et al., 2008)
[dust] = Al_2O_3 + SiO_2 + CO_3^{2-} + Ca + Fe + K + Mg + Mn + Ti + P
WithSiO_2
andCO_3^{2-}
determined indirectly thanks to the following empirical relationship:
[SiO_2] = 3 \times [Al_2O_3]
;[Al_2O_3] = 1.89 \times [Al]
;[CO_3^{2-}] = 1.5 \times [Ca]
- (Malm et al., 1994)
Non-dust (Salameh et al. 2015)
Non-dust elements correspond to the sum of the common measured trace elements (i.e., Cu, Ni, Pb, V, Zn) other than geological ones.
[non~dust] = [Cu] + [Ni] + [Pb] + [V] + [Zn]