Metals simulation

Overview

From the abstract of Xu et al. [2019]:

Trace metal distributions are of relevance to understand sources of fine particulate matter (PM2.5), PM2.5-related health effects, and atmospheric chemistry. However, knowledge of trace metal distributions is lacking due to limited ground-based measurements and model simulations. This study develops a simulation of 12 trace metal concentrations (Si, Ca, Al, Fe, Ti, Mn, K, Mg, As, Cd, Ni and Pb) over continental North America for 2013 using the GEOS-Chem chemical transport model. Evaluation of modeled trace metal concentrations with observations indicates a spatial consistency within a factor of 2. The spatial distribution of trace metal concentrations reflects their primary emission sources. Crustal element (Si, Ca, Al, Fe, Ti, Mn, K) concentrations are enhanced over the central US from anthropogenic fugitive dust and over the southwestern U.S. due to natural mineral dust. Heavy metal (As, Cd, Ni and Pb) concentrations are high over the eastern U.S. from industry. K is abundant in the southeast from biomass burning. High concentrations of Mg are observed along the coast from sea spray. The spatial pattern of PM2.5 mass is most strongly correlated with Pb, Ni, As and K due to their signature emission sources. Challenges remain in accurately simulating observed trace metal concentrations. Halving anthropogenic fugitive dust emissions in the 2011 National Air Toxic Assessment (NATA) inventory and doubling natural dust emissions in the default GEOS-Chem simulation was necessary to reduce biases in crustal element concentrations. A fivefold increase of anthropogenic emissions of As and Pb was necessary in the NATA inventory to reduce the national-scale bias versus observations by more than 80%, potentially reflecting missing sources.

Reference Xu, J.-W., R.V. Martin, B.H. Henderson, J. Meng, Y.B. Oztaner, J.L. Hand, A. Hakami, M. Strum, and S.B. Phillips, Simulation of airborne trace metals in fine particulate matter over North America, Atmos. Environ., 214, 116883, 2019, DOI: 10.1016/j.atmosenv.2019.116883

List of species

Transported species

Species

Description

Formula

MW (g)

AlF1

not listed

Al

26.98

AlF2

not listed

Al

26.98

AsF1

not listed

As

74.92

AsF2

not listed

As

74.92

CaF1

not listed

Ca

40.08

CaF2

not listed

Ca

40.08

CaC3

not listed

Ca

40.08

CaC4

not listed

Ca

40.08

CdF1

not listed

Cd

112.41

CdF2

not listed

Cd

112.41

FeF1

not listed

Fe

55.84

FeF2

not listed

Fe

55.84

KF1

not listed

K

39.1

KF2

not listed

K

39.1

KC3

not listed

K

39.1

KC4

not listed

K

39.1

MgF1

not listed

Mg

24.31

MgF2

not listed

Mg

24.31

MgC3

not listed

Mg

24.31

MgC4

not listed

Mg

24.31

MnF1

not listed

Mn

54.94

MnF2

not listed

Mn

54.94

NiF1

not listed

Ni

58.69

NiF2

not listed

Ni

58.69

PbF1

not listed

Pb

210.0

PbF2

not listed

Pb

210.0

SiF1

not listed

not listed

28.09

SiF2

not listed

not listed

28.09

TiF1

not listed

Ti

47.87

TiF2

not listed

Ti

47.87