Characterization of Urban Particulate Air Pollution over

Metropolitan Newark in New Jersey

on the US East Coast

Yuan Gao, Lily Xia, Dawn Roberts-Semple, Rafael Jusino-Astresino, Chris Thuman,

Lu Wang, Nathi Kijpatanasilp

Department of Earth and Environmental Sciences

Rutgers University

Newark, New Jersey USA

.

Objectives:

• To characterize mass-size distributions of ambient aerosol

particles in the polluted urban environment

•To investigate the interactions of chemical species

•To explore the impact of air pollution on biogeochemistry

Methodology:

•Micro-Orifice Uniform Deposit Impactor (MOUDI)

•Inductively coupled plasma mass spectrometry (ICPMS)

•Scanning electron microscope (SEM)

•Ion chromatography (IC)

Newark

Air Measurement Sites

Atlantic ocean

Long Islan

d

New York City

0

10

20

30

40

0.01 0.1 1 10 100

Dp (µm)

dC

/dlo

g(d

Dp)

(µm

m-3

)3)

7/13-7/14

7/24-7/27

8/15-8/18

8/18-8/21

8/21-8/24

8/24-8/27

9/6-9/9

9/9-9/12

9/20-9/22

9/25-9/27

10/12-10/16

12/14-12/18

(Zhao and Gao, Atmospheric Environment, 2008)

Aerosol Mass Size Distributions: Unban Newark

2006

(Xia and Gao, Marine Chemistry, 2010)

Mass Size Distributions at Coastal Site

2009

Mass Size Distributions at High-Traffic Site

Size Distributions: Selected Trace

Elements

Vanadium

Nickle

Size Distributions: Water-Soluble Inorganic and Organic Species

Sulfate and oxalate:

- Dominant peaks are in

submicron meter size ranges

for both,

- positively correlated,

- Consistent with Yu et al,

(2005).

- Both can come from

pollution emissions.

- Both may play important

roles in dust geochemistry;

dust is a source of Fe, a

limiting nutrient in open

ocea.

Evidence of interactions of

soil particles with acific air

pollutants.

(Gao and Anderson,

JGR-Atmospheres, 2001)

Hematite Dissolution in Oxalate Solutions

Dissolution Time (hours)

0 10 20 30 40 50 60

0

2

4

6

8

10

In 25µM oxalate

In background eletrolyte

)b

0 10 20 30 40 50 60

Dis

solv

ed iro

n a

mount

( µm

ol g-1

)

0

2

4

6

8

10Coated with 25mM oxalate

Non-coated )a

pH = 2.4 ± 0.1(Xu and Gao, Applied Geochemistry, 2008)

H+

Inner sphere

coordinated oxygen

Oxygen

C

Molecular structure of inner-sphere surface complexation of Fe(III)-oxalate

Hem

ati

te

So

luti

on

HO – C = O

HO – C = O

Fe

Fe

Implementation of the field/laboratory results from air

pollution studies into global models to gain better

understanding of biogeochemical cycles:

“Aeolian Iron Mobilization by Dust-Acids Interactions and

Its Implication for Soluble Iron Deposition to the Ocean: A

Test Involving Potential Anthropogenic Organic Acidic

Species”

(Luo and Gao, Environmental Chemistry, 2010)

Conclusions:

1. Ambient particulate mass in this region is

dominated by submicron meter particles, likely

formed through heterogeneous reactions,

2. Particulate matter is highly enriched with

chemical elements of non-crustal source,

indicating the level of air pollution,

3. Acidic air pollutants may interact with dust and

then iron, affecting global biogeochemical cycles.

Thank You.Thank You.Thank You.Thank You.