Chapter 67
Characteristics and Source Contribution
of Particulate Matters Acidity in City
of Atlanta
Yu Qian and Armistead G. Russell
Abstract Aerosol acidity plays an important role by affecting aerosol formation,
concentration, human health, and nutrient bioavailability. This study used thermodynamic model (ISORROPIA-II) and measurement data in Atlanta, GA, USA from
2009 to 2013. Aerosol pH in this research domain kept low (average 2.61) and did not
change much over the past decade with the SO 2 emissions reduction. But the trend
still shows significant seasonal patterns (high in the winter and low in the summer)
and spatial variation (higher in urban and lower in rural area). Model performance
were evaluated by comparing estimated and observed NH 3 gas phase partitioning.
Also based on the source apportionment results for the same domain, multiple-linearregression models were developed to show the source impacts on fine particle pH.
With strong correlations (average R
2
= 0.52), in most cases, models indicate vehicles have the largest positive impact on pH and ammonia bisulfate contribute most
negative impact on pH, even though specific results are different for different seasons
and locations.
67.1 Introduction
Particles with fine diameter, such as PM 2.5 , contain various components [10], as well
as certain amount of liquid water [1]. Observation from the Southeastern US shows
that ammonium, nitrate, and sulfate are major inorganic ions, which are closely
related to particle acidity. Other species such as Na, Cl, Ca, Mg, etc. have relatively
low proportion. Particle pH is calculated as the logarithmic scale of Hydronium ion
(H 3 O
+ , simplified as H
+ ). H
+ substantially plays important roles in aerosol formation
and chemical pathways. The SOA production rate from different precursors can
Y. Qian (B) · A. G. Russell
School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA
30332, USA
e-mail: legendq@gatech.edu
A. G. Russell
e-mail: ted.russell@gatech.edu
© Springer Nature Switzerland AG 2020
C. Mensink et al. (eds.), Air Pollution Modeling and its Application XXVI,
Springer Proceedings in Complexity,
https://doi.org/10.1007/978-3-030-22055-6_67
421
Characteristics and Source Contribution
of Particulate Matters Acidity in City
of Atlanta
Yu Qian and Armistead G. Russell
Abstract Aerosol acidity plays an important role by affecting aerosol formation,
concentration, human health, and nutrient bioavailability. This study used thermodynamic model (ISORROPIA-II) and measurement data in Atlanta, GA, USA from
2009 to 2013. Aerosol pH in this research domain kept low (average 2.61) and did not
change much over the past decade with the SO 2 emissions reduction. But the trend
still shows significant seasonal patterns (high in the winter and low in the summer)
and spatial variation (higher in urban and lower in rural area). Model performance
were evaluated by comparing estimated and observed NH 3 gas phase partitioning.
Also based on the source apportionment results for the same domain, multiple-linearregression models were developed to show the source impacts on fine particle pH.
With strong correlations (average R
2
= 0.52), in most cases, models indicate vehicles have the largest positive impact on pH and ammonia bisulfate contribute most
negative impact on pH, even though specific results are different for different seasons
and locations.
67.1 Introduction
Particles with fine diameter, such as PM 2.5 , contain various components [10], as well
as certain amount of liquid water [1]. Observation from the Southeastern US shows
that ammonium, nitrate, and sulfate are major inorganic ions, which are closely
related to particle acidity. Other species such as Na, Cl, Ca, Mg, etc. have relatively
low proportion. Particle pH is calculated as the logarithmic scale of Hydronium ion
(H 3 O
+ , simplified as H
+ ). H
+ substantially plays important roles in aerosol formation
and chemical pathways. The SOA production rate from different precursors can
Y. Qian (B) · A. G. Russell
School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA
30332, USA
e-mail: legendq@gatech.edu
A. G. Russell
e-mail: ted.russell@gatech.edu
© Springer Nature Switzerland AG 2020
C. Mensink et al. (eds.), Air Pollution Modeling and its Application XXVI,
Springer Proceedings in Complexity,
https://doi.org/10.1007/978-3-030-22055-6_67
421