Kagawa Contents 2012

7/28/2019 Kagawa Contents 2012

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Characterization of inorganic species and carboxylic acids in

ambient aerosol during dry season in the Chiang Mai Basin,

ThailandA. Chotruksa1, Hsin-ChingWu, Y.I. Tsai2, K. Sopajaree1

1. Department of Environmental Engineering, Chiang Mai University, Chiang Mai 50200, Thailand2. Department of Environmental Engineering and Science, Chia Nan University of Pharmacy and

Science, 60, Sec. 1, Erh-Jen Rd., Jen-Te, Tainan 717, Taiwan

Abstract

Aerosol samples for PM10 were collected during dry season of February and

April at two sites different sampling locations in Chiang Mai basin, Thailand.

Concentrations of water-soluble inorganic species and carboxylic acids in PM10 were

quantified. Oxalic acid was the dominant dicarboxylic acid species, follow by maleic

acid. Mass ratio of acetic to formic acids (A/F) > 1 was often used to demonstrate theprimary source by wood burning or vehicular emission, and it indicated that the

contribution of primary sources was higher at suburban site than urban site.

Carboxylic acid concentration during the PM10 episode is higher than that during

non-episodic period. The most significant contribution to PM10 in Chiang Mai basin

was from the photochemical formation of secondary aerosols and biomass burning.

Keywords: Carboxylic acids; Maleic acid; A/F ratio

Table 1. Title

Figure 1. title

0

2

4

6

8

10

12

0 2 4 6

X ( unit)

Y

(unit)

s rac


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1. Introduction

Particulate matter is the major air pollutant of atmospheric aerosols and can be

the predominant constituent of find atmospheric particles, are important organics

resulting from the marine pathway, biomass burning, agriculture burning, automotiveexhaust emission and anthropogenic emission (Khwaja, 1995; Chebbi and Carlier,

1996; Souza et al., 1999; Hsieh et al., 2008; Lee et al., 2008; Zhang et al., 2008;).

These emissions are impacts on regional air quality and visibility, ecosystems and

human health, and climate change (Khwaja, 1995; Souza et al., 1999; Tsai, 2005).

Low molecular weight carboxylic acids are ubiquitous and important

components in the tropospheric aqueous and gaseous phases, and in aerosol particles

(Chebbi and Carlier, 1996). Carboxylic acids in the particle phase accounted for a

small fraction of the organic carbon. Results indicated that photochemical processes

and anthropogenic emissions such as automobile exhaust are major sources of

atmospheric carboxylic acids (Khwaja, 1995). Monocarboxylic acids were observedwith a daytime maximum and a nighttime minimum (Khawaja, 1995; Chebbi and

Carlier, 1996). Formic and acetic acids constitute the most abundant carboxylic acids

in the global troposphere (Khwaja, 1995; Souza et al., 1999). During daytime,

vehicular emission appeared to be the primary source of acetic acid, whereas formic

and pyruvic acids should be formed photochemically (Souza et al., 1999). In addition,

formic acid is one of the photochemical oxidation products from volatile organic

compounds (VOC), the results show that 80-100% of formic acid stems from biogenic

VOC emitted from terrestrial sources (Glasius et al., 2000). Besides that, dicarboxylic

acids are among the most abundant organic constituents of ambient particulate matter

(Ray and McDow, 2005). Dicarboxylic acids are widely present in the urban, rural

and marine atmosphere. Oxalic acid was found as the most abundant species,

followed by succinic and malonic (Khawaja, 1995; Chebbi and Carlier, 1996; Ho et

al., 2006; Hsieh et al., 2008; Tsai et al., 2008; Hsieh et al., 2009).

The biomarker levoglucosan (1,6-anhydro--D-glucopyranose) is formed as a

result of the thermal breakdown alteration of the cellulose, accompanied by generally

lesser amounts of straight-chain, aliphatic and oxygenated compounds and terpenoids

present in the vegetation subjected to biomass burning. The biopolymer (cellulose)

decomposes during combustion, yielding a tarry material containing anhydrosugars

(Simoneit et al.,1999; Santos et al., 2002; Lee et al., 2008). This compound, together

with other thermal decomposition products from cellulose and hemicelluloses (e.g.manosan, galactosan and levoglucosan) were utilized as tracers for biomass burning

(Santos et al., 2002; Schmidl et al., 2008; Bari et al., 2009; Caseiro et al., 2009; Fabbri

et al., 2009). It has a large impact on the biomass burning attribution as it is emitted

at high concentrations. (Simoneit et al., 1999; Jordan et al., 2006; Zhang et al., 2008).

Moreover, Jordan et al., (2006) reported that woodsmoke was estimated to comprise

about 95% of wintertime air pollution in Launceston, and the resulting average

levoglucosan woodburning emission factor of around 140 mg g-1 particulate matter

was found to be consistent with previously determined woodheater emissions.


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2. Methodology

2.1 Sampling

Aerosol samples were collected on a 47-mm Teflon filters(Zefluor, Pall) using a

Ecotech MicroVol 1100 Particulate Sampler with a total flow rate of 3 L min-1,

between 2 February-2 April 2010, at two sites: Facultyof Architecture Chiang MaiUniversity (CMU; Located at latitude 18o4754.90 N and longitude 98o5655.75 E),

set at a height of 12 m above ground, located in the urban area, has little traffic, near

Suthep mountain and excellent ventilation; TOT Public Company Limited (TOT;Located at latitude 18o 41 40.04 N and longitude 99o2' 59.45 E), set at ground

level, with heavy traffic highways and close to the industrial zone. Each sampling

collected two sets of aerosol samples were collected daily, one from 7 am to 7 pm

(12 h: daytime) every 3 days and another from 7 pm to 7 am (12 h: nighttime)

every 3 days.

The geographic locations of air samplings are shown in Figure 2.1.

Figure 2.1 Map of Chiang Mai province area identifying the location of air sampling

sites.

2.2 Sampling handing

Before and after sample collection, filters were conditioned at 405% RH for

24 hours and subsequently weighed at 503% RH using a Mettler Toledo AT261

analytical balance with a sensitivity of 10 g and a Sartorius CP2P analytical balance

with a sensitivity of 1 g. All weight measurements were repeated three or more times

and the Shewart control procedures were followed to ensure reliability. Additionally,

blank filters were prepared by purging in 99.995% pure nitrogen for 30 seconds and

then processed as for sample-containing filters.

2.3 Chemical analysis and quality assurance

CMU site

TOT site


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The sample-containing filters, unexposed blanks will be stored in petri dishes

placed inside an unlit refrigerator below -18C to prevent loss of semi-volatile species,

especially carboxylic acids and ammonium nitrate. For analyzing carboxylic acid,

cations and anions, the filter paper will be placed in a PE bottle, 10.0 mL of deionized

water (resistivity >18.0 M cm-1 at 25C, Barnstead) will be added and the contents

will be shaken (Yihder TS-500 Shaker) in an unlit refrigerator at 4 C for 90 min toprevent the decomposition of the extracted carboxylic acid species. The liquid is then

filtered through a 0.2 m ester acetate filter and the aqueous filtrate will be is

characterized using IC, following a slightly modified version of the method of Hsieh

et al. (2008).

The ion chromatography system (IC) model DX-600, Dionex is equipped with a

gradient pump (Model GP50), an ASRS-Ultra anion self-regenerating suppressor, a

conductivity detector (CD25), a Spectrasystem automated sampler (AS3500) with 2

mL vials, and a Teflon injection valve using a 1000 L sample loop, in combination

with analytical column and Ion Pac AG11-HC, AS-11-HC (4 mm), eluent for the DI

water (deionized), 5 mM NaOH, 100 mM NaOH and 100% MeOH gradient elution

method to conduct analysis. The flow rate is maintained at 2.0 mL min-1 during the

carboxylic acid analyses, which Ion Chromatography Dionex DX-600 gradient elution.

This method allows for the analysis of acetic acid, formic acid, glutaric acid, succinic

acid, malic acid, malonic acid, tartaric acid, maleic acid, fumaric acid, oxalic acid,

phthalic acid and citric acid in the aerosol samples.

Additionally, 1000 L of the aqueous extract will be injected into IC Model

Dionex ICS-2500 using 9 mM Na2CO3 eluent at a flow rate of 1.4 mL min-1.

Concentrations of the separated inorganic species including Cl-, NO3- and SO4

2-, are

determined in analytical column RFIC

TM

Ion Pac AS14A, AG14A (4 mm). Cationsystem to IC Model Dionex ICS-1000, AS1000, analytical column and Ion Pac

CG12A, CS12A (4 mm), injection volume 25 L and an isocratic 20 mM MSA

(CH4O3S) eluent at a flow rate of 1.0 mL min-1 will be used for determination of

cations, including Na+, NH4+, K+, Mg2+ and Ca2+. Department of anhydrosugars

(levoglucosan, mannosan and galactosan) are to IC Model Dionex ICS-2500 (ED50,

GP50, AS50), analytical column and Carbo PacTM MA1 (4 mm), flow rate 0.4

mL/min, injection volume 0.2 mL, eluent conducted for the 400 mM NaOH

component analysis.

All reagents are of analytical grade, obtained from Merck (Darmstadt, Germany),

and are used without further purification. The solutions will be prepared usingdeionized water from which organic carbon had been removed and the detection

limits corresponded to 10-50 ng for the carboxylic acids investigated.

2.4 Other data

Ambient air quality data were obtained from the Thailand Pollution Control

Department (PCD), information was obtained on Air Quality data from 2 February to

2 April 2010 over Chiang Mai province, Thailand. The Air Quality was particularly

useful for observing pollutant concentrations. Moreover visibility was obtained from

Thai Meteorological Department during sampling.

Site meteorological data (Table 1) confirm designations of each period of


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study. In this study to explain two period was the non-episodic pollution period

(PM10120 g m

-3). During the PM10

episode and non-episodic pollution period, average PM10 concentrations were 156.88

38.10 and 78.71 20.42 g m-3, respectively. The data shows concentrations of

pollutant, especially O3, SO2, NO2, NOx, NO and CO, which represent traffic

emission, were higher during the PM10 episode. Moreover, higher temperature, lowerrelative humidity and lower wind speed during the PM10 episode to be high O3 is due

to lower visibility, higher PM10 and increase pollutant of these periods.

3. Results and discussion

3.1 Carboxylic acids

The water soluble organic acids, accessible by ion chromatography, were

monocarboxylic acids (acetic acid and formic acid), dicarboxylic acids and

tricarboxylic acids. The most abundant carboxylic acids at the CMU site (urban) and

TOT site (suburban) was oxalic acid, follow by acetic acid and maleic acid during the

PM10 episode, while during non-episodic pollution period acetic acid was the most

abundant species, follow by oxalic acid and maleic acid (see Figure 1). Sources of

maleic acid from wood and coal burning was the dominant source in the Christchurch

wintertime (Wang et al.,2004) indicated that source in Chiang Mai may be from wood

burning.

During the PM10 episode, carboxylic acids higher during daytime indicating

that carboxylic formed by photochemical reaction and/or emitted directly by fossil

fuels and biomass burning processes more frequency at daytime. At the CMU site the

concentrations of carboxylic acids higher than TOT site. Moreover, Formic-to-acetic

acid ratio (A/F) (see Tables 2 and 3) was used to distinguish the primary (A/F>1) andthe secondary (A/F


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3.3 Relationships among chemical species during non-episodic pollution period

and PM10 episode at TOT site

Varimax-rotated principal component analysis was used in this study to

investigate the various sources of air pollution. Table 4 lists the Factors results fordaily PM10 chemical composition, air pollutants and relative humility temperature and

wind speed during non-episodic pollution and PM10 episode at TOT site. During

non-episodic pollution, there were six factors with eigenvalues exceeding 1.0

indicating that these factors had a significant influence on the air quality of this

period. They account for 88.9% of explained variance of air quality. The variance that

can be explained by the first Factor (Factor 1) is 30.1% and the significant component

loading (component loading 0.7) is mainly related primary source species including

acetic and fumaric acid. Additionally during non-episodic pollution sea salts, i.e.

sodium and calcium but at Chiang Mai is more than 600 km inland of the shore may

be source from some industrial. And, ammonium from traffic emission has strong

correlation. Hence, as mentioned in the literature (Hsieh et al., 2008; Tsai and Cheng,2004; Tsai and Chen, 2006). Factor 2, which explain source from photochemical

oxidation of oxalic and succinic acid. Good correlation with potassium and sulfate

indicated that source from biomass or traffic emission. Glutaric, maleic and citric acid

and nitrate are strongly positively correlated in Factor 3, indicated that source from

traffic emission. In Factor 4, good correlation with calcium and tartaric acid, showing

that the contributed from traffic and coal combustion. During PM10episode, calcium,

nitrate and acetic acid in Factor 1 display significant component loading confirming

that primary source from traffic emission. Factor 2, tartaric, maleic and fumaric acid

contributed from traffic emission or coal burning. In Factor 3, glutaric, succinic and

malonic show component loading indicating the influence of photochemical or

secondary source from traffic. Factor 7, malic acid high correlation with phthalic acid

implies that the atmospheric environment is affected by emission from biomass

burning activities. Sodium and chloride in Factor 8 showing that the sea breeze to

contribute to the atmosphere or may be from industrial area.

4 Conclusion

This study has investigated the water-soluble carboxylic acid species in PM10

aerosols in Chiang Mai basin. Some principal conclusions were presented as follows:

(1)The most abundant carboxylic acids at the CMU site (urban) and TOT site


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(suburban) was oxalic acid, follow by acetic acid and maleic acid during the

PM10 episode, while during non-episodic pollution period acetic acid was the

most abundant species, follow by oxalic acid and maleic acid

(2)Acetic-to-formic acid ratio (A/F) > 1 was often used to distribute fromprimary source by wood burning or vehicular emission, and it indicated that

the contribution of primary sources from biomass burning, was higher at TOTsite than CMU site.

(3)During the PM10 episode, carboxylic acids higher during daytime indicatingthat carboxylic formed by photochemical reaction and/or emitted directly by

fossil fuels and biomass burning processes more frequency at daytime.

(4)At TOT site, most abundant source emission from traffic and coal burning.

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Table 1 Meteorological and related air pollution information during the period of

study at the suburban site

ParameterDuring non-episodic

pollution

During the PM10episode

Mean SD Mean SD

Temperature ( C) 25.61 3.38 28.49 2.65

Relative humidity (%) 54.07 7.88 52.11 7.09

Pressure (mmHg) 731.17 1.56 731.92 1.38

Visibility (km) 8.21 1.24 5.80 1.38

Prevailing wind

directionNW-N NW-N

Wind speed 1.68 0.54 1.60 0.43

PM10 (g m-3) 78.71 20.42 156.88 38.10

O3 (ppb)a

49.06 29.42 90.86 31.21SO2 (ppb) 0.70 0.41 1.53 0.46

NO2 (ppb) 14.64 5.34 14.69 3.12

NOx (ppb) 19.78 7.44 17.94 2.56

NO (ppb) 5.16 2.61 3.30 1.11

CO (ppm) 0.78 0.19 1.11 0.26a Average maximum hourly ozone in each sampling sets.


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Table 2 Mean (SD) chemical composition of PM10 aerosol and ratios of species nighttime/daytime concentrations during non-episodic pollution

period and PM10 episode at CMU site.

Species

CMU site

During non-episodic pollution period During PM10 episode

Mean SD Mean SD

PM10 (g m-3) 58.08 30.85 1.04 1.10 139.56 13.97 0.921 0.458

Inorganic species (g m-3) 7.15 4.09 1.54 0.94 15.12 4.41 0.83 0.93

Sodium 0.48 0.49 1.49 1.35 1.19 1.04 0.881 0.886

Ammonium 1.23 0.89 1.57 1.85 2.71 0.79 1.109 2.032Potassium 0.89 0.57 1.40 1.10 2.31 0.56 1.043 2.075

Magnesium 0.31 0.30 2.27 3.78 0.73 0.28 1.111 1.172

Calcium 0.92 0.61 1.11 2.03 1.88 0.67 0.633 0.418

Chloride 0.25 0.15 1.22 0.80 0.55 0.74 0.296 0.050

Nitrate 1.22 1.01 1.81 2.33 2.10 1.94 0.533 0.222

Sulfate 1.84 1.36 1.45 1.24 3.65 1.03 1.062 2.455

Carboxylic acids (ng m-3) 1109.30 480.28 1.05 0.60 2148.35 1010.58 0.69 0.53

Acetic acid 325.14 274.39 1.71 1.47 443.16 489.92 0.257 0.373

Formic acid 55.28 39.60 1.84 2.29 148.07 156.73 0.555 0.403

Glutaric acid 18.59 27.93 0.40 0.30 57.87 32.53 0.843 0.938

Succinic acid 36.40 37.55 0.68 0.72 105.73 51.68 0.747 0.836

Malic acid 61.51 55.87 1.23 1.46 144.66 70.10 0.685 0.593

Malonic acid 48.76 27.43 0.88 0.86 99.54 32.50 0.731 0.988Tartaric acid 39.12 60.19 0.55 0.26 54.33 23.80 1.044 1.953

Maleic acid 141.13 153.71 0.96 0.95 151.91 194.25 0.828 0.339

Fumaric acid 9.38 7.52 0.77 0.64 27.38 13.92 0.706 1.235

Oxalic acid 284.32 207.48 1.17 1.13 758.87 198.82 0.865 1.264

Phthalic acid 29.06 24.01 1.83 1.34 51.39 35.44 0.843 1.281

Citric acid 60.59 76.16 0.61 0.28 105.43 179.31 0.131 0.072

Acetic/Formic 5.88 6.93 2.99 3.13

Malonic/Succinic 1.34 0.73 0.9 0.6

daytime

nighttime

daytime

nighttime


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Table 3 Mean (SD) chemical composition of PM10 aerosol and ratios of species nighttime/daytime concentrations during non-episodic pollution

period and PM10 episode at TOT site.

Species

TOT site

During non-episodic pollution period During PM10 episode

Mean SD Mean SD

PM10 (g m-3) 76.54 25.86 0.82 0.57 141.21 17.85 0.97 1.20

Inorganic species (g m-3) 7.14 3.76 1.66 5.05 13.18 4.41 0.96 1.02

Sodium 0.50 0.74 2.67 12.22 0.64 0.75 0.83 2.05

Ammonium 0.84 0.58 1.41 2.12 2.01 0.70 0.99 0.94Potassium 0.75 0.36 1.33 1.23 1.87 0.54 0.99 0.76

Magnesium 0.25 0.10 1.01 0.72 0.55 0.26 0.69 0.65

Calcium 1.24 0.47 0.89 0.55 2.05 0.83 0.84 0.30

Chloride 0.39 0.52 2.78 12.10 0.46 0.49 1.48 3.20

Nitrate 1.94 1.53 1.71 1.81 2.39 2.08 0.84 0.27

Sulfate 1.22 0.79 1.48 1.47 3.20 1.05 1.05 1.73

Carboxylic acids (ng m-3) 1068.12 431.43 1.37 1.24 1783.01 782.56 0.81 0.41

Acetic acid 408.24 265.03 1.49 3.73 467.98 341.65 0.54 0.46

Formic acid 43.64 31.69 1.29 2.71 54.13 35.99 1.17 1.31

Glutaric acid 8.45 7.35 1.73 2.50 37.75 24.60 0.99 0.87

Succinic acid 22.86 16.44 0.76 0.70 70.07 32.37 0.88 1.38

Malic acid 52.23 41.67 1.48 2.83 107.25 70.79 0.70 0.51

Malonic acid 39.58 14.19 0.78 1.30 78.09 23.78 0.97 0.93Tartaric acid 28.51 37.66 0.56 0.47 46.87 28.42 0.98 0.96

Maleic acid 176.28 161.99 3.49 3.94 210.41 475.75 0.38 0.15

Fumaric acid 5.53 3.60 1.18 0.92 18.99 15.97 0.87 0.71

Oxalic acid 215.62 76.31 1.10 0.82 591.81 174.10 0.99 0.73

Phthalic acid 21.75 20.64 0.97 0.75 35.93 26.03 0.72 1.26

Citric acid 45.43 47.78 1.66 1.42 63.72 144.17 0.45 0.23

Acetic/Formic 9.35 8.36 8.65 9.49

Malonic/Succinic 1.73 0.86 1.11 0.73

daytime

nighttime

daytime

nighttime


15/16

Table 4 Varimax-rolated principal component loading of daily PM10 chemical species pollutants and relative humidity, temperature and wind speed

during non- episodic pollution period and PM10 episode

TOT during non-episodic pollution period TOT during the PM10 episode

Factor1 Factor2 Factor3 Factor4 Factor5 Factor6 Factor1 Factor2 Factor3 Factor4 Factor5 Factor6 Factor7 Factor8

Variance

PM10 0.03 0.76 -0.14 0.41 0.34 0.00 -0.08 -0.30 0.07 -0.18 0.20 -0.85 0.07 0.08

Sodium 0.94 0.03 -0.01 -0.14 0.12 0.11 -0.04 0.10 0.14 0.07 0.12 0.00 0.10 0.92

Ammonium 0.72 0.17 0.52 0.26 -0.18 0.27 0.49 -0.20 0.21 -0.48 0.40 0.47 0.06 0.17

Potassium 0.37 0.90 0.02 -0.08 -0.01 -0.08 0.15 -0.45 0.55 -0.16 0.26 0.02 0.06 0.45

Magnesium 0.39 0.33 0.33 0.65 -0.14 0.08 0.64 -0.23 0.45 0.14 0.39 0.16 0.26 -0.13

Calcium 0.14 0.43 0.31 0.74 -0.03 0.15 0.90 -0.11 0.22 -0.10 0.15 0.03 -0.08 -0.17

Chloride 0.95 0.21 0.14 -0.05 0.00 0.10 -0.12 0.10 0.26 -0.27 -0.02 -0.06 0.08 0.88Nitrate 0.26 0.11 0.88 0.27 -0.22 -0.03 0.85 0.10 0.32 -0.28 -0.04 -0.05 -0.12 -0.15

Sulfate 0.14 0.84 0.30 0.02 -0.32 0.09 0.25 -0.20 -0.16 -0.63 0.35 0.01 -0.31 0.31

Acetic acid 0.76 0.33 0.06 0.04 0.05 -0.40 0.84 0.00 -0.08 0.20 0.24 0.11 -0.18 0.23

Formic acid 0.41 0.32 0.61 0.11 0.24 0.05 -0.38 0.38 0.60 -0.03 0.08 0.22 -0.10 0.24

Glutaric acid -0.27 0.25 0.82 0.08 0.13 -0.15 0.05 0.54 0.71 0.07 -0.12 0.03 0.26 0.25

Succinic acid -0.40 0.76 -0.28 0.16 0.32 -0.15 0.21 0.11 0.90 0.01 0.02 -0.19 0.10 0.14

Malic acid 0.22 0.05 0.04 -0.18 0.88 -0.01 -0.04 0.26 0.03 0.13 -0.13 -0.18 0.82 0.20

Malonic acid -0.45 0.28 0.11 0.62 0.22 -0.43 0.31 0.04 0.90 0.04 0.09 0.05 0.06 0.13

Tartaric acid -0.11 -0.25 0.48 0.78 -0.08 0.05 -0.09 0.71 0.43 0.15 -0.29 -0.14 -0.22 0.05

Maleic acid 0.02 0.00 0.91 -0.15 -0.13 0.12 -0.07 0.95 0.06 0.06 0.10 0.11 0.08 0.05

Fumaric acid 0.76 0.29 -0.06 0.12 0.26 -0.04 0.22 0.78 -0.02 -0.25 0.18 0.13 0.10 0.17

Oxalic acid 0.34 0.90 0.11 0.14 0.04 -0.04 0.25 -0.58 0.61 0.02 0.25 0.18 0.07 0.05

Phthalic acid -0.13 0.04 -0.10 -0.17 -0.01 -0.89 -0.34 -0.08 0.40 0.11 0.23 0.15 0.73 0.07

Citric acid 0.16 -0.26 0.83 0.27 0.26 0.12 -0.07 0.96 0.07 0.10 0.00 0.10 0.07 0.01

RH 0.30 -0.35 0.51 -0.55 0.18 -0.10 -0.20 -0.22 -0.02 0.11 -0.85 0.19 0.28 -0.08

Temp. 0.12 -0.02 -0.43 0.68 -0.19 0.36 0.15 -0.08 0.10 0.19 0.89 0.00 0.23 0.06

Wind speed 0.67 -0.55 0.00 0.21 0.18 0.32 0.01 0.01 0.05 0.94 0.18 0.14 0.08 -0.05

Eigenval 7.23 4.72 3.94 2.85 1.56 1.04 5.84 5.07 3.08 2.48 1.94 1.21 1.10 1.02

% total Variance 30.11 19.65 16.41 11.86 6.52 4.33 24.34 21.13 12.83 10.33 8.10 5.03 4.58 4.27

Cumul. Eigenval 7.23 11.94 15.88 18.73 20.29 21.33 5.84 10.91 13.99 16.47 18.41 19.62 20.72 21.75

Cumul. % 30.11 49.76 66.17 78.03 84.55 88.89 24.34 45.46 58.29 68.62 76.72 81.76 86.34 90.61


16/16

a

b

Figure 1 Concentration mean carboxylic acids at two sites during daytime and

nighttime (a) Non-episodic pollution period (b) PM10 episode.

TOT site during Non - episodic pollution period

Carboxylic acids

Acetica

cid

Formic

acid

Glutari

cacid

Succini

cacid

Malica

cid

Maloni

cacid

Tartari

cacid

Maleic

acid

Fumaric

acid

Oxalica

cid

Phthali

cacid

Citrica

cid

Concentration(ngm-3)

0102030405060708090

100110120200

300

400

500

600

700

800

900

1000

Daytime (PM10 mass conc.= 86.03 +/- 34.11 g m-3)Nighttime (PM10 mass conc.= 70.60 +/- 19.41 g m-3)

TOT site during PM10

episode

Carboxylic acids

Acetica

cid

Formic

acid

Glutari

cacid

Succini

cacid

Malica

cid

Maloni

cacid

Tartari

cacid

Maleic

acid

Fumaric

acid

Oxalica

cid

Phthali

cacid

Citrica

cid


0

50

100

150

200

250

300

500

600

700

800

900

1000

1100

1200

1300

Daytime (PM10

mass conc.= 143.39 +/- 16.62g m-3)Nighttime (PM

10mass conc.= 139.02 +/- 19.89g m-3)

CMU site during PM10

episode

Carboxylic acids

Acetica

cid

Formic

acid

Glutari

cacid

Succini

cacid

Malica

cid

Maloni

cacid

Tartari

cacid

Maleic

acid

Fumaric

acid

Oxalica

cid

Phthali

cacid

Citrica

cid


0

100

200

300

400

800

1000

1200

1400Daytime (PM

10mass conc.= 145.27 +/- 17.19g m-3)

Nighttime (PM10

mass conc.= 133.86 +/- 7.88g m-3)

CMU site during Non - episodic pollution period

Carboxylic acids

Acetica

cid

Formic

acid

Glutari

cacid

Succini

cacid

Malica

cid

Malonic

acid

Tartari

cacid

Maleic

acid

Fumaric

acid

Oxalica

cid

Phthali

cacid

Citrica

cid


0

20

40

60

80

100

120

140

160

180

300

400500

600

700

800

900

1000

Daytime (PM10 mass conc.= 56.94 +/- 30.26 g m-3)Nighttime (PM10 mass conc.= 59.35 +/- 33.29 g m-3)

Documents

Kagawa Contents 2012