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Assessing Polycyclic Aromatic Hydrocarbons (PAHs) using passive air sampling in the atmosphere of one of the most wood-smoke-polluted cities in Chile: The case study of Temuco

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1
3Assessing Polycyclic Aromatic Hydrocarbons (PAHs) using passive air
4sampling in the atmosphere of one of the most wood-smoke-polluted
5cities in Chile: The case study of Temuco
6
7
8Karla Pozo
a,b,c,
, Victor H. Estellano
b
, Tom Harner
d
, Luis Diaz-Robles
e,h
, Francisco Cereceda-Balic
f
,
9Pablo Etcharren
g
, Katerine Pozo
h
, Fabian Guerrero
f
, Alberto Vergara-Fernández
i
10
a
RECETOX Research Centre for Toxic Compounds in the Environment, Masaryk University, Kamenice 3/126, 625 00 Brno, Czech Republic
11
b
Department of Physical, Earth and Environmental Sciences, University of Siena, Siena, Italy
12
c
Facultad de Ciencias, Universidad Católica Santísima Concepción, Concepción, Chile
13
d
Air Quality Processes Research Section, Environment Canada, 4905 Dufferin Street, Toronto, Ontario M3H 5T4, Canada
14
e
Departamento de Ingeniería Química, Universidad de Santiago de Chile, Chile
15
f
Environmental Chemistry Laboratory (LQA), Centre for Environmental Technologies (CETAM), Universidad Técnica Federico Santa María, Valparaíso, Chile
16
g
Secretaría Regional Ministerial del Ministerio del Medio Ambiente, Región de La Araucanía, Chile
17
h
Facultad de Recursos Naturales, Universidad Católica de Temuco, Temuco, Chile
18
i
Facultad de Ingeniería y Ciencias Aplicadas, Universidad de los Andes, Chile
19
20
22 highlights
23
24
PAHs were measured in one of the most wood-smoke-polluted cities in the world.
25
PAHs highest levels were detected in winter season in Temuco city.
26
Residential wood combustion (RWC) has a strong influence in PAH levels.
27
Good agreement between PAH profiles in active (PM10) and passive samples was detected.
28
PUF disk is useful for tracking effectiveness of pollution control measures in urban areas.
29
31
article info
32 Article history:
33 Received 3 January 2015
34 Received in revised form 23 April 2015
35 Accepted 25 April 2015
36 Available online xxxx
37 Keywords:
38 Temuco
39 PAHs
40 PUF disk
41 Wood combustion
42 Public health
43
44
abstract
45
This study addresses human health concerns in Temuco that are attributed to wood smoke and related
46
pollutants associated with wood burning activities that are prevalent in the Temuco city. Polycyclic
47
Aromatic Hydrocarbons (PAHs) were measured in air across urban and rural sites over three seasons
48
in Temuco in Chile using polyurethane foam (PUF) disk passive air samplers (PUF-PAS). Concentrations
49
of
R
PAHs (15 congeners) in air ranged from BDL to 70 ng m
3
and were highest during the winter sea-
50
son, which is attributed to emissions from residential heating by wood combustion. The results for all
51
three seasons showed that the PAH plume was widespread across all sites including rural sites on the
52
outskirts of Temuco. Some interesting variations were observed between seasons in the composition of
53
PAHs, which were attributed to differences in seasonal point sources. A comparison of the PAH compo-
54
sition in the passive samples with active samples (gas + particle phase) from the same site revealed sim-
55
ilar congener profiles. Overall, the study demonstrated that the PUF disk passive air sampler provides a
56
simple approach for measuring PAHs in air and for tracking effectiveness of pollution control measures in
57
urban areas in order to improve public health.
58
Ó2015 Published by Elsevier Ltd.
59
60
61
62
1. Introduction
63
Temuco is located in central Chile and is one of the most highly
64
wood-smoke-polluted cities in the country. Epidemiological
65
studies have been conducted in this urban area to establish the link
66
between air quality and health. Sanhueza et al. (2009, 2005)
67
reported a strong relationship between PM10 and daily mortality
68
cases (1997–2002) among subjects over 65 years old. Although,
69
the high levels of PM2.5 and PM10 are clearly causing health prob-
70
lems to the population there is still missing information of the
71
chemical composition of atmospheric pollution in Temuco.
http://dx.doi.org/10.1016/j.chemosphere.2015.04.077
0045-6535/Ó2015 Published by Elsevier Ltd.
Corresponding author at: Facultad de Ciencias, Universidad Católica Santísima
Concepción, Concepción, Chile.
E-mail address: kpozo@ucsc.cl (K. Pozo).
Chemosphere xxx (2015) xxx–xxx
Contents lists available at ScienceDirect
Chemosphere
journal homepage: www.elsevier.com/locate/chemosphere
CHEM 16083 No. of Pages 7, Model 5G
28 April 2015
Please cite this article in press as: Pozo, K., et al. Assessing Polycyclic Aromatic Hydrocarbons (PAHs) using passive air sampling in the atmosphere of one
of the most wood-smoke-polluted cities in Chile: The case study of Temuco. Chemosphere (2015), http://dx.doi.org/10.1016/j.chemosphere.2015.04.077
72
Information on urban air quality is generally lacking across Chile
73
because the conventional air monitoring techniques rely on active
74
air sampling which is costly and requires electrical power and
75
instrument maintenance. In the last decade, the application of pas-
76
sive air samplers (PAS) consisting of polyurethane foam (PUF) disks
77
has contributed significantly to improving knowledge of environ-
78
mental levels and spatial distribution of chemicals around the
79
world (Pozo et al., 2009; Bogdal et al., 2013).
80
Polycyclic Aromatic Hydrocarbons (PAHs) have received consid-
81
erable attention as an important class of atmospheric organic pol-
82
lutants due to the carcinogenic and mutagenic properties of some
83
of these compounds and their derivatives (Keyte et al., 2013). As a
84
result of their carcinogenic activity, many PAHs have been there-
85
fore included in lists of priority pollutants (WHO, 1998). PAHs in
86
the atmosphere can be sorbed onto airborne particulate matter
87
and are emitted from residential wood combustion and vehicle
88
traffic (WHO, 1998). Currently, there is much information on the
89
multi-ringed higher molecular weight PAHs; however, the lower
90
molecular weight vapour-phase PAH components have been rather
91
neglected. Although these lighter compounds have weaker car-
92
cinogenic/mutagenic properties, they are the most abundant in
93
the urban atmosphere and react with other pollutants to form
94
more toxic derivatives (Park et al., 2002). Consequently, the impli-
95
cation for human exposure to mixtures of PAHs rather than to indi-
96
vidual substances is quite important.
97
Chile has not yet established legally enforceable environmental
98
air standards for PAHs. The Chilean regulation has only set the par-
99
ticles air quality index (ICAP in Spanish) for particulate matter
100
(PM
10
and PM
2.5
) and the gases air quality index (ICAG in
101
Spanish) for O
3
and other gases. These indexes are defined to help
102
recognize episodes of atmospheric pollution (Diaz-Robles et al.,
103
2008; Díaz-Robles et al., 2011, 2014). Recently, two actions have
104
been initiated by Chilean regulations: (i) a regional PM10 restric-
105
tion to improve air quality in Temuco city (implemented in
106
2010) and (ii) a national action on the Chilean standard for PM
2.5
107
(implemented January 1, 2012).
108
However, advances in reducing the number of days of PM
10
109
exceedances have not been achieved yet in Temuco. In fact, there
110
has been a gradual increase in PM10 in Temuco in recent years.
111
It is also noteworthy that in 2013, for the entire month of April,
112
the city was designated as a non-attainment area for PM2.5.
113
In 2008, a pilot study was conducted in three different cities of
114
Chile (Santiago, Concepción and Temuco) to assess the spatial and
115
seasonal variation of semivolatile organic compounds (SVOCs)
116
using the PUF disk PAS. In this study we report the results of
117
PAHs in the urban and rural areas of Temuco. We also compare
118
the PAH levels and composition patterns measured by the PUF disk
119
sampler with results from active sampling (PM10) to gain insight
120
into the sampling of gas-phase and particle-phase PAHs by PUF
121
disk samplers. Lastly, principal component analysis (PCA) was
122
applied to investigate correlations between sampling sites, sam-
123
pling period and similarities among sites.
124
2. Material and methods
125
2.1. Study area
126
Temuco is the capital of the Araucanía Region in southern Chile.
127
The city is located 670 km south of Santiago. According to the 2012
128
census by the National Statistics Institute (INE), Gran Temuco had
129
population of 345,240, with 95% of people living in urban areas and
130
the 5% in rural areas. Many crops and fruits, and has an abundance
131
of forests. Detailed information about Temuco is provided in the
132
Supporting Material (SM) (Text S1) (Fig. S1). Air quality has deteri-
133
orated in Temuco due to wood burning, which is the primary
134
source of heat for most of the residents. Further information on
135
Temuco’s morphology and climatology is provided in the (Text S1).
136
2.2. Meteorological conditions
137
Meteorological parameters (e.g. hourly air temperature, relative
138
humidity, wind speed) were obtained from an automated NUS
139
weather station located at ‘‘Las Encinas’’ (LE) station (Fig. S2,
140
Table S1). The LE station is operated under the Environmental
141
Ministry and is located in the center of a vacant lot in a residential
142
area, 2.7 km west of the city center. Active air sampling for PAHs
143
(PM10) was conducted at LE station during the course of this study
144
and results were reported by Cereceda et al. (2012).
145
2.3. Sampling sites
146
Polyurethane foam (PUF) disks were deployed at 6 sites in
147
Temuco including two rural sites (Cerro Ñielol: CNL; Diego
148
Portales: DP) and four urban sites (Padre Las Casas: PLC; Temuco
149
down town: TC; Museo Ferroviario: MF, and Las Encinas: LE)
150
(Fig. 1). Details of each sampling site are given in the SM
151
Table S1. PUF disks were deployed for a full year over three consec-
152
utive sampling periods. The sampling periods were: April 2008 to
153
April 2009 (Period 1: April to July 2008, Period 2: August to
154
November 2008, and Period 3: December 2008 to March 2009).
155
2.4. Sampler preparation and deployment
156
PUF disks were prepared as described previously (Pozo et al.,
157
2009). During exposure, PUF disks (14 cm diameter; 1.35 cm thick;
158
surface area, 365 cm
2
; mass, 4.40 g; volume, 207 cm
3
; density,
159
0.0213 g cm
3
; PacWill Environmental, Stoney Creek, ON), were
160
housed inside a stainless steel chamber. The chamber consisted
161
of two stainless steel domes with external diameters of 30 cm
162
and 20 cm (Fig. S3).
163
Prior to extraction, PUF disks were spiked with a recovery stan-
164
dard consisting of
13
C PCB 105 and d
10
Phenanthrene (99%,
165
Cambridge Isotope Laboratory) and extracted in a Soxhlet for
166
24 h using petroleum ether. Details about the sampling procedure
167
are reported in Pozo et al. (2012), Estellano et al. (2012, 2014).
168
2.5. Chemical analysis
169
The final extracts were analyzed for 15 PAHs using the follow-
170
ing ions: Acenaphthylene (152), Acenaphthene (154), Fluorene
171
(166), Phenanthrene (178), Anthracene (178), Fluoranthene (202),
172
Pyrene (202), Benz(a)anthracene (228), Chrysene (228),
173
Benzo(b)fluoranthene (252), Benzo(k)fluoranthene (252),
174
Benzo(a)pyrene (252), Indeno(1,2,3-c,d)pyrene (276),
175
Dibenzo(a,h)anthracene (278), Benzo(g,h,i)perylene (276), and
176
Retene (219). Analysis of PUF disk extracts for PAHs was carried
177
out by gas chromatography–mass spectrometry (GC–MS) on a
178
GC-Trace™ GC 2000 (equipped with auto sampler AS3000), and
179
MS Polaris Q ionic trap (Thermo Finnigan), using positive electron
180
impact-selected ion monitoring (EI-SIM). The GC works with a cap-
181
illary column ZB-5 ms (30 m 0.25 mm internal 0.25
l
m) from the
182
Phenomenex, USA. A sample of 2
l
L was injected in splitless mode
183
at 250 °C. The oven temperature program was as follows: start at
184
50 °C (hold 2 min), 50–120 °Cat30°Cmin
1
, 120–280 °Cat
185
6°C min
1
(hold 15 min) (Estellano et al., 2012; Pozo et al., 2012).
186
2.6. Quality Assurance/Quality Control (QA/QC)
187
Method recoveries for target PAHs were previously assessed for
188
the analysis laboratory and were generally >70%. Sample-specific
189
surrogate recoveries Method for d
10
Phenanthrene (that was added
2K. Pozo et al. / Chemosphere xxx (2015) xxx–xxx
CHEM 16083 No. of Pages 7, Model 5G
28 April 2015
Please cite this article in press as: Pozo, K., et al. Assessing Polycyclic Aromatic Hydrocarbons (PAHs) using passive air sampling in the atmosphere of one
of the most wood-smoke-polluted cities in Chile: The case study of Temuco. Chemosphere (2015), http://dx.doi.org/10.1016/j.chemosphere.2015.04.077
190
to each sample prior to extraction was 75 ± 10%. Blank levels were
191
assessed for 4 field blanks and 4 laboratory blanks (solvent blanks).
192
Field blanks were below detection for all screened compounds so
193
no blank correction was required.
194
Method detection limits (MDL) in air samples were defined as
195
the average blank (n= 8) plus three standard deviations (SD). The
196
instrumental detection limits were determined by assessing the
197
injection amount that corresponds to a signal-to-noise value of
198
3:1. When target compounds were not detected in blanks, 1/2 of
199
the instrumental detection limit (IDL) was used substituted for
200
the MDL (Table 1).
201
2.7. Statistical analysis
202
Statistical analysis including Principal Component Analysis
203
(PCA) and Pearson correlation were performed using XLSTAT pro-
204
gram. PCA is a multivariate statistical method. In this statistical
205
procedure a new set of variables (principal components) are
206
derived from a linear combination of the original variables or
207
observations through an orthogonal transformation. Prior to per-
208
forming PCA analysis, the data were natural log transformed. The
209
first axis (first principal component) explains the maximum
210
amount of variation within the data set. Subsequent axes (principal
211
components) are derived with the added constraint that they are
212
orthogonal to the previous derived axes. Spatial arrangement of
213
compounds was analyzed to understand relationships among the
214
compounds analyzed, which could provide insight to the potential
215
sources. Varimax rotation was used as the rotation method for PCA
216
analysis (Kaiser, 1958). This rotation is aimed at maximizing the
217
variances of the squared raw factor loadings across variables for
218
each factor; this is equivalent to maximizing the variances in the
219
columns of the matrix of the squared raw factor loadings.
220
3. Results and discussion
221
3.1. Deriving air concentrations
222
The approach for calculating air concentrations from passive
223
sampling data has been presented in detail previously (Shoeib
224
and Harner, 2002; Harner et al., 2013). Briefly, the air concentra-
225
tion for each analyte is estimated by the amount of chemical accu-
226
mulated on the PUF disk (determined through quantitative
227
analysis of the PUF disk extract; ng sampler
1
) divided by the
228
effective air sample volume (V
air
,m
3
) of each specific analyte.
229
The effective air volume (EAV) was calculated using the GAPS
230
Network template (Harner, 2014). This template used the Eq. (1)
30 ng/m
3
*
Period 1
Period 2
Period 3
Fig. 1. Concentrations (ng m
3
) of PAHs in air at the area of Temuco City. Sampling sites: two rural sites (CNL: Cerro n
ˇielol; DP: Diego Portales) and four urban sites (PLC:
Padre las casas; TC: Temuco Centro; MF: Museo Ferroviario and LE: Las Encinas) (
= not available).
K. Pozo et al. / Chemosphere xxx (2015) xxx–xxx 3
CHEM 16083 No. of Pages 7, Model 5G
28 April 2015
Please cite this article in press as: Pozo, K., et al. Assessing Polycyclic Aromatic Hydrocarbons (PAHs) using passive air sampling in the atmosphere of one
of the most wood-smoke-polluted cities in Chile: The case study of Temuco. Chemosphere (2015), http://dx.doi.org/10.1016/j.chemosphere.2015.04.077
231
from Harner et al. (2013). This equation describes the full uptake
232
profile. The uptake profile has two main phases: (a) initially a lin-
233
ear constant uptake phase described by the sampling rate R
234
(m
3
d
1
); Ris governed by the surface area of the sampler and
235
the boundary layer air-side mass transfer coefficient, (b) this is fol-
236
lowed by the plateau or equilibrium phase that may develop for
237
the more volatile compounds as they approach equilibrium in
238
the PUF disk. This phase is described by the PUF-air partition coef-
239
ficient (K
PUF-A
) and related to the octanol–air partition coefficient,
240
K
OA
(Shoeib and Harner, 2002). The estimation of the EAV using
241
the GAPS template requires information on deployment time, aver-
242
age temperature during deployment (since K
PUF-A
varies with tem-
243
perature) and the R-value (see the SM, Table S1). The default value
244
of 4 m
3
d
1
was used which is based on previous calibration stud-
245
ies of the PUF disk sampler for non-polar hydrophobic chemicals
246
including PAHs (Gouin et al., 2005; Klanova et al., 2008; Pozo
247
et al., 2009; He and Balasubramanian, 2010; Harner et al., 2013).
248
For the higher molecular weight PAHs (high K
PUF-A
values), sam-
249
pling remains in the linear phase during the deployment period
250
and the EAV is maximized and essentially equivalent to the Rvalue
251
multiplied by the deployment days. Lower EAV are calculated for
252
the lower molecular weight PAHs (2–3 ring) that approach equilib-
253
rium during the deployment period (Table 1,Table S1).
254
3.2. PAH concentrations in air
255
Table 1 presents the concentrations (ng m
3
) in air of individual
256
and total PAHs at six sites in Temuco city. Concentrations (ng m
3
)
257
of total PAHs (
R
15
) in air ranged from BDL to 70 during the three
258
sampling periods (Fig. 1). However, overall there was not a large
259
difference between PAH concentrations in air between urban sites
260
and rural sites investigated in this study. This indicates that PAH
261
emissions from the city of Temuco influence a large area that
262
includes the outskirts and rural areas around the city. In 2009, a
263
wood utilization survey was conducted in Temuco and showed a
264
similar percentage of wood utilization (5–10%) with exception of
265
PLC (35%) (Fig. S4). The concentrations of PAHs in Temuco are in-
266
line with the highest values of other selected studies in urban
267
and industrial sites where PUF disk PAS were used, including: a
268
survey across Europe by Jaward et al. (2004) with the following
269
highest concentration in air for
R
PAH (ng m
3
) – Moscow-Russia
270
(70), and Middlesborough, UK (40), with an overall range of
271
0.5–70 and a median of 10; a study in Manila, Phillipines by
272
Santiago and Cayetano (2007) reported
R
PAH in the range of
273
50–80; Kaya et al. (2012) also reported levels of PAHs in Turkey
274
(from 2 to 800 ng m
3
) and Wannaz et al. (2013) found
R
PAH
275
in the range of (5–30 ng m
3
) in the city of Cordoba in
276
Argentina. In Chile, Pozo et al. (2012) reported 50 and 230 (ng m
3
)
277
at urban and industrial sites in Concepción, respectively.
278
The highest PAH levels in Temuco were detected during period
279
1 and were about 4 times higher compared to the other periods.
280
The
R
PAH (ng m
3
) was as follows: 40 ± 5 for period 1, 14 ± 1 for
281
period 2, and 10 ± 12 for period 3. Period 1 (April–July) represents
282
the winter season when there is greatest emissions of PAHs, asso-
283
ciated mainly with residential wood combustion (80–95% of air
284
pollutants) (Hellén et al., 2008) and supplemented by other
Table 1
Concentrations (ng m
3
) in air of PAHs in Temuco, Chile during three sampling periods in 2008–2009.
Compounds Acy Ace Flu Phe Ant Flt Pyr BaA Chry BbF BkB BaP I123cdP BghiP DahA Total
PAHs
Period 1 DP 18.6 0.8 0.3 17.1 BDL 5.4 3.9 0.2 0.4 0.1 BDL 0.05 BDL BDL BDL 47
PLC 6.8 1.0 3.1 14.7 1.0 4.1 3.4 0.3 0.4 0.1 BDL 0.02 BDL 0.2 BDL 35
TC 17.5 0.4 0.2 8.9 0.1 2.7 2.6 0.1 0.1 0.04 0.01 0.02 BDL 0.1 BDL 33
MF 36.2 0.8 0.3 21.1 BDL 7.8 6.8 0.2 0.4 0.1 BDL 0.05 BDL 0.2 BDL 74
CNL 4.1 1.0 0.4 10.2 BDL 1.6 1.2 0.0 0.1 0.03 BDL BDL BDL BDL BDL 19
LET 1.7 0.2 0.1 10.5 BDL 6.5 5.3 0.4 0.5 0.1 0.0 0.05 BDL 0.2 BDL 25
Vair, m
3
(86 days,
18 °C)
63 29 34 116 116 291 291 328 328 342 342 342 344 344 344
Period 2 DP 0.6 0.2 0.2 3.4 0.2 1.3 1.0 0.0 0.1 0.0 0.01 0.01 BDL 0.1 BDL 7
PLC 0.3 0.1 0.1 6.1 0.3 7.1 5.8 0.3 0.7 0.1 0.03 0.01 0.01 0.1 BDL 21
TC 0.8 0.9 0.3 8.1 0.0 2.2 3.0 0.1 0.3 0.1 0.02 0.01 0.01 0.2 BDL 16
MF 0.3 0.5 0.1 10.9 0.6 4.3 3.3 0.1 0.3 0.1 0.02 BDL 0.01 0.1 BDL 21
CNL 0.1 0.1 0.0 2.6 0.1 0.6 0.5 0.0 0.0 0.0 0.00 BDL BDL BDL BDL 4
LET 0.4 0.1 0.1 7.4 0.1 2.5 2.0 0.0 0.3 0.0 0.01 BDL 0.01 0.1 BDL 13
Vair, m
3
(117 days,
14 °C)
76 35 41 145 145 393 393 445 445 465 465 465 468 468 468
Period 3 DP 0.8 1.2 0.3 1.2 0.1 0.4 0.2 0.0 0.0 0.0 BDL BDL BDL BDL BDL 4
PLC 0.9 0.6 0.3 7.6 0.9 3.5 3.0 0.3 0.4 0.1 0.03 0.02 0.01 0.1 BDL 18
TC N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A
MF 0.9 0.8 0.3 4.5 0.3 1.7 1.3 0.1 0.2 0.03 0.01 0.01 BDL 0.1 BDL 10
CNL 1.3 2.2 0.4 2.5 BDL 0.5 0.3 0.03 0.04 0.01 BDL BDL BDL BDL BDL 7
LET 1.6 1.2 0.6 6.3 0.4 2.0 1.7 0.1 0.2 0.05 0.01 0.01 0.01 0.1 BDL 14
Vair, m
3
(110 days,
20 °C)
58 27 31 110 110 347 347 410 410 436 436 436 440 440 440
IDL 0.002 0.001 0.002 0.002 0.002 0.004 0.002 0.000 0.000 0.001 0.002 0.0017 0.003 0.002 0.003
MDL 0.001 0.001 0.001 0.001 0.001 0.002 0.001 0.000 0.000 0.001 0.001 0.001 0.001 0.001 0.001
Abbreviations: Ur = Urban, Rural = Ru, BDL = Below detection limit. N/A = Not available. Acenaphthylene (Acy). Acenaphthene (Ace), Fluorene (Flu), Phenanthene (Phe),
Antracene (An), Fluoranthene (Flt), Pyrene (Pyr), Benzo(a)antracene (BaA), Chrysene (Chry), Benzo(b)fluoranthene (BbF), Benzo(k)fluoranthene (BbF), Benzo(a)pyrene (BaP),
Indeno(123 cd)pyrene (IcdP), Benzo(ghi)pyrene (BghiP). Sampling sites: two rural sites (Cerro ñielol: CNL; Diego Portales: DP) and four urban sites (Padre las casas: PLC;
Temuco Centro: TC; Museo Ferroviario: MF and Las Encinas: LE).
a
PPAHs: 13 EPA priority pollutants. Period 1: April to July 2008. Period 2: August to November 2008 and
Period 3: December 2008 to March 2009. Vair (m
3
) derived from Harner et al. (2014).
4K. Pozo et al. / Chemosphere xxx (2015) xxx–xxx
CHEM 16083 No. of Pages 7, Model 5G
28 April 2015
Please cite this article in press as: Pozo, K., et al. Assessing Polycyclic Aromatic Hydrocarbons (PAHs) using passive air sampling in the atmosphere of one
of the most wood-smoke-polluted cities in Chile: The case study of Temuco. Chemosphere (2015), http://dx.doi.org/10.1016/j.chemosphere.2015.04.077
285
industrial and vehicular emissions. This pattern is in line with
286
studies in other areas of the world, for instance by Ravindra et al.
287
(2006) in Flanders-Belgium, in European cities by Prevedouros
288
et al. (2004) and in Higashi Hiroshima, Japan (Tham et al., 2008).
289
In particular, the urban site MF that had the highest levels of
290
PAHs is located close to a malt toasting facility that uses coal as
291
the fuel for its boilers and also in the vicinity of train railway.
292
Details regarding the PAH congener compositions are discussed
293
later. Meteorology also contributes to Temuco’s deteriorating air
294
quality and higher PAH air burdens during the winter. This
295
includes, a low inversion layer, reduced air mass dispersion, and
296
lower rainfall during the winter months (Diaz-Robles et al., 2008).
297
In an effort to improve urban air quality, national authorities
298
have implemented an atmospheric decontamination plan (ADP)
299
for PM10 in 2010 consisting of several measures including, inter
300
alia, prohibiting the use of wet wood, a wood stove change-out
301
program, and educational programs. So far the implementation of
302
this plan has not resulted in documented improvements to air
303
quality at the national scale. In addition, in October 2014 the
304
new Chilean emission control standard (DS39/2012) for wood
305
stoves came into effect, which is more stringent than the US stan-
306
dard. This new standard will only allow for the sale of certified
307
wood stoves in Chile.
308
3.3. PAH fingerprints
309
The composition of the PAHs in air at the Temuco sampling sites
310
was dominated by lower molecular weight PAHs characterized
311
mainly by three-ring (60–90%) and four-ring (10–30%) congeners
312
(Fig. S5). This is consistent with previous studies of PAHs in
313
Temuco (Cereceda-Balic et al., 2012). Based on the average for
314
the six sampling sites over the three periods, the dominant individ-
315
ual PAHs had the following contributions to total PAHs: phenan-
316
threne (35–45%), fluoranthene (11–15%) and pyrene (9–12%).
317
Dominance of phenanthrene is typical for emissions from biomass
318
combustion, particularly wood combustion (Rogge et al., 1998).
319
Cereceda-Balic et al. (2012) also reported a high phenanthrene
320
composition of about 74% for Temuco using active sampling.
321
Interestingly, during period 1 (winter) the PAH composition
322
was enriched in acenaphthylene (acy) (35%) across most of the
323
sites (MF, TC, DP) which is unusual (Fig. S6). This points to a sea-
324
sonal and probably a different source, other than residential wood
325
combustion, of Acy. Acy occurs in coal tar (2%) and is produced
326
industrially by dehydrogenation of Acenaphthene. The main
327
sources of Acy are believed to be vehicle exhaust, coal, coal tar,
328
asphalt, wildfires, agricultural burning and hazardous waste sites
329
(USEPA, 2013).
330
Previous studies have demonstrated that PUF disk samplers
331
capture both lower molecular weight (gas-phase) and high molec-
332
ular weight (particle-phase) PAHs, however some differences have
333
been reported in sampling efficiency for gas-versus particle-phase
334
PAHs (Chaemfa et al., 2008; Klanova et al., 2008; Harner et al.,
335
2013; Bohlin et al., 2014). Even though it contributes in a small
336
way to total PAHs in air, the particle-phase component of PAHs
337
is important as most of the toxic burden of PAHs (carcinogenicity)
338
is associated with the higher molecular weight compounds.
339
In order to assess the ability of the PUF disk sampler to capture
340
particle–phase PAHs, we compare the PAHs fingerprint obtained
341
with PAS-PUF from our study with active sampling (high vol) at
342
Las Encinas (LE) station in Temuco, for samples collected during
343
passive sampling period 2. Active sampling was conducted for
344
24 h over 1 month (once per week) during August 2008. Fig. 2
345
shows good agreement between PAH profiles in active (PM10)
346
(SINCA, 2014) and passive samples (PUF disk) (p< 0.05; r
2
= 0.98)
347
for both low and high molecular weight PAHs (Fig. 3). This suggests
348
that the PUF disk samplers are capturing both gas-phase and par-
349
ticle-phase PAHs with minimal bias, relative to how these phases
350
are sampled by the active sampler. This is consistent with the
351
recent findings of Harner et al. (2013).
352
The topic of particle-phase sampling by passive PUF disk sam-
353
plers is a matter of ongoing research and we note that different
354
designs of active samplers may capture different particle-phase
355
fractions. Also, some variability between passive and active sam-
356
plers is expected based on sampling period differences – i.e. in
357
the current study the active sampler represents only 7% of the time
358
that the passives were collected. Consequently, the collected PAH
359
burdens and profiles will exhibit some variability depending on
360
the temporal nature of PAH emissions, and on meteorological fac-
361
tors such as wind direction. The temporal variability of PAH emis-
362
sions and concentrations in air at the LE sampling site may also
363
explain the higher total PAH concentrations reported by Cereceda
364
et al. (2012) using active sampling, compared to the current study.
365
3.4. Principal component analysis (PCA) analysis
366
PCA is a useful data analysis technique for examining various
367
factors in an attempt to reveal relationships and patterns within
368
data sets. Fig. 4, shows the score plot for PCA of the PAHs concen-
369
trations in air in Temuco during the three sampling periods. In
370
total, four PCA plots were generated. The PCA analysis allows us
371
to evaluate the PAH ‘fingerprints’ for the three sampling periods
372
individually. Based on the loading of the factors we observed that,
373
in general, the first and second components explain more than
Fig. 2. Comparison of PAH composition in air at Las Encinas (LE) determined using
passive (PUF disk) and intermittent active samplers (high vol, gas + particle phase,
PM2.5). Active sampling results were reported previously in Cereceda et al. (2012).
Note: the offset in reported concentrations in air for PAHs can be due to differences
in sampling times between active and passive samplers and/or to offsets between
laboratories where samples from the two studies were analyzed.
Fig. 3. PAHs concentrations in air for individual PAH compounds using active air
sampling (PM10) (SINCA, 2014) and passive sampling (PUF disk) at LE station
during period 2.
K. Pozo et al. / Chemosphere xxx (2015) xxx–xxx 5
CHEM 16083 No. of Pages 7, Model 5G
28 April 2015
Please cite this article in press as: Pozo, K., et al. Assessing Polycyclic Aromatic Hydrocarbons (PAHs) using passive air sampling in the atmosphere of one
of the most wood-smoke-polluted cities in Chile: The case study of Temuco. Chemosphere (2015), http://dx.doi.org/10.1016/j.chemosphere.2015.04.077
374
95% of the variance and indicate positive statistical correlation
375
(r= 0.8; p> 0.05) between variables with a high loading for Phe
376
during all three sampling periods. We also observe that Acy
377
(during period 1) was grouped separately in Fig. 3a indicating a
378
different and unknown source during winter season. The PCA
379
analysis also allows us to compare the PAH pattern between
380
the three sampling seasons when plotted together (Fig. 3d). In
381
general during the three sampling period there is a prevalence
382
of Phe (Fig. 3d). The PAHs fingerprint was different among sites
383
during period 3 (summer) as shown in Fig. 3c where the rural
384
sites CNL and DP are grouped separately. This result might reflect
385
differences in the types of emissions that impact these sites
386
during the summer season.
387
4. Conclusions
388
This study is the first to employ passive air samplers in Temuco
389
Chile to assess the spatial extent of pollution associated with PAH
390
emissions. The study reveals that PAH composition varies consid-
391
erably for the different seasons and with highest levels observed
392
in the colder winter months, while they decrease significantly in
393
the warmer months of the year. The highest PAH levels are associ-
394
ated with emissions from residential wood combustion (RWC) for
395
heating with exception of Acy (during period 1) which might be
396
influenced by different sources in the close vicinity of the study
397
area.
398
The study also revealed that PAHs emissions from Temuco have
399
a large area of impact that includes rural areas on the outskirts of
400
the city.
401
Passive air samplers are a cost-effective and simple way to con-
402
duct chemical characterization studies and for tracking the effec-
403
tiveness of efforts that are being implemented at regional and
404
national levels to reduce emissions of PAHs with the aim of
405
improving public health. Further research is still needed in order
406
to implement long term monitoring programs of SVOCs in the
407
country.
408
5. Uncited references
409
Paiva and Sandoval (2009), Pozo et al. (2004) and Sanhueza
410
et al. (2005).
411
Acknowledgments
412
Funding was provided by FONDECYT Project N°1130329 (Karla
413
Pozo) and Fondecyt 1120791 (Luis Diaz-Roblez). We also grateful
414
for logistical support provided by the environmental ministry in
415
Cautin region. This work was carried out with the partial support
416
of core facilities of Research Centre for Toxic Compounds in the
417
Environment (RECETOX) – National Infrastructure for Research of
418
Toxic Compounds in the Environment, project number
419
LM2011028, funded by the Ministry of Education, Youth and
420
Sports of the Czech Republic under the activity, ‘‘Projects of major
421
infrastructures for research, development and innovations’’ and to
422
National Program of Sustainability from the same Ministry
423
(project number is: LO1214). Dr. Fabian Guerreo also thanks the
424
Conicyt-PAI grant for the National competition for PhD thesis
425
2014-78141103.
426
Appendix A. Supplementary material
427
Supplementary data associated with this article can be found, in
428
the online version, at http://dx.doi.org/10.1016/j.chemosphere.
429
2015.04.077.
Acy
Ace
Flu
Phe
Ant
Flt
Pyr
BaA
ChrBbF
BkBBaP
CNL
DP
MF
PLC
TC
LE
-1.5
-1
-0.5
0
0.5
1
1.5
-1.5 -1 -0.5 0 0.5 1 1.5
F2 (45.76 %)
F1 (51.44 %)
Period 1
(F1 and F2: 97.21 %)
Ace
Acy
Flu
Phe
Ant
Flt
Pyr
BaA Chry
BbF
BkB
BaP
I123cdP
CNL
DP
MF
PLC
TC
LE
-1.5
-1
-0.5
0
0.5
1
1.5
-1.5 -1 -0.5 0 0.5 1 1.5
F2 (30.73 %)
F1 (68.68 %)
Period 2
(F1 and F2: 99.41 %)
Ace
Acy
Flu
Phe
Ant Flt
Pyr
BaA Chry
BbF
BkB
BaP
I123cdP
CNL
DP
MF
PLC
LE
-1.5
-1
-0.5
0
0.5
1
1.5
-1.5 -1 -0.5 0 0.5 1 1.5
F2 (44.51 %)
F1 (55.07 %)
Period 3
(F1 and F2: 99.59 %)
Acy
Ace
Flu
Phe
Ant
Flt
Pyr
BaA
Chry
BbF
BkB
BaP
I123cdP
Period 1
Period 2
Period 3
-1.5
-1
-0.5
0
0.5
1
1.5
-1.5 -1 -0.5 0 0.5 1 1.5
F2 (39.89 %)
F1 (58.87 %)
Period 1 , 2, 3
(F1 and F2: 98.75 %)
(a) (b)
(c) (d)
Fig. 4. Score plot for principal component analysis (PCA) applied to concentrations of PAHs (13 congeners detected) in air at Temuco during 2008–2009 sampling using PUF
disk PAS. Period 1, (b) Period 2, (c) Period 3) and (d) Period 1, 2 and 3. Sampling sites: two rural (CNL: Cerro ñielol and DP: Diego Portales) and four urban sites (PLC: Padre las
casas; TC: Temuco Centro; MF: Museo Ferroviario and LE: Las Encinas).
6K. Pozo et al. / Chemosphere xxx (2015) xxx–xxx
CHEM 16083 No. of Pages 7, Model 5G
28 April 2015
Please cite this article in press as: Pozo, K., et al. Assessing Polycyclic Aromatic Hydrocarbons (PAHs) using passive air sampling in the atmosphere of one
of the most wood-smoke-polluted cities in Chile: The case study of Temuco. Chemosphere (2015), http://dx.doi.org/10.1016/j.chemosphere.2015.04.077
430
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K. Pozo et al. / Chemosphere xxx (2015) xxx–xxx 7
CHEM 16083 No. of Pages 7, Model 5G
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Please cite this article in press as: Pozo, K., et al. Assessing Polycyclic Aromatic Hydrocarbons (PAHs) using passive air sampling in the atmosphere of one
of the most wood-smoke-polluted cities in Chile: The case study of Temuco. Chemosphere (2015), http://dx.doi.org/10.1016/j.chemosphere.2015.04.077
... Phenanthrene, Pyrene, and Fluoranthene have been reported to be the most abundant PAHs in outdoor air (Boström et al., 2002). Coincidentally, PAHs produced by the contamination of firewood in Temuco, Chile, are made up mainly of Phenanthrene (35-45%), Fluoranthene (11-15%), and Pyrene (9-12%) (Pozo et al., 2015). ...
... To evaluate PAH's effect, 3 PAH found in the polluted air of Temuco (Pozo et al., 2015) were diluted in DMSO in a 3:1:1 ratio [Phenanthrene (P11409), Fluoranthene (F807) and Pyrene (18551), Sigma Aldrich]. Subsequently, cells were subjected to the effect of PAHs in ascending concentrations from 10 μM to 200 μM for 24h. ...
... PAHs, one of the components in PM 2.5, has caught the attention of scientists as they are an important organic component in particulate matter having mutagenic and carcinogenic properties. Interestingly, Pozo et al. (2015) found that PAHs produced by the contamination of firewood in Temuco, are mainly made up of 3-5 Phenanthrene rings (35-45%), Fluorantrene (11-15%), and Pyrene (9-12%) (Pozo et al., 2015). The inhalation of these organic molecules could explain the high number of patients admitted for acute coronary syndromes at the Dr. Hernán Henríquez Aravena regional hospital (Sanhueza et al., 2009). ...
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... Residential wood combustion (RWC) is an important source of atmospheric pollution worldwide, with ample evidence of its consequences in countries such as Portugal [1], Italy [2], Denmark [3], Finland [4], and Chile [5] among others. This is usually attributed to the pollutants released with the smoke of wood combustion that is composed of a complex mixture of gases (CO, CO 2 , NO X , SO 2 , among others) and particles (PM 10 , PM 2.5 and PM 1.0 ) [6][7][8][9][10], as it also contains several toxic contaminants that include organic compounds such as benzene, formaldehyde and polycyclic aromatic hydrocarbons (PAH) which pose a serious threat to human health [11][12][13][14][15][16]. Moreover, Wang et al. [17] have highlighted the increased health risks associated to indoor ultrafine particle emissions (PM 0.1-2.5 ), which have been found to be neglected in the evaluation of newer combustion technologies, and are linked to higher health risks to the exposed population, while Du et al. [18] observed that the toxicity of the released PAHs from indoor biomass burning (both on cooking and heating stoves) was closely linked to the nature of the burned biomass. ...
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