trends in the elemental composition of pm2.5 in santiago, chile from 1998 to 2006
DESCRIPTION
TRENDS IN THE ELEMENTAL COMPOSITION OF PM2.5 IN SANTIAGO, CHILE FROM 1998 TO 2006 Pablo A. Ruiz Rudolph* , † , Pedro Oyola † , Ernesto Gramsch ‡ , Francisco Moreno ‡ and Petros Koutrakis* - PowerPoint PPT PresentationTRANSCRIPT
TRENDS IN THE ELEMENTAL COMPOSITION OF PM2.5IN SANTIAGO, CHILE FROM 1998 TO 2006
Pablo A. Ruiz Rudolph*,†, Pedro Oyola†, Ernesto Gramsch‡, Francisco Moreno‡ and Petros Koutrakis* * Harvard School of Public Health, Department of Environmental Health, Boston, MA; † Centro Mario Molina Chile, Santiago, Chile
‡University of Santiago, Department of Physics, Santiago, Chile
AIR POLLUTION IN SANTIAGO
SAMPLING
STATISTICAL METHODS•PM2.5 and elements were regressed against meteorological and temporal variables using linear regression models
•Meteorological data were dichotomized or trichotomized as follows:
•Wind speed (ws), ws < 0.8 m/s, 0.8 ≥ ws < 1.6 m/s, ws ≥ 1.6 m
•Relative humidity, rh < 70% and rh ≥ 70%
•Temperature t < 20oC and t ≥ 20oC
•Years were counted from April of one year to March of the following year
•Model
•Where, α is the regression intercept and βyj, βmj, βwj, βwsj, βtmpj, and βrhj are the regression coefficients of the independent variables year (1 to 8), month (1 to 12), weekday (1 to 7), wind speed (1 to 3), temperature (1 to 2) and relative humidity (1 to 2)
•As exponential terms:
[PM] = I * fyearj * fmonthj * fweekdayj * fwsj * ftmpj * frhj
•Fij are the Concentration Impact Factor (CIF). CIFs are multiplicative rather than additive. I.e. a CIF of 2 for June means concentrations in January are twice the concentrations in December
•The CIF for the intercept, I = eα, corresponds to the average concentration at the reference level (e.g. Year 2006, December, Saturday, ws ≥ 1.6 m/s, rh ≥ 70% and tmp ≥ 20 oC)
Acknowledgement
This work was funded by CONAMA RMThe authors want to thank SESMA for sample collection
YEAR EFFECT
MONTH EFFECT
DAY OF WEEK EFFECT
TEMPERATURE EFFECT
HUMIDITY EFFECT
WIND SPEED EFFECT
•Chile does not have PM2.5 standards
•EPA National YEAR Standard is 15 μgr m-3
•EPA National DAILY standard is 35 μgr m-3
•Average concentration was 37.4 μgr m-3
•2.5 times EPA YEAR standard
•EPA daily standard exceeded 40% of the days
PM2.5 Averages•Santiago, Chile has a population of about 6 million people, concentrating 40% of the population of Chile.
•The city is located in a valley (520 above sea level), surrounded by the Andes range to the East and the Coastal range to the West
• Summers are hot and dry, while winters tend to be colder and more humid, with frequent thermal inversions.
•Major sources include large number of industries and a large vehicle and bus fleet (800,000)
•Recent air quality interventions include:
•Street cleaning and tree planting campaign in 1998
•Reduction of lead in gasoline and sulfur in diesel fuels in 2001
•The objective of this work is:
•To asses the effectiveness of these and other measures
•To assess the effect of meteorological and time factors on air pollution levels
•PM2.5 sampling was conducted at the Parque O’Higgins air quality monitoring station
•Twenty-four hour particle samples (midnight to midnight) were collected from April 1998 through March 2006
• Fine particle (PM2.5, aerodynamic diameter <2.5 μm) filter samples were collected on Teflon filters using dichotomous samplers
•Mass was determined by gravimetry and elements by X-ray fluorescence (Desert Research Institute, Reno, NV, USA)
•For each month, only 6 to 8 filters were selected, or about 1 sample every fourth day, for a total of 717 filters analyzed across the eight years of the study
•Only elements that had at least 80% of all reported values above LOD were included in the statistical analysis
• Additionally, meteorological variables were measured at the sampling site and the La Paz air quality monitoring station, located a few kilometers north/northwest.
rhjrhjtmpjtmpjwsjwsjwjwjmjmjyjyjaPM ******]ln[
]var*exp[ ijijfij
0.00
0.25
0.50
0.75
1.00
1.25
1.50
1.75
2.00
MP2.5 Na Al Si S K Ca
Element by year (1998/1999 - 2005/2006)
CIF
1998/1999
1999/2000
2000/2001
2001/2002
2002/2003
2003/2004
2004/2005
2005/2006
0.00
0.25
0.50
0.75
1.00
1.25
1.50
1.75
2.00
Cr Mn Fe Cu Zn Se
Element by year (1998/1999 - 2005/2006)
CIF
1998/1999
1999/2000
2000/2001
2001/2002
2002/2003
2003/2004
2004/2005
2005/2006
0
2
4
6
8
10
12
14
Cl Ni Br Pb
Elements by year (1998/1999 - 2005/2006)
CIF
1998/1999
1999/2000
2000/2001
2001/2002
2002/2003
2003/2004
2004/2005
2005/2006
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
Sunday
Monday
Tuesday
Wednesday
Thurs
day
Fri
day
Satu
rday
Day of week
CIF
Mass
Na
Al
Si
S
Cl
K
Ca
Fe
Se
Br
Pb
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
Su
nd
ay
Mo
nd
ay
Tu
esd
ay
We
dn
esd
ay
Th
urs
da
y
Fri
da
y
Sa
turd
ay
Day of week
CIF
Cr
Mn
Ni
Cu
ZnSUMMARY
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
Janu
ary
Feb
ruar
y
Mar
ch
Apr
il
May
June
July
Aug
ust
Sep
tem
ber
Oct
ober
Nov
embe
r
Dec
embe
r
Month
CIF
Mass
Cl
Cr
Mn
Ni
Cu
Zn
Br
Pb
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
Janu
ary
Feb
ruar
y
Mar
ch
Apr
il
May
June
July
Aug
ust
Sep
tem
ber
Oct
ober
Nov
embe
r
Dec
embe
r
Month
CIF
Na
Al
Si
S
K
Ca
Fe
Se
0.0
0.5
1.0
1.5
Mass Na Al Si S Cl K Ca
Element
CIF
To<20 C To>= 20 C
0.0
0.5
1.0
1.5
Cr Mn Fe Ni Cu Zn Se Br Pb
Element
CIF
0.00.51.01.52.02.53.0
Cr Mn Fe Ni Cu Zn Se Br Pb
Element
Ye
arl
y C
IF
About the authorPablo Ruiz is a Research Fellow at HSPH
and a Research Associate at Centro Mario Molina ChileContact at email [email protected]
0.00.51.01.52.02.53.0
Mass Na Al Si S Cl K Ca
Element
Yea
rly
CIF ws<0.8 ws>= 0.8 and ws<1.6 ws>=1.6
0.0
0.5
1.0
1.5
Mass Na Al Si S Cl K Ca
Element
CIF
RH<70 % RH>= 70%
0.0
0.5
1.0
1.5
Cr Mn Fe Ni Cu Zn Se Br Pb
Element
CIF
Effect
Elements Weekday Month WS To RH
MP2.5, Pb, Br, Cl N Y Y Y N
S, Se, Na N N N N Y
Al, Si, K, Ca,Fe N N Y Y Y
Cr,Mn, Zn Y Y Y Y Y
Ni, Cu Y Y Y N N