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Today, Chile (16 million people) is one of South America's most stable and prosperous nations.1 It leads Latin America in human development, competitiveness, income per capita, globalization, economic freedom, low perception of corruption and state of peace.2 It also ranks high regionally in freedom of the press and democratic development. Its economy is recovering fast from the last global economy recession, growing by 5.2% in 2010. The Monthly Economic Activity Grow Index of March 2011 was 15.2% compared with March 2010, the highest value since 1992.3 In May 2010, Chile became the first South American country to join the Organization for Economic Co-operation and Development, (OECD). However, Chile has serious air quality problems, mainly aerosols.
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28 em august 2011
Copyright 2011 Air & Waste Management Association
28 em august 2011
em • feature
by Luis Díaz-Robles,
Herman Saavedra,
Luis Schiappacasse,
and F. Cereceda-Balic
Luis Díaz-Robles,
Herman Saavedra, and
Luis Schiappacasse are
with the Air Quality Unit
at the Catholic University
of Temuco in Chile.
F. Cereceda-Balic is with
Environmental Technology
Center (CETAM in Spanish)
at the Universidad Técnica
Federico Santa María in
Chile. E-mail:
Today, with a population of 16 million, Chile is one of South America’s most
stable and prosperous nations.1It leads Latin America in human development,
competitiveness, income per capita, globalization, economic freedom, low per-
ception of corruption, and state of peace.2It also ranks high regionally in terms
of freedom of the press and democratic development. Its economy is recovering
fast from the last global economy recession, growing by 5.2% in 2010. The
Monthly Economic Activity Grow Index for March 2011 was 15.2%, the highest
value since 1992.3In May 2010, Chile became the first South American country
to join the Organization for Economic Co-operation and Development (OECD).
However, Chile has serious air quality problems.
The Air Quality in Chile:
Cerro Alegre Hill,
Valparaiso, Chile. august 2011 em 29august 2011 em 29
Geography and Climate
Chile occupies a long, narrow coastal strip between
the Andes Mountains to the east and the Pacific
Ocean to the west, with small mountains in the
center of the country, called the Coast Mountains.
Its climate varies, ranging from the world’s driest
desert in the north, through a Mediterranean-like
climate in the central region, to a rainy climate in
the south. The northern desert contains great mineral
wealth. The relatively small central region dominates
in terms of population and agricultural resources,
where the main cities are located between the
Andes and the Coast Mountains. Southern Chile
is rich in forests and grazing lands and features a
string of volcanoes and lakes.
Weather patterns of the majority of cities in Chile
located in the central depression are detrimental to
the pollutants removal from airshed, especially
during fall and winter. The presence of the Pacific
subtropical anticyclone marks for much of the year
the emergence of the phenomenon of temperature
inversion and a heavy coastal fog (called “vaguada
costera” in Spanish). This favors the generation of
a very stable layer of air near the surface, which
inhibits turbulence and vertical air movement in
these basins.
During the summer, surface heating allows the ero-
sion of the inversion layer on the airshed, resulting
in a significant improvement in ventilation. However,
emissions of nitrogen oxides (NOx) and volatile
organic compounds (VOCs) mainly from mobile
sources, as well as the solar radiation, favor the
formation of ozone in the cities of Santiago and
Rancagua in central Chile. This article presents an
overview of the Chilean air quality standards and
the regions that are in exceedance of the air quality
standards, as well as a broad picture of the air quality
trends in Chile based on available monitoring data.
9 ppm (10 mg/m3)
26 ppm (30 mg/m3)
0.5 μg/m3 b
53 ppb c
213 ppb
150 μg/m3
50 μg/m3
50 μg/m3
20 μg/m3
0.061 ppm
0.031 ppm
0.096 ppm
Averaging Time
8-hr a
1-hr a
Annual (arithmetic average)
Annual (arithmetic average)
1-hr d
24-hr e
Annual f(arithmetic average)
24-hr e
Annual f(arithmetic average)
8-hr g
Annual h(arithmetic average)
24-hr i
0.031 ppm North Zone
0.023 ppm South Zone
0.140 ppm North Zone
0.099 ppm South Zone
0.382 ppm North Zone
0.268 ppm South Zone
Averaging Time
Annual h(arithmetic average)
24-hr j
1-hr k
Primary Standards
Table 1. Chilean National Ambient Air Quality Standards.
Secondary Standards
Notes: aThe three-year average of the 99th percentile of the daily maximum 8-hr or 1-hr concentration must not exceed 9 parts per million (ppm) or 1 ppm, respectively. bThe
two-year average concentration must not exceed 0.5 μg/m3. cThe three-year average concentration must not exceed 53 parts per billion (ppb). dThe three-year average of the
99th percentile of the daily maximum 1-hr average must not exceed 213 ppb. eNot to be exceeded more than seven times per year. fThe three-year average of the weighted
annual mean concentration must not exceed the standard. gThe three-year average of the 99th percentile of the daily maximum 8-hr average must not exceed 61 ppb. hThe
three-year average of the weighted annual mean concentration must not exceed the respective standard. iThe three-year average of the 99th percentile of the 24-hr concentrations
must not exceed 96 ppb. jThe three-year average of the 99.7th percentile of the 24-hr concentrations must not exceed the respective level. kThe three-year average of the
99.73th percentile of the 1-hr concentrations must not exceed the respective level.
Map of Chile.
20 Years of Challenge
Copyright 2011 Air & Waste Management Association
30 em august 2011
Northern Chile
Central Chile
Metropolitan Region
of Santiago
Bernardo O’Higgins
Bernardo O’Higgins
Southern Chile
Tocopilla City
Surrounding zone of CODELCO’s
Chuquicamata Foundry
Surrounding zone of CODELCO’s Potrerillos
Foundry, Salvador Division
Surrounding zone of Hernán Videla Lira
Foundry, Tierra Amarilla and Copiapó cities
Andacollo city
Vantanas Industiral Complex of Puchuncaví
and Quintero cities
Santiago Metropolitan area
Surrounding zone of Caletones Founfry, el
CODELCO’s el Teniente Division, Mostazal,
Codegua, Machalí, and Requínoa cities
Rancagua city
Talca city
Concepción Metropolitan area
Temuco City and Padre Las Casas
Saturated Zone, 2007
Saturated Zone, 1991
Saturated Zone, 1997
Saturated Zone, 1993
Saturated Zone, 2009
Saturated Zone, 1993
Saturated Zone
Latent Zone
Saturated Zone, 1994
Saturated Zone, 2009
Saturated Zone, 2010
Latent Zone, 2007
Saturated Zone, 2005
PM10, SO2
PM10, SO2
PM10, SO2
PM10, O3,
PM10, SO2
Plan/Year a
ADP in elaboration
ADP, 1993, 2001
ADP, 1999
ADP, 1995
ADP in elaboration
ADP, 1993
ADPP b, 1996, 2004,
ADP in elaboration
ADP in elaboration
ADP in elaboration
APP in process
ADP, 2010
Table 2. Chilean zones with severe air quality problems.
30 em august 2011
Chilean Standards
The Chilean Air Quality Standards have been
defined (and have not changed) since 1994, due to
the creation of CONAMA (the Chilean equivalent
of the U.S Environmental Protection Agency) the
same year, and set both primary and secondary
concentration limits for air pollutants. The primary
standards are designed to protect the human
health, while the secondary standards are designed
to protect the ecosystems (see Table 1).
Similar to the United States, areas that are in
exceedance of the standards are designated as
non-attainment areas. The designation of a non-
attainment area contains the precise geographic
area it spans. But there are some differences
between the United States and Chile. In Chile, an
area is designated as a “latent” non-attainment
area, when the pollutant concentrations are
between 80 and 100% of the standard, and as a
“saturated” non-attainment area, when the pollu-
tant concentration exceeds the set standard. These
designations of latent or saturated area form the
basis of the atmospheric prevention plans (APP)
or atmospheric decontamination plans (ADP),
respectively. These plans are similar in scope to the
U.S. State Implementation Plans (SIPs).
Latent and Saturated Areas in Chile
The atmospheric contamination problem was, for
many years, almost exclusively limited to Santiago;
however, many mining zones and other northern,
central, and southern cities in Chile have begun to
Notes: aYear enacted and subsequent revision years; bADPP = Atmospheric Decontamination and Prevention Plan.
Figure 1. Annual minimum,
maximum, and mean aver-
age SO2concentrations
based on 12 sites in the
northern and central regions
of Chile, 1993 to 2009.
Copyright 2011 Air & Waste Management Association august 2011 em 31
Copyright 2011 Air & Waste Management Association
show air quality problems, with severe health con-
sequences for the population. Table 2 shows that
the atmospheric contamination problem in the
main non-attainment regions in Chilean urban and
mining northern zones is largely due to the high
levels of sulfur dioxide (SO2) and particulate matter
(PM10) from copper foundries and coal-burning
power plants; in the central zone, the concerns are
due to PM10, ozone (O3), and SO2coming from
mobile and point sources; while in Chilean southern
urban zones, the main pollutant is PM10 produced
by residential wood combustion (RWC). Besides
these zones that have been declared as saturated
or latent, there are some cities in southern Chile
(e.g., Chillán, Coyhaique, Talca, Valdivia, and Osorno),
where PM10 monitoring studies and campaigns
have started showing alarming air quality results,
compared with those from Temuco city.4These
non-attainment zones cover approximately 40,000
km2, where approximately 6,800,000 inhabitants
are exposed to air pollution.
Air Quality Trends
The specific geographical and meteorological con-
ditions of Chile, plus the anthropogenic emissions
have resulted in high atmospheric levels of PM10,
PM2.5, O3and SO2, and remain a severe problem
since the 1990s. As a result, communities exposed
to high concentrations of these pollutants have
been associated with a rise in mortality and mor-
bidity.5-29 Fortunately, in some industrial centers and
cities, pollution levels have drastically decreased by
the measures established in Chilean regulations.
For example, the annual SO2concentrations in the
copper mining areas of the north and central
regions of Chile decreased substantially (by 77%)
from 1993 to 2009 (see Figure 1). However, the
concentrations of SO2have remained flat or in-
creased from 2004 to 2009 due to the construc-
tion of more coal power plants as a result of the
expansion of the copper industry and its demand
for energy.
Figure 2 shows the evolution of air quality in San-
tiago, from 1989 to 2009, where annual average
concentrations of PM10 and PM2.5 decreased by
33% and 54%, respectively. The percentage of
PM10 reduction was less than PM2.5 because the
coarse fraction emitted by non-point sources (like
RWC) has experienced an increase of 11%. The
O3is still high with a maximum of 93 parts per
billion by volume (ppbv) 8-hr moving average of
2009 in Santiago.30
In some southern urban zones, the control meas-
ures have not been as successful as in Santiago,
because the sources are different and the ADP
began only in 2010. Temuco, for example, has
serious PM problems due to RWC. Since 2002,
this city has experienced degrading air quality (see
Figure 2), with PM10 concentrations increasing
each year, and exceeding the annual and daily
standards systematically, becoming worse each
year.31 Temuco’s ADP and the National Strategy to
control de RWC smoke were implemented in
2010 to help solve this problem.
Past Research Focus
and Future Needs
Since 1991, the air quality research in Chile has
focused initially on data analysis,32-34 and health
effects for short-term exposure.21, 26-29 Subsequently,
Figure 2. Annual average
concentrations of PM10 and
PM2.5 (in µg/m3) in Santi-
ago, Chile, 1989-2009.
Figure 3. Air quality in
Temuco (a) PM10 annual
average and (b) 98 per-
centile and maximum of
Source: Chilean Environmental
32 em august 2011
Copyright 2011 Air & Waste Management Association
areas to further protect human health. While most
of the studies in Chile have focused on PM10,
further analysis should be done for PM2.5 and
ultrafine particles, mainly chemical characterization,
aerosols formation, better air pollution control tech-
nologies, and air quality and local climate change
Chile recently released a new PM2.5 standard,
which will take effect on January 1, 2012. As we
look forward into the future, the importance of
research cannot be neglected. There is a dire need
for detailed ambient and source characterization
through improved monitoring and modeling
efforts thereby helping to meet the challenge. em
it has expanded to important research topics in
establishing and improving forecasting models,31, 35-40
emission inventories and air quality photochemical
modeling,41-51 receptor models,52-55 increased studies
in health effects for cardio-respiratory diseases pro-
duced by PM and carbon monoxide exposure in
Santiago, Temuco, Talcahuano, and Hualpén,5-15
policy-making studies,34, 56-61 indoor air quality,56
and chemical description and monitoring net-
works.32-33, 46, 62-74
While past research has contributed to our under-
standing, it is obvious that more research is needed
to develop better understanding of the sources and
their characteristics to aid in better pollution control.
Owing to the geographical challenges of reducing
air pollution in Chile, better air quality manage-
ment tools are needed in the urban and industrial
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... Chile faces notoriously bad air quality with over 8 million inhabitants exposed to air pollutants above statutory limits between 2015 and 2017 (Lizama & Figueroa Serrano, 2018). Air pollution is largely attributed to woodsmoke, vehicle exhaust, industry and, in some places, coal power plants, magnified by topographical and meteorological conditions (Díaz-Robles et al., 2011). Certain areas with highly concentrated air pollution from coal plants and industry are deemed "sacrifice zones" and inhabitants face elevated risks of cancer and lead poisoning linked to chemicals found in coal ash deposits (Tapia-Gatica et al., 2020). ...
... In most cities in Chile, there are air quality problems related to the presence of high levels of PM 10 and PM 2.5 (particulate matter with an aerodynamic diameter under 2.5 μm) (Díaz-Robles et al., 2011;MMA, 2013). The annual average concentration for PM 10 and PM 2.5 exceeds the guidelines established by the WHO for PM 10 and PM 2.5 , as well as the air quality national standard of Chile, in several cities in Chile (see Fig. 1). ...
A critical analysis of Chile's National Air Quality Information System (NAQIS) is presented, focusing on particulate matter (PM) measurement. This paper examines the complexity, availability and reliability of monitoring station information, the implementation of control systems, the quality assurance protocols of the monitoring station data and the reliability of the measurement systems in areas highly polluted by particulate matter. From information available on the NAQIS website, it is possible to confirm that the PM 2.5 (PM 10) data available on the site correspond to 30.8% (69.2%) of the total information available from the monitoring stations. There is a lack of information regarding the measurement systems used to quantify air pollutants, most of the available data registers contain gaps, almost all of the information is categorized as "preliminary information" and neither standard operating procedures (operational and validation) nor assurance audits or quality control of the measurements are reported. In contrast, events that cause saturation of the monitoring detectors located in northern and southern Chile have been observed using beta attenuation monitoring. In these cases, it can only be concluded that the PM content is equal to or greater than the saturation concentration registered by the monitors and that the air quality indexes obtained from these measurements are underestimated. This occurrence has been observed in 12 (20) public and private stations where PM 2.5 (PM 10) is measured. The shortcomings of the NAQIS data have important repercussions for the conclusions obtained from the data and for how the data are used. However, these issues represent opportunities for improving the system to widen its use, incorporate comparison protocols between equipment, install new stations and standardize the control system and quality assurance.
... However, the main cities in Chile are currently far from lying beneath an azure sky. Chilean cities such as Santiago, Rancagua, Gran Concepción, Temuco, Chillan, Los Ángeles, Osorno, and Coyhaique have deteriorating air quality (Díaz- Robles et al. 2011;MMA 2012MMA , 2013MMA , 2014. This deterioration has mainly been due to an increase in emissions from rapid urban expansion (86.6% Chile's population lives in urban areas) (INE 2016a), biomass burning (high firewood use, mainly in southern cities), an increase in the size and number of vehicles, and industrial activity (Pino et al. 2015;Schueftan et al. 2016). ...
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This study analyzed air quality in terms of the concentrations of sub-10 µm and sub-2.5 µm particulate matter (PM10 and PM2.5, respectively) recorded at 23 automated public monitoring stations located in 16 cities in south-central Chile (Rancagua, Rengo, San Fernando, Curicó, Talca, Maule, Chillán and Chillán Viejo, Gran Concepción, Coronel, Los Ángeles, Temuco and Padre Las Casas, Valdivia, Osorno, Puerto Montt, Coyhaique and Punta Arenas). In each city, the spatial and temporal distributions of the PM10 and PM2.5 concentrations were recorded at daily, monthly, and yearly intervals. Air quality was evaluated by comparing the annual average concentrations and the maximum daily concentrations of PM10 and PM2.5 with the World Health Organization (WHO) and national standards. The results showed that the limits established in the WHO guidelines and the national standards were systematically exceeded at all the study sites. The highest concentrations of both PM10 and PM2.5 were observed during the fall and winter months (April to September), i.e., the cold period of the year, whereas the lowest concentrations were recorded in the spring and summer months (October to March), i.e., the warm period of the year. Analysis of variance (ANOVA) of the data collected in the warm and cold periods showed that all stations in this study exhibited statistically significant differences between these two periods. During cold periods, burning firewood for heating produces emissions that are a main source of PM. Furthermore, firewood is primarily burned at night when the lowest temperatures occur and when the atmospheric conditions are generally unfavorable for dispersion; thus, pollution accumulates above cities. The levels of PM2.5, the most important type of pollution, exceeded the limit established by the WHO on at least one-third of the days of the year (>120 days) in the cities of Rancagua, Rengo, Curicó, Talca, Chillan, Los Angeles, Temuco, Valdivia, Osorno, Puerto Montt and Coyhaique. Therefore in the cities in southern Chile, the population is exposed to particulate matter concentrations that can have negative health impacts. To improve the air quality conditions in the studied cities, research on heaters and combustion techniques should be promoted, home energy efficiency should be increased to reduce firewood consumption, the firewood certification process should be improved at the national level with a better auditing processes, and the introduction of alternative fuels should be considered for greater energy efficiency at competitive costs.
... The Chilean regulation has only set the particles air quality index (ICAP in Spanish) for particulate matter (PM 10 and PM 2.5 ) and the gases air quality index (ICAG in Spanish) for O 3 and other gases. These indexes are defined to help recognize episodes of atmospheric pollution (Diaz-Robles et al., 2008;Díaz-Robles et al., 2011. Recently, two actions have been initiated by Chilean regulations: (i) a regional PM10 restriction to improve air quality in Temuco (implemented in 2010) and (ii) a national action on the Chilean standard for PM 2.5 (implemented January 1, 2012). ...
... In fact, almost 80% of the population uses wood for cooking or heating in winter, and it is estimated that 93% of PM 10 annual emissions originate from RWC. In spite that Temuco was declared a non-attainment area due to PM10 in 2005, and whose Atmospheric Decontamination Plan was enacted in 2010 by the President of Chile, still there are no visual advances towards the reduction of days that surpass regulation (Díaz-Robles et al., 2011). On the contrary, a steady increase of PM 10 is still seen, Fig. 1. ...
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Temuco and Pudahuel are two urban areas in Chile that are among the highest in particulate matter (PM10) air pollution in Chile. In fact, Temuco is also classified as one of the most polluted cities in Latin America by the World Health Organization. Both cities show important differences in the sources of this PM10 pollution. For Temuco, a southern city, the main source is the residential wood combustion (RWC), and for Pudahuel, located in the central zone, the main sources are mobile and point sources. The relationship between PM10 air pollution and health effects measured as the daily number of deaths and hospital admissions for cardiovascular and respiratory causes was determined. The Air Pollution Health Effects European Approach (APHEA-2) protocol was followed, and a multivariate Poisson regression model with gam.exact algorithm was fitted for these cities during 2001-2006. The results show that PM10 had a significant association with daily mortality, where the relative risks (RR) for cardio respiratory mortality of the elderly age group was 1.0126 [95% (CI: 1.0004 – 1.0250)] at Temuco and 1.0086 [95% (CI: 1.0007 – 1.0165)] for Pudahuel when PM10 increased by 10 μg/m3. For the hospital admissions due to chronic obstructive pulmonary disease (COPD), the RR were 1.0198 [95% (CI: 1.0030 – 1.0369)] at Temuco and 1.0097 [95% (CI: 1.0000 – 1.0204)] at Pudahuel. There is evidence in these cities of positive relationships between ambient particulate levels and the rates of mortality and morbidity for cardiovascular and respiratory causes; being the excess risk 47% and 104.1% higher in Temuco than Pudahuel for cardiorespiratory mortality of the elderly population and COPD hospital admissions, respectively. These results demonstrate that there is greater risk when people are exposed to air polluted with wood smoke.
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Background: Annually, acute bronchiolitis (AB) occurrence peaks during winter and is probably associated with air pollution. Aim: To relate the number of ambulatory consultations, emergency and hospital admission due to AB with climatic factors and air pollution. Patients and methods: Patients of less than 1 year old with AB that consulted to outpatient clinics, the emergency room or were admitted to the Pediatrics ward of the Catholic University Hospital, were enrolled. Information about respiratory syncytial virus (RSV) was obtained,from the Catholic University Medical Investigation Center. Indices of air pollution such as particulate matters of less than 10 microns/m(3) (PM 10), of less than 2.5 microns/m(3) (PM 2.5), CO, SO3 and O-3 were obtained from the Metropolitan Environmental Service: Temperature, humidity and precipitations were obtained from the Chilean Meteorological Service. Results: Ninety nine consultations in outpatient clinics and 442 in emergency rooms were collected (55% male, mean age 4.8 months). One hundred fifty two were admitted (34.4%). Thirty percent of children consulting in emergency rooms were younger than 3 months and 43% of them were hospitalized. The RSV study was made in 307 patients and 52% were positive. There was a higher rate of hospital admissions among RSV positive than RSV negative patients (52.5 and 22% respectively, p < 0.00). No association between environmental variables or air pollution and the number of consultations was observed. Young age and smoking inside the household were the main risk,factors,for hospital admission due to acute bronchiolitis. Conclusions: Environmental variables did not influence the number of cases of acute brochiolitis. Young age and exposure to tobacco smoke were risk,factors for hospital admission (Rev Med Chile 2003; 131: 1117-22).
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The optical absorption coefficient, particulate matter with an aerodynamic diameter <2.5 mum, and elemental carbon (EC) have been measured simultaneously during winter and spring of 2000 in the western part of Santiago, Chile (Pudahuel district). The optical measurements were carried out with a low-cost instrument recently developed at the University of Santiago. From the data, a site-specific mass absorption coefficient of 4.45 +/- 0.01 m(2)/g has been found for EC. In addition, a mass absorption coefficient of 1.02 +/- 0.03 m(2)/g has been obtained for PM2.5. These coefficients can be used during the colder months (May-August) to obtain EC concentration or PM2.5 from a measurement of the light absorption coefficient (sigma(a)). The high correlation that has been found between these variables indicates that a. is a good indicator of the degree of contamination of urbanized areas. The data also show an increase in PM2.5 and EC concentration during winter and an increase in the ratio of EC to PM2.5. When the EC/PM2.5 ratio is calculated during rush hour (7:00 a.m.-11:00 a.m.) and during part of the night (9:00 p.m.-2:00 a.m.), it is found that the increase is caused by higher concentration levels of EC at night. These results suggest that the rise in the EC concentration is caused by emissions from heating and air mass transport of pollution from other parts of the city, while traffic contribution remains approximately constant.
Background: Indoor pollution can be an important risk factor for human health, considering that people spend more than 60% of their time in their houses. Aim: To investigate indoor pollution in a zone of extreme poverty in metropolitan Santiago. Material and methods: During 24h, carbon monoxide (CO), sulfur dioxide (SO2), respirable particulate matter (PM10), polycyclic aromatic hydrocarbons absorbed in PM5, temperature and humidity, were measured in the interior of 24 houses in La Pintana, Santiago. Results: The higher pollutant concentrations were observed during hours when heating was used, in houses that used coal (mean PM10, 250 mug/m(3), CO 42 ppm, SO2 192 pph) or firewood (mean PM10 489 mug/m(3), CO 57 ppm, SO2 295 pph). In all houses, polycyclic aromatic hydrocarbons were detected and they came from the interior of the house and not from external filtered air. Coal, firewood and cigarette smoke were important sources of carcinogenic and kerosene and gas were sources of non carcinogenic polycyclic aromatic hydrocarbons. Conclusions: In the houses studied, the population was exposed to an accumulation of highly toxic pollutants, caused by a lack of ventilation. A high relative humidity also contributed to the growth of biological pollutants (Rev Med Chile 2001; 129: 33-42).
Estimates of air pollution removal by the urban forest have mostly been based on mean values of forest structure variables for an entire city. However, the urban forest is not uniformly distributed across a city because of biophysical and social factors. Consequently, air pollution removal function by urban vegetation should vary because of this spatial heterogeneity. This paper presents a different approach to evaluate how the spatial heterogeneity of the urban forest influences air pollution removal at the socioeconomic subregion scale. estimated using measured urban forest structure data from three socioeconomic subregions in Santiago, Chile. Dry deposition was estimated using hourly climate, mixing height, and pollutant concentration data. Pollution removal rates among the three socioeconomic subregions were different because of heterogeneous urban forest structure and pollution concentrations. Air pollution removal per square meter of tree cover was greatest in the low socioeconomic subregion. Pollution removal during 1997–1998 was different from 2000 to 2001 due to pollution concentration differences. Seasonal air quality improvement also differed among the subregions. Results can be used to design management alternatives at finer administrative scales such as districts and neighborhoods that maximize the pollution removal rates by the urban forest in a subregion. Policies that affect the functionality of urban forest structure must consider spatial heterogeneity and scale when making region-wide recommendations. Similarly, when model-ing the functionality of the urban forest, models must capture this spatial heterogeneity for inter-city comparisons.
In major urban areas, air pollution impact on health is serious enough to include it in the group of meteorological variables that are forecast daily. This work focusses on the comparison of different forecasting systems for daily maximum ozone levels at Santiago, Chile. The modelling tools used for these systems were linear time series, artificial neural networks and fuzzy models. The structure of the forecasting model was derived from basic principles and it includes a combination of persistence and daily maximum air temperature as input variables. Assessment of the models is based on two indices: their ability to forecast well an episode, and their tendency to forecast an episode that did not occur at the end (a false positive). All the models tried in this work showed good forecasting performance, with 70–95% of successful forecasts at two monitor sites: Downtown (moderate impacts) and Eastern (downwind, highest impacts). The number of false positives was not negligible, but this may be improved by expressing the forecast in broad classes: low, average, high, very high impacts; the fuzzy model was the most reliable forecast, with the lowest number of false positives among the different models evaluated. The quality of the results and the dynamics of ozone formation suggest the use of a forecast to warn people about excessive exposure during episodic days at Santiago.
Few studies have been done on indoor air pollution in areas of extreme poverty in developing countries. In such countries, for economic reasons, people use solid fuel for cooking and heating fuels which by incomplete combustion generate high levels of toxic pollutants. These represent an important risk factor for human health. We have investigated the levels of carbon mon oxide (CO), sulphur dioxide (SO2), respirable particulate matter (PM10), polycyclic aromatic hydrocarbons (PAHs) and mutagenicity in the PM5 fraction, as well as tempera ture and humidity, in the interior of 24 houses in La Pinta na, Santiago. In addition, we have conducted a survey about symptoms, signs and respiratory diseases possi bly associated with socio-economic factors in the area. The survey showed that in children younger than 2 years, most respiratory diseases occur during winter (75%), the most frequent complaint being bronchitis (62%) and obstructive bronchitis (50%). The higher pol lutant concentrations were observed during heating hours, in houses that used coal (mean PM 10 250 μg.m-3, CO 42 ppm, SO2 192 ppb) or firewood (mean PM10 489 μg.m-3, CO 57 ppm, SO 2 295 ppb). PAHs were detected in all houses and we concluded that they came from inside the house and not from outdoor infiltration. Coal, firewood and cigarette smoke were important sources of mutagenic and carcinogenic PAHs, whereas kerosene and gas contributed mainly to the non-carcino genic PAH fraction. In the houses studied, the population was exposed to levels of toxic pollutants that are much higher than those found outdoors in the highly polluted city of Santiago. In addition, overcrowding, excessive indoor humidity, very low indoor temperatures when the heating system was turned off, the presence of domestic animals, cats and dogs indoors and general lack of hygiene (with attendant bacteria and fungi) are risk fac tors to explain the high incidence of respiratory diseases in children.
Santiago, Chile has developed a significant problem of atmospheric contamination with high levels of total suspended aerosol particles consisting of a high PM-10 fraction. This is associated with a growing economy, rapid urban expansion, increasing rate of motorization and expanding industrial activity. The organic contribution to atmospheric suspended particles (PM-10) in Santiago has been quantitated, characterized and related to its input sources in this report. The average organic content of 38% is significantly lower from pre-regulatory levels of 71% and in the range reported for other urban centers. Molecular markers indicate that a predominant proportion of the organic compounds associated with the particluate matter are derived from uncombusted diesel, uncombusted lubricating oil and other petrochemical fuel use. A significant organic contribution from natural plant wax hydrocarbons is also detected, suggesting biomass fuel use, open burning of vegetation in incidental fires or agricultural practices and resuspension of weathered vegetation debris. Aromatic hydrocarbon fractions indicate the presence of pyrogenic PAH formed by high-temperature combustion processes of petrochemical fuels with a significant contribution of retene indicative of conifer wood combustion. Maturity indicators, based on methylphenanthrene indexes, also indicate the simultaneous concurrence of high- and low-temperature combustion processes and confirm a significant contribution of non-petrochemical-sourced organic compounds to the atmospheric aerosols. Benzopyrene ratios indicate that Santiago aerosols are freshly generated and do not have an extensive solar exposure. The present study provides a reference baseline for the organic components relating to air quality in Santiago, and will permit the assessment of the environmental effectiveness of corrective measures related to energy usage and transport administration.
Because of the high levels of pollution that Santiago de Chile experiences every year in winter, the government has set up an air quality monitoring network. Information from this network is employed to alert people about the quality of air and to enforce several control strategies in order to limit pollution levels. The monitoring network has 8 stations that measure PM10, carbon monoxide (CO), sulphur dioxide (SO2), ozone (O3) and meteorological parameters. Some stations also measure nitrogen mono- and dioxide (NOx), fine particles (PM2.5) and carbon. In this study we have examined the PM10 and O3 data generated by this network in the year 2000 in order to determine the seasonal trends and spatial distribution of these pollutants over a year's period. The results show that concentration levels vary with the season, with PM10 being higher in winter and O3 in summer. All but one station, show a peak in PM10 at 8:00 indicating that during the rush hour there is a strong influence from traffic, however, this influence is not seen during the rest of the day. In winter, the PM10 maximum occurs at 24:00 h in all stations but Las Condes. This maximum is related to decreased wind speed and lower altitude of the inversion layer. The fact that Las Condes station is at a higher altitude than the others and it does not show the PM10 increase at night, suggest that the height of the inversion layer occurs at lower altitude. Cluster analysis was applied to the PM10 and O3 data, and the results indicate that the city has four large sectors with similar pollution behavior. The fact that both pollutants have similar distribution is a strong indication that the concentration levels are primarily determined by the topographical and meteorological characteristics of the area and that pollution generated over the city is redistributed in four large areas that have similar meteorological and topographical conditions.
The leakage of unburned liquefied petroleum gas (LPG) is a major source of urban nonmethane hydrocarbons (NMHCs) in the air of Santiago, Chile. Roughly 5% of the LPG that is sold in Santiago leaks in its unburned form to the atmosphere. Because of the leakage, propane is the most abundant NMHC in Santiago's air, even under heavy traffic conditions. NMHCs are an important precursor to the formation of ground-level ozone, and the LPG leakage may contribute as much as 15% to the excess ozone levels in Santiago. Improvement to the local air quality may be obtained by lowering the rates of LPG leakage, and by minimizing the use of alkene-rich LPG formulations.