Francisco Cereceda-Balic

Source apportionment of PM10 and PM2.5 in five Chilean cities using factor analysis.

ABSTRACT Chile is a fast-growing country with important industrial activities near urban areas. In this study, the mass and elemental concentrations of PM10 and PM2.5 were measured in five major Chilean urban areas. Samples of particles with diameter less than 10 um (PM10) and 2.5 um (PM2.5) were collected in 1998 in Iquique (northern Chile), Valparaiso, Vina del Mar, Rancagua (central Chile), and Temuco (southern Chile). Both PM10 and PM25 annual mean concentrations (PM10: 56.9-77.6 u,g/m3; PM25: 22.4-42.6 u.g/m3) were significantly higher than the corresponding European Union (EU) and U.S. Environmental Protection Agency (EPA) air quality standards. Moreover, the 24-hr PM10 and PM25 U.S. standards were exceeded infrequently for some of the cities (Rancagua and Valparaiso).

Trends in the elemental composition of fine particulate matter in Santiago, Chile, from 1998 to 2003.

Abstract Santiago, Chile, is one of the most polluted cities in South America. As a response, over the past 15 yr, numerous pollution reduction programs have been implemented by the environmental authority, Comisión Nacional del Medio Ambiente. This paper assesses the effectiveness of these interventions by examining the trends of fine particulate matter (PM2.5) and its associated elements. Daily fine particle filter samples were collected in Santiago at a downtown location from April 1998 through March 2003. Additionally, meteorological variables were measured continuously. Annual average concentrations of PM2.5decreased only marginally, from 41.8 μg/m3for the 1998–1999 period to 35.4 μg/m3for the 2002–2003 period. PM2.5concentrations exceeded the annual U.S. Environmental Protection Agency standard of 15 μg/m3. Also, approximately 20% of the daily samples exceeded the old standard of 65 μg/m3, whereas approximately half of the samples exceeded the new standard of 35 μg/m3(effective in 2006). Mean PM2.5levels measured during the cold season (April through September) were three times higher than those measured in the warm season (October through March). Particulate mass and elemental concentration trends were investigated using regression models, controlling for year, month, weekday, wind speed, temperature, and relative humidity. The results showed significant decreases for Pb, Br, and S concentrations and minor but still significant decreases for Ni, Al, Si, Ca, and Fe. The larger decreases were associated with specific remediation policies implemented, including the removal of lead from gasoline, the reduction of sulfur levels in diesel fuel, and the introduction of natural gas. These results suggest that the pollution reduction programs, especially the ones related to transport, have been effective in reducing various important components of PM2.5. However, particle mass and other associated element levels remain high, and it is thus imperative to continue the efforts to improve air quality, particularly focusing on industrial sources.

Miniaturized voltammetric stripping on screen printed gold electrodes for field determination of copper in atmospheric deposition.

The applicability of commercial screen-printed gold electrodes (SPGEs) connected to a portable potentiostat and a laptop has been explored to optimize a new square wave anodic stripping voltammetric method for on-site determination of soluble Cu(II) in atmospheric deposition samples taken around an industrial complex. Electrode conditioning procedures, chemical and instrumental variables have been optimized to develop a reliable method capable of measuring dissolved copper with a detection limit of 3.7 ng mL(-1), useful for pollution monitoring or screening purposes. The proposed method was tested with the SLRS-5 River Water for Trace Metals (recoveries 109.9-113.1%) and the SPS-SW2 Batch 121 Elements in Surface Waters (recoveries 93.2-97.6%). The method was applied to soluble Cu(II) measurement in liquid samples taken by a total atmospheric deposition collector modified with a quartz filter for soluble and insoluble elemental speciation. The voltammetric measurements on field samples were tested in the lab by a reference ICP-MS method, with good agreement. The proposed method proved capability for field operation during a two weeks monitoring campaign.

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

This study addresses human health concerns in the city of Temuco that are attributed to wood smoke and related pollutants associated with wood burning activities that are prevalent in Temuco. Polycyclic Aromatic Hydrocarbons (PAHs) were measured in air across urban and rural sites over three seasons in Temuco using polyurethane foam (PUF) disk passive air samplers (PUF-PAS). Concentrations of ΣPAHs (15 congeners) in air ranged from BDL to ∼70 ng m(-3) and were highest during the winter season, which is attributed to emissions from residential heating by wood combustion. The results for all three seasons showed that the PAH plume was widespread across all sites including rural sites on the outskirts of Temuco. Some interesting variations were observed between seasons in the composition of PAHs, which were attributed to differences in seasonal point sources. A comparison of the PAH composition in the passive samples with active samples (gas+particle phase) from the same site revealed similar congener profiles. Overall, the study demonstrated that the PUF disk passive air sampler provides a simple approach for measuring PAHs in air and for tracking effectiveness of pollution control measures in urban areas in order to improve public health.

Obtaining polycyclic aromatic hydrocarbon concentration ratios and molecular markers for residential wood combustion: Temuco, a case study

It is known that residential wood combustion (RWC) is an important source of fine particle emissions. The purpose of this work was to characterize the chemical composition of the particulate matter present in the Temuco urban atmosphere during winter, specifically the polycyclic aromatic hydrocarbon (PAH) profile, because PAHs are considered to be among the key compounds in particulate matter toxicity. During the 2008 winter monitoring campaign, samples of particulate matter with aerodynamic diameters of ≤10 (PM10) and ≤2.5 (PM2.5) μm were taken on days with contamination episodes. Sixteen U.S. Environmental Protection Agency (EPA) PAH compounds were extracted with toluene and determined by gas chromatography–mass spectrometry (GC-MS). The results show that phenantrene was the predominant compound associated with particulate matter, at a concentration range between 300 and 600 ng m−3, 18 times higher than the second most abundant PAH compound. High-molecular-mass compounds such as dibenz[a,h]anthracene, benzo[g,h,i]perylene, and indeno[1,2,3,c,d]pyrene were also found, but they were minorities in the set. It was recognized from the PAH concentration ratios of the Temuco atmospheric aerosol that the main contamination source was in fact residential wood combustion; although not all the concentration ratios evaluated match the reported reference values, probably due to the kind of biomass used, the characteristics of Chilean heating appliances and climate. Implications: The study results suggest that if molecular markers (MMs) and concentration ratios (CRs) are dependent on the type of firewood and combustion processes specific to each location, among others factors, then the values of these indicators could be applicable with caution between different areas, although not necessarily they must be totally in accord. Moreover, having representative values of MM and CR of each place, it will achieve a better estimation of the source importance and concentrate the monitoring and the control strategies. Regulatory organizations in each country can have more reliable information and optimize financial and human resources, enabling it to reduce air pollution and improve the health of population.

Long-term assessment of ecological risk from deposition of elemental pollutants in the vicinity of the industrial area of Puchuncaví-Ventanas, central Chile

UNLABELLED The present work investigates soil pollution by elemental contaminants and compares ecological risk indexes related to industrial activities for the case study of Puchuncaví-Ventanas: a relevant industrial zone located in central Chile. Selected elements (As, Pb, Cd, Ni, Hg, V, Mn, Zn, Sr, Sb, Cr, Co, Cu, K, and Ba) were analyzed during a long-term period (yearly sampling campaigns during 2007-2011), at 5 sampling stations representing different degrees of impact. PCA and cluster analysis allowed identifying a copper smelter and a coal-fired power plant complex as major pollution sources. Geoaccumulation index (I geo), enrichment factor (EF), contamination factor (Cf), contamination degree (C deg), and integrated pollution index (IPI) are critically discussed for quantitative ecological risk assessment. I geo, EF and Cf indexes are producing comparable environmental information, showing moderate to high pollution risks in the area that demands further monitoring and adoption of prevention and remediation measures. CAPSULE Long term assessment of elemental pollution around an industrial area. New insight on ecological risk indexes for trace element pollution in soils, by critical comparison among them.

Use of the light absorption coefficient to monitor elemental carbon and PM2.5- Example of Santiago de Chile

Abstract The optical absorption coefficient, particulate matter with an aerodynamic diameter <2.5 μm, 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 m2/g has been found for EC. In addition, a mass absorption coefficient of 1.02 ± 0.03 m2/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 (σa). The high correlation that has been found between these variables indicates that σa 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.

Emission factors for PM2.5, CO, CO2, NOx, SO2 and particle size distributions from the combustion of wood species using a new controlled combustion chamber 3CE

The objective of this research was to determine emission factors (EF) for particulate matter (PM2.5), combustion gases and particle size distribution generated by the combustion of Eucalyptus globulus (EG), Nothofagus obliqua (NO), both hardwoods, and Pinus radiata (PR), softwood, using a controlled combustion chamber (3CE). Additionally, the contribution of the different emissions stages associated with the combustion of these wood samples was also determined. Combustion experiments were performed using shaving size dried wood (0% humidity). The emission samples were collected with a tedlar bag and sampling cartridges containing quartz fiber filters. High reproducibility was achieved between experiment repetitions (CV<10%, n=3). The EF for PM2.5 was 1.06gkg-1 for EG, 1.33gkg-1 for NO, and 0.84gkg-1 for PR. Using a laser aerosol spectrometer (0.25-34μm), the contribution of particle emissions (PM2.5) in each stage of emission process (SEP) was sampled in real time. Particle size of 0.265μm were predominant during all stages, and the percentages emitted were PR (33%), EG (29%), and NO (21%). The distributions of EF for PM2.5 in pre-ignition, flame and smoldering stage varied from predominance of the flame stage for PR (77%) to predominance of the smoldering stage for NO (60%). These results prove that flame phase is not the only stage contributing to emissions and on the contrary, pre-ignition and in especial post-combustion smoldering have also very significant contributions. This demonstrates that particle concentrations measured only in stationary state during flame stage may cause underestimation of emissions.

Spatial gradient of human health risk from exposure to trace elements and radioactive pollutants in soils at the Puchuncaví-Ventanas industrial complex, Chile ☆

The Punchuncaví Valley in central Chile, heavily affected by a range of anthropogenic emissions from a localized industrial complex, has been studied as a model environment for evaluating the spatial gradient of human health risk, which are mainly caused by trace elemental pollutants in soil. Soil elemental profiles in 121 samples from five selected locations representing different degrees of impact from the industrial source were used for human risk estimation. Distance to source dependent cumulative non-carcinogenic hazard indexes above 1 for children (max 4.4 - min 1.5) were found in the study area, ingestion being the most relevant risk pathway. The significance of health risk differences within the study area was confirmed by statistical analysis (ANOVA and HCA) of individual hazard index values at the five sampling locations. As was the dominant factor causing unacceptable carcinogenic risk levels for children (<10-4) at the two sampling locations which are closer to the industrial complex, whereas the risk was just in the tolerable range (10-6 - 10-4) for children and adults in the rest of the sampling locations at the study area. Furthermore, we assessed gamma ray radiation external hazard indexes and annual effective dose rate from the natural radioactivity elements (226Ra, 232Th and 40K) levels in the surface soils of the study area. The highest average values for the specific activity of 232Th (31 Bq kg-1), 40K (615 Bq kg- 1), and 226Ra (25 Bq kg-1) are lower than limit recommended by OECD, so no significant radioactive risk was detected within the study area. In addition, no significant variability of radioactive risk was observed among sampling locations.

Temporal and spatial variation of trace elements in atmospheric deposition around the industrial area of Puchuncaví-Ventanas (Chile) and its influence on exceedances of lead and cadmium critical loads in soils

Fractionation of elemental contents in atmospheric samples is useful to evaluate pollution levels for risk assessment and pollution sources assignment. We present here the main results of long-term characterization of atmospheric deposition by using a recently developed atmospheric elemental fractionation sampler (AEFS) for major and trace elements monitoring around an important industrial complex located in Puchuncaví region (Chile). Atmospheric deposition samples were collected during two sampling campaigns (2010 and 2011) at four sampling locations: La Greda (LG), Los Maitenes (LM), Puchuncaví (PU) and Valle Alegre (VA). Sample digestion and ICP-MS gave elements deposition values (Al, As, Ba, Cd, Co, Cu, Fe, K, Mn, Pb, Sb, Ti, V and Zn) in the insoluble fraction of the total atmospheric deposition. Results showed that LG location, the closest location to the industrial complex, was the more polluted sampling site having the highest values for the analyzed elements. PU and LM were the next more polluted and, finally, the lowest elements concentrations were registered at VA. The application of Principal Component Analysis and Cluster Analysis identified industrial, traffic and mineral-crustal factors. We found critical loads exceedances for Pb at all sampling locations in the area affected by the industrial emissions, more significant in LG close to the industrial complex, with a trend to decrease in 2011, whereas no exceedances due to atmospheric deposition were detected for Cd.