Surface Indices of Wind, Stability, and Turbulence at a Highly Polluted Urban Site in Santiago, Chile, and their Relationship with Nocturnal Particulate Matter Concentrations

Muñoz, Ricardo C.; Corral, Marcelo J.

doi:10.4209/aaqr.2017.05.0190

Cited by 21 publications

(15 citation statements)

References 24 publications

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“…The difference between the wind speed measured at the sampling sites is based on the greater turbulence of air masses produced in the eastern part of the region where the urban receptor site is located. Previous research has shown that higher wind speeds in this area occur when cold air masses begin to descend from the Andes during the evening hours (Muñoz and Corral, 2017).…”

Section: Discussionmentioning

confidence: 87%

“…The geographical and climatic characteristics of the SMR have been associated to a large extent with unfavorable conditions for the dispersion of air pollutants (Rutllant and Garreaud, 1995;Schmitz, 2005;Ragsdale et al, 2013;Muñoz and Corral, 2017). Approximately 85% of the SMR surface is mountainous terrain that blocks the air circulation in the lower atmospheric layers.…”

Section: Introductionmentioning

confidence: 99%

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Spatiotemporal Variation in Composition of Submicron Particles in Santiago Metropolitan Region, Chile

Tagle¹,

Reyes²,

Vásquez³

et al. 2018

Front. Environ. Sci.

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The chemical composition of submicron particles (aerodynamic diameter D a < 1.0 µm) was investigated at three locations in the Santiago Metropolitan Region (SMR), Chile. Measurements campaigns were conducted in winter and spring 2016, at representative sites of a rural, urban, and urban receptor environment. Instrumentation consisted of an optical analyzer to determine Black Carbon (BC) and the Aerosol Chemical Speciation Monitor (ACSM) to measure concentrations of particulate chloride (Cl − ), nitrate (NO − 3 ), sulfate (SO 2− 4 ), ammonium (NH + 4 ), and non-refractory carbonaceous species (organics). Complementary data, such as ozone concentration and meteorological parameters were obtained from the public air quality network. Results showed that in both the winter and spring seasons the organics predominated in the mass of submicron particles. This fraction was followed in decreasing order by NO − 3 , NH + 4 , BC, SO 2− 4 , and Cl − . The highest average organics concentrations were measured in winter at the urban (32.2 µg m −3 ) and urban receptor sites (20.1 µg m −3 ). In winter, average concentrations of both NO − 3 and NH + 4 were higher at the urban receptor site (12.3 and 4.5 µg m −3 , respectively) when compared to the urban site (6.4 and 3.1 µg m −3 , respectively). In general, all the measured species were present in higher concentrations during winter, excepting SO 2− 4 , which was the only one that increased during spring. The transition toward spring was also associated with an acidification of the aerosol at the rural and urban receptor site, while at the urban site the aerosol was observed alkaline. The highest average ozone concentration during both the winter and spring seasons were recorded at the urban receptor site (7.2 and 24.0 ppb, respectively). The study reports data showing that the atmosphere in the SMR has a considerable load of particulate organic compounds, NO − 3 and NH + 4 , which are in higher concentrations at urban sites during the winter season. Based on wind patterns and the hourly profiles of chemical species, the study suggests that during daytime the polluted air masses from the urban center can move to the northeast part of the region (namely urban receptor site) leading to the formation of submicron particles as well as photochemical ozone.

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Section: Discussionmentioning

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Spatiotemporal Variation in Composition of Submicron Particles in Santiago Metropolitan Region, Chile

Tagle¹,

Reyes²,

Vásquez³

et al. 2018

Front. Environ. Sci.

View full text Add to dashboard Cite

show abstract

“…Due to its topography, Santiago experiences unfavorable conditions for the dispersion of air pollutants. The geographic and meteorological factors that affect air quality in this city have been extensively described (Rutllant and Garreaud, 1995;Schmitz, 2005;Ragsdale et al 2013;Toro et al 2014;Muñoz and Corral, 2017).…”

Section: Field Testsmentioning

confidence: 99%

Field performance of a low-cost sensor in the monitoring of particulate matter in Santiago, Chile

Tagle

Rojas

Reyes

et al. 2020

Environ Monit Assess

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Integration of low-cost air quality sensors with the internet of things (IoT) has become a feasible approach towards the development of smart cities. Several studies have assessed the performance of low-cost air quality sensors by comparing their measurements with reference instruments. We examined the performance of a low-cost IoT particulate matter (PM 10 and PM 2.5 ) sensor in the urban environment of Santiago, Chile. The prototype was assembled from a PM 10 -PM 2.5 sensor (SDS011), a temperature and relative humidity sensor (BME280) and an IoT board (ESP8266/ Node MCU). Field tests were conducted at three regulatory monitoring stations during the 2018 austral winter and spring seasons. The sensors at each site were operated in parallel with continuous reference air quality monitors (BAM 1020 and TEOM 1400) and a filterbased sampler (Partisol 2000i). Variability between sensor units (n = 7) and the correlation between the sensor and reference instruments were examined. Moderate inter-unit variability was observed between sensors for PM 2.5 (normalized root-mean-square error 9-24%) and PM 10 (10-37%). The correlations between the 1-h average concentrations reported by the sensors and continuous monitors were higher for PM 2.5 (R 2 0.47-0.86) than PM 10 (0.24-0.56). The correlations (R 2 ) between the 24-h PM 2.5 averages from the sensors and reference instruments were 0.63-0.87 for continuous monitoring and 0.69-0.93 for filter-based samplers. Correlation analysis revealed that sensors tended to overestimate PM concentrations in high relative humidity (RH > 75%) and underestimate when RH was below 50%. Overall, the prototype evaluated exhibited adequate performance and may be potentially suitable for monitoring daily PM 2.5 averages after correcting for RH.

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“…Meteorological conditions sometimes determine air pollution situations, since they may aggravate pollution episodes, such as the recirculation of air parcel trajectories studied in Los Angeles [ 15 ]. However, certain meteorological conditions may also improve air quality, with the inverse relationship between particulate matter concentrations and the ventilation factor (the product of wind speed at 10 m and the mixed-layer height estimate) observed in Santiago City, Chile, being one noticeable example [ 16 ].…”

Section: Introductionmentioning

confidence: 99%

Key Points in Air Pollution Meteorology

Pérez

García

Sánchez

et al. 2020

IJERPH

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Although emissions have a direct impact on air pollution, meteorological processes may influence inmission concentration, with the only way to control air pollution being through the rates emitted. This paper presents the close relationship between air pollution and meteorology following the scales of atmospheric motion. In macroscale, this review focuses on the synoptic pattern, since certain weather types are related to pollution episodes, with the determination of these weather types being the key point of these studies. The contrasting contribution of cold fronts is also presented, whilst mathematical models are seen to increase the analysis possibilities of pollution transport. In mesoscale, land–sea and mountain–valley breezes may reinforce certain pollution episodes, and recirculation processes are sometimes favoured by orographic features. The urban heat island is also considered, since the formation of mesovortices determines the entry of pollutants into the city. At the microscale, the influence of the boundary layer height and its evolution are evaluated; in particular, the contribution of the low-level jet to pollutant transport and dispersion. Local meteorological variables have a major influence on calculations with the Gaussian plume model, whilst some eddies are features exclusive to urban environments. Finally, the impact of air pollution on meteorology is briefly commented on.

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Surface Indices of Wind, Stability, and Turbulence at a Highly Polluted Urban Site in Santiago, Chile, and their Relationship with Nocturnal Particulate Matter Concentrations

Cited by 21 publications

References 24 publications

Spatiotemporal Variation in Composition of Submicron Particles in Santiago Metropolitan Region, Chile

Spatiotemporal Variation in Composition of Submicron Particles in Santiago Metropolitan Region, Chile

Field performance of a low-cost sensor in the monitoring of particulate matter in Santiago, Chile

Key Points in Air Pollution Meteorology

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