Urban Atmospheric Ammonia in Santiago City, Chile

Toro, Richard A.; Canales, Mauricio; Flocchini, Robert G.; Morales, Raúl G. E.; Leiva, A G Manuel

doi:10.4209/aaqr.2012.07.0189

Cited by 22 publications

(19 citation statements)

References 25 publications

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“…This is particularly true when comparing with cities in South Asia (e.g., Delhi in India and Lahore in Pakistan), where there is a lack of basic sanitation facilities (e.g., public flush toilets), and significant animal populations (such as cows) coexist with people in urban areas. The higher NH 3 concentrations measured at surface sites in South Asia are consistent with spatial patterns from recent satellite remote sensing observations (Clarisse et al, 2009;Van Damme et al, 2014).…”

Section: Temporal Evolution Of Nh 3 Concentrationssupporting

confidence: 86%

The importance of vehicle emissions as a source of atmospheric ammonia in the megacity of Shanghai

Zou²,

et al. 2016

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Abstract. Agricultural activities are a major source contributing to NH3 emissions in Shanghai and most other regions of China; however, there is a long-standing and ongoing controversy regarding the contributions of vehicle-emitted NH3 to the urban atmosphere. From April 2014 to April 2015, we conducted measurements of a wide range of gases (including NH3) and the chemical properties of PM2.5 at hourly resolution at a Shanghai urban supersite. This large data set shows NH3 pollution events, lasting several hours with concentrations 4 times the annual average of 5.3 µg m−3, caused by the burning of crop residues in spring. There are also generally higher NH3 concentrations (mean ± 1 σ) in summer (7.3 ± 4.9 µg m−3; n = 2181) because of intensive emissions from temperature-dependent agricultural sources. However, the NH3 concentration in summer was only an average of 2.4 µg m−3 or 41 % higher than the average NH3 concentration of other seasons. Furthermore, the NH3 concentration in winter (5.0 ± 3.7 µg m−3; n = 2113) was similar to that in spring (5.1 ± 3.8 µg m−3; n = 2198) but slightly higher, on average, than that in autumn (4.5 ± 2.3 µg m−3; n = 1949). Moreover, other meteorological parameters like planetary boundary layer height and relative humidity were not major factors affecting seasonal NH3 concentrations. These findings suggest that there may be some climate-independent NH3 sources present in the Shanghai urban area. Independent of season, the concentrations of both NH3 and CO present a marked bimodal diurnal profile, with maxima in the morning and the evening. A spatial analysis suggests that elevated concentrations of NH3 are often associated with transport from regions west–northwest and east–southeast of the city, areas with dense road systems. The spatial origin of NH3 and the diurnal concentration profile together suggest the importance of vehicle-derived NH3 associated with daily commuting in the urban environment. To further examine vehicular NH3 emissions and transport, sampling of the NH3 concentration was performed in (from the entrance to the exit of the tunnel) and out (along a roadside transect spanning 310 m perpendicular to the tunnel) of a heavily trafficked urban tunnel during the spring of 2014. NH3 concentrations in the tunnel exit were over 5 and 11 times higher than those in the tunnel entrance and in the ambient air, respectively. Based on the derived mileage-based NH3 emission factor of 28 mg km−1, a population of 3.04 million vehicles in Shanghai produced around 1300 t NH3 in 2014, which accounts for 12 % of total NH3 emissions in the urban area. Collectively, our results clearly show that vehicle emissions associated with combustion are an important NH3 source in Shanghai urban areas and may have potential implications for PM2.5 pollution in the urban atmosphere.

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Section: Temporal Evolution Of Nh 3 Concentrationssupporting

confidence: 86%

The importance of vehicle emissions as a source of atmospheric ammonia in the megacity of Shanghai

Zou²,

et al. 2016

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“…On the other hand, ammonia has been described as highly abundant at the urban site, due proximity to major sources, such as agricultural areas, sewage treatment plants, and industries (Toro Araya et al, 2014a). At this site, the increase in ammonium concentration observed in spring could be related to the greater alkalization observed in the urban aerosol during that season.…”

Section: Discussionmentioning

confidence: 85%

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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“…In Santiago, concentrations of sulfate were low because of air quality regulations which allow a maximum of 15 ppm of sulfur content in diesel and gasoline (MMA, 2014); however, nitrate and ammonium concentrations were higher. This is due to higher emissions of NO X and ammonia, which are the precursors of these ions, and meteorological conditions that favored formation of ammonium nitrate (Toro et al, 2013). Other ions, which are the sum of chloride and potassium, only accounted for 1.5 ± 1.1% of PM 2.5 mass.…”

Section: Water Soluble Inorganic Ionsmentioning

confidence: 98%

Chemical speciation and source apportionment of fine particulate matter in Santiago, Chile, 2013

Villalobos

Barraza

Jorquera

et al. 2015

Science of The Total Environment

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Urban Atmospheric Ammonia in Santiago City, Chile

Cited by 22 publications

References 25 publications

The importance of vehicle emissions as a source of atmospheric ammonia in the megacity of Shanghai

The importance of vehicle emissions as a source of atmospheric ammonia in the megacity of Shanghai

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

Chemical speciation and source apportionment of fine particulate matter in Santiago, Chile, 2013

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