scholarly journals Seasonality in the Δ<sup>33</sup>S measured in urban aerosols highlights an additional oxidation pathway for atmospheric SO<sub>2</sub>

2018 ◽  
Author(s):  
David Au Yang ◽  
Pierre Cartigny ◽  
Karine Desboeufs ◽  
David Wîdory
Keyword(s):  
Seasonal Variations ◽  
Sulfur Isotope ◽  
Monitoring Station ◽  
Urban Aerosols ◽  
Oxidation Pathway ◽  
Local Emissions ◽  
Year 2013 ◽  
Monitoring Stations

Abstract. Sulfates present in urban aerosols collected worldwide usually exhibit significant non-zero Δ33S signatures (from −0.6 to 0.5 ‰) whose origin still remains unclear. To better address this issue, we recorded the seasonal variations of the multiple sulfur isotope compositions of PM10 aerosols collected over the year 2013 at five stations within the Montreal Island (Canada), each characterized by distinct types and levels of pollution. The δ34S-values (n = 155) vary from 2.0 to 11.3 ‰ (± 0.2 ‰, 2σ), the Δ33S-values from −0.080 to 0.341 ‰ (± 0.01 ‰, 2σ) and the Δ36S-values from −1.082 to 1.751 ‰ (± 0.2 ‰, 2σ). Our study evidences a seasonality for both the δ34S and Δ33S, which can be observed either when considering all monitoring stations or, to a lesser degree, when considering them individually. Among them, the monitoring station located at the most western end of the island, upstream of local emissions, yields the lowest mean δ34S coupled to the highest mean Δ33S-values. The Δ33S-values are higher during both summer and winter, and are

scholarly journals Seasonality in the Δ<sup>33</sup>S measured in urban aerosols highlights an additional oxidation pathway for atmospheric SO<sub>2</sub>

2019 ◽  
Vol 19 (6) ◽  
pp. 3779-3796 ◽  
Author(s):  
David Au Yang ◽  
Pierre Cartigny ◽  
Karine Desboeufs ◽  
David Widory
Keyword(s):  
Seasonal Variations ◽  
Sulfur Isotope ◽  
Mineral Dust ◽  
Monitoring Station ◽  
Urban Aerosols ◽  
Oxidation Pathway ◽  
The City ◽  
Local Emissions ◽  
Year 2013 ◽  
Monitoring Stations

Abstract. Sulfates present in urban aerosols collected worldwide usually exhibit significant non-zero Δ33S signatures (from −0.6 ‰ to 0.5 ‰) whose origin still remains unclear. To better address this issue, we recorded the seasonal variations of the multiple sulfur isotope compositions of PM10 aerosols collected over the year 2013 at five stations within the Montreal Island (Canada), each characterized by distinct types and levels of pollution. The δ34S-values (n= 155) vary from 2.0 ‰ to 11.3 ‰ (±0.2 ‰, 2σ), the Δ33S-values from −0.080 ‰ to 0.341 ‰ (±0.01 ‰, 2σ) and the Δ36S-values from −1.082 ‰ to 1.751 ‰ (±0.2 ‰, 2σ). Our study evidences a seasonality for both the δ34S and Δ33S, which can be observed either when considering all monitoring stations or, to a lesser degree, when considering them individually. Among them, the monitoring station located at the most western end of the island, upstream of local emissions, yields the lowest mean δ34S coupled to the highest mean Δ33S-values. The Δ33S-values are higher during both summer and winter, and are < 0.1 ‰ during both spring and autumn. As these higher Δ33S-values are measured in “upstream” aerosols, we conclude that the mechanism responsible for these highly positive S-MIF also occurs outside and not within the city, at odds with common assumptions. While the origin of such variability in the Δ33S-values of urban aerosols (i.e. −0.6 ‰ to 0.5 ‰) is still subject to debate, we suggest that oxidation by Criegee radicals and/or photooxidation of atmospheric SO2 in the presence of mineral dust may play a role in generating such large ranges of S-MIF.

Seasonal variations of elemental carbon in urban aerosols as measured by two common thermal-optical carbon methods

2009 ◽  
Vol 407 (18) ◽  
pp. 5176-5183 ◽  
Author(s):  
Min-Suk Bae ◽  
James J. Schauer ◽  
Jay R. Turner ◽  
Philip K. Hopke
Keyword(s):  
Seasonal Variations ◽  
Elemental Carbon ◽  
Urban Aerosols

scholarly journals Radiocarbon in the Air of Central Europe: Long-Term Investigations

Radiocarbon ◽  
2010 ◽  
Vol 52 (2) ◽  
pp. 823-834 ◽  
Author(s):  
I Svetlik ◽  
P P Povinec ◽  
M Molnár ◽  
M Vána ◽  
A Šivo ◽  
...  
Keyword(s):  
Central Europe ◽  
Monitoring Station ◽  
High Mountain ◽  
The Czech Republic ◽  
Suess Effect ◽  
Clean Air ◽  
Low Altitude ◽  
The Impact ◽  
Monitoring Stations

Regional levels of radiocarbon have been monitored in order to investigate the impact of fossil fuel combustion on the activity of atmospheric 14CO2 in central Europe. Data from atmospheric 14CO2 monitoring stations in the Czech Republic, Slovakia, and Hungary for the period 2000–2008 are presented and discussed. The Prague and Bratislava monitoring stations showed a distinct local Suess effect when compared to the Jungfraujoch clean-air monitoring station. However, during the summer period, statistically insignificant differences were observed between the low-altitude stations and the high-mountain Jungfraujoch station. 14C data from the Hungarian monitoring locality at Dunaföldvár and the Czech monitoring station at Košetice, which are not strongly affected by local fossil CO2 sources, indicate similar grouping and amplitudes, typical for a regional Suess effect.

scholarly journals Identification of spikes associated with local sources in continuous time series of atmospheric CO, CO<sub>2</sub> and CH<sub>4</sub>

2017 ◽  
Author(s):  
Abdelhadi El Yazidi ◽  
Michel Ramonet ◽  
Philippe Ciais ◽  
Gregoire Broquet ◽  
Isabelle Pison ◽  
...  
Keyword(s):  
Time Series ◽  
Detection Methods ◽  
Local Source ◽  
Observation System ◽  
High Mountain ◽  
Spike Detection ◽  
Automatic Data ◽  
Background Site ◽  
Local Emissions ◽  
Monitoring Stations

Abstract. This study deals with the problem of identifying atmospheric data that are influenced by local emissions which cause spikes in time series of greenhouse gases and long-lived tracer measurements. We considered three spike detection methods known as coefficient of variation (COV), robust extraction of baseline signal (REBS), and standard deviation of the background (SD), to detect and filter positive spikes in continuous greenhouse gas time series from four monitoring stations representative of the ICOS (Integrated Carbon Observation System) European Infrastructure network. The results of the different methods are compared to each other and against a manual detection performed by station managers. Four stations were selected as test cases to apply the spike detection methods: a continental rural tower of 100 m height in Eastern France (OPE); a high mountain observatory in the south-west of France (PDM); a regional marine background site in Crete (FKL); and a marine clean-air background site in the southern hemisphere in Amsterdam island (AMS). This panel allows addressing the spike detection problems in time series with different variability. Two years of continuous measurements of CO2, CH4 and CO were analyzed. All the methods were found to be able to detect short-term spikes (lasting from a few seconds to few minutes) in the time series. Analysis of the results of each method leads us to exclude the use of the COV method because of its requirement to arbitrarily specify an a priori percentage of rejected data in the time series, which may over- or under-estimate the actual number of spikes. The two other methods freely determine the number of spikes for a given set of parameters, and the values of these parameters were calibrated to provide the best match with spikes known to reflect local emissions episodes well documented by the station managers. More than 96 % of the spikes manually identified by station managers were successfully detected both in the SD and the REBS methods after the best adjustment of parameter values. At PDM, measurements made by two analyzers 200 m from each other allow to confirm that the CH4 spikes identified in one of the time-series but not in the other correspond to a local source from a sewage treatment facility in one of the observatory buildings. From this experiment, we found that the REBS method underestimates the number of positive anomalies in the CH4 data caused by local sewage emissions. As a conclusion, we recommend the use of the SD method, which also appears as the easiest one to implement as automatic data processing, for the operational filtering of spikes in greenhouses gases time series at global and regional monitoring stations of networks like ICOS.

scholarly journals Preliminary results of land subsidence monitoring in the Ca Mau Province

2020 ◽  
Vol 382 ◽  
pp. 111-115
Author(s):  
Kjell Karlsrud ◽  
Lloyd Tunbridge ◽  
Nguyen Quoc Khanh ◽  
Nguyen Quoc Dinh
Keyword(s):  
Water Level ◽  
Sea Level ◽  
Seasonal Variations ◽  
Monitoring Program ◽  
Ho Chi Minh City ◽  
Groundwater Pumping ◽  
Present Rate ◽  
Subsidence Monitoring ◽  
First Time ◽  
Monitoring Stations

Abstract. A previous study of the Ca Mau province in Vietnam (Karlsrud et al., 2017a) suggested that ongoing groundwater pumping, which by 2012 had caused a drawdown of the water level in aquifers of up to 20 m, caused subsidence of the order 2–4 cm yr−1, and could have reached over 40 cm already. Earlier InSAR studies also suggested ongoing subsidence rates of that order. If the groundwater pumping continues, the total subsidence could reach well over 1 m within the next few decades. The predicted climate driven sea level rise, to be of the order of 60 cm by 2100, will further add to the severe effect of the subsidence. As most of the Ca Mau province lies only 0.5 to 1.5 m a.s.l. (above sea level), the consequences would rapidly become very serious for the livelihood of people in the region. Increased saltwater intrusion into canals and tributaries in the province, and beginning salination of some of the aquifers from which groundwater is pumped, is already observed. In 2017, for the first time, a physical system for subsidence monitoring was installed at three selected locations in the Ca Mau province. At each location a deep benchmark to a depth of 100 m was installed, each with 3 piezometers at depths ranging from 15 to 60 m. An InSAR corner reflector was also installed at each site. The paper presents data collected from these new monitoring stations up until the middle 2019. When including estimated subsidence stemming from the soil levels deeper than 100 m, the total present rate of subsidence at the three new monitoring stations range from 17 to 44 mm yr−1. New and previous data show an almost linear decrease in water level within the aquifers from which groundwater is pumped. The data show some seasonal variations in subsidence rates, which is also reflected in variations in pore pressures in the sediments. Such variations are probably related to seasonal variations in levels of groundwater pumping. It is feared that many of the other provinces south of Ho Chi Minh city, face similar subsidence problems. The monitoring program should be extended to verify that. Measures to reduce groundwater and subsidence are urgently needed.

scholarly journals Air Quality Measurements in Kitchener, Ontario, Canada Using Multisensor Mini Monitoring Stations

Atmosphere ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 83
Author(s):  
Wisam Mohammed ◽  
Nicole Shantz ◽  
Lucas Neil ◽  
Tom Townend ◽  
Adrian Adamescu ◽  
...  
Keyword(s):  
Air Quality ◽  
Quality Monitoring ◽  
Monitoring Station ◽  
Air Quality Monitoring ◽  
Long Distance ◽  
Air Quality Measurements ◽  
Custom Made ◽  
The Impact ◽  
Quality Measurements ◽  
Monitoring Stations

The Region of Waterloo is the third fastest growing region in Southern Ontario in Canada with a population of 619,000 as of 2019. However, only one air quality monitoring station, located in a city park in Kitchener, Ontario, is currently being used to assess the air quality of the region. In September 2020, a network of AQMesh Multisensor Mini Monitoring Stations (pods) were installed near elementary schools in Kitchener located near different types of emission source. Data analysis using a custom-made long-distance scaling software showed that the levels of nitrogen oxides (NO and NO2), ground level ozone (O3), and fine particulate matter (PM2.5) were traffic related. These pollutants were used to calculate the Air Quality Health Index-Plus (AQHI+) at each location, highlighting the inability of the provincial air quality monitoring station to detect hotspot areas in the city. The case study presented here quantified the impact of the 2021 summer wildfires on the local air quality at a high time resolution (15-min). The findings in this article show that these multisensor pods are a viable alternative to expensive research-grade equipment. The results highlight the need for networks of local scale air quality measurements, particularly in fast-growing cities in Canada.

scholarly journals Air quality and acid deposition impacts of local emissions and transboundary air pollution in Japan and South Korea

2019 ◽  
Vol 19 (20) ◽  
pp. 13309-13323 ◽  
Author(s):  
Steve Hung Lam Yim ◽  
Yefu Gu ◽  
Matthew A. Shapiro ◽  
Brent Stephens
Keyword(s):  
Air Pollution ◽  
Air Quality ◽  
South Korea ◽  
East Asia ◽  
Human Health ◽  
Acid Deposition ◽  
Seasonal Variations ◽  
Ambient Air ◽  
Transboundary Air Pollution ◽  
Local Emissions

Abstract. Numerous studies have reported that ambient air pollution, which has both local and long-range sources, causes adverse impacts on the environment and human health. Previous studies have investigated the impacts of transboundary air pollution (TAP) in East Asia, albeit primarily through analyses of episodic events. In addition, it is useful to better understand the spatiotemporal variations in TAP and the resultant impact on the environment and human health. This study aimed at assessing and quantifying the air quality impacts in Japan and South Korea due to local emissions and TAP from sources in East Asia - one of the most polluted regions in the world. We applied state-of-the-science atmospheric models to simulate air quality in East Asia and then analyzed the air quality and acid deposition impacts of both local emissions and TAP sources in Japan and South Korea. Our results show that ∼ 30 % of the annual average ambient PM2.5 concentrations in Japan and South Korea in 2010 were contributed to by local emissions within each country, while the remaining ∼ 70 % were contributed to by TAP from other countries in the region. More detailed analyses also revealed that the local contribution was higher in the metropolises of Japan (∼ 40 %–79 %) and South Korea (∼ 31 %–55 %) and that minimal seasonal variations in surface PM2.5 occurred in Japan, whereas there was a relatively large variation in South Korea in the winter. Further, among all five studied anthropogenic emission sectors of China, the industrial sector represented the greatest contributor to annual surface PM2.5 concentrations in Japan and South Korea, followed by the residential and power generation sectors. Results also show that TAP's impact on acid deposition (SO42- and NO3-) was larger than TAP's impact on PM2.5 concentrations (accounting for over 80 % of the total deposition), and that seasonal variations in acid deposition were similar for both Japan and South Korea (i.e., higher in both the winter and summer). Finally, wet deposition had a greater impact on mixed forests in Japan and savannas in South Korea. Given these significant impacts of TAP in the region, it is paramount that cross-national efforts should be taken to mitigate air pollution problems across East Asia.

scholarly journals Sulfur isotope analyses of individual aerosol particles in the urban aerosol at a central European site (Mainz, Germany)

2008 ◽  
Vol 8 (23) ◽  
pp. 7217-7238 ◽  
Author(s):  
B. W. Sinha ◽  
P. Hoppe ◽  
J. Huth ◽  
S. Foley ◽  
M. O. Andreae
Keyword(s):  
Isotopic Composition ◽  
Gas Phase ◽  
Isotope Fractionation ◽  
Sulfur Isotope ◽  
Aerosol Particles ◽  
Isotopic Signature ◽  
Oxidation Pathway ◽  
Different Types ◽  
Gas Phase Oxidation ◽  
The Individual

Abstract. Sulfur isotope analysis of atmospheric aerosols is a well established tool for identifying sources of sulfur in the atmosphere, estimating emission factors, and tracing the spread of sulfur from anthropogenic sources through ecosystems. Conventional gas mass spectrometry averages the isotopic compositions of several different types of sulfur aerosol particles, and therefore masks the individual isotopic signatures. In contrast, the new single particle technique presented here determines the isotopic signature of the individual particles. Primary aerosol particles retain the original isotopic signature of their source. The isotopic composition of secondary sulfates depends on the isotopic composition of precursor SO2 and the oxidation process. The fractionation with respect to the source SO2 is poorly characterized. In the absence of conclusive laboratory experiments, we consider the kinetic fractionation of −9‰ during the gas phase oxidation of SO2 by OH as suggested by Saltzman et al. (1983) and Tanaka et al. (1994) to be the most reasonable estimate for the isotope fractionation during gas phase oxidation of SO2 (αhom=0.991) and the equilibrium fractionation for the uptake of SO2 (g) into the aqueous phase and the dissociation to HSO3- of +16.5‰ measured by Eriksen (1972a) to be the best approximation for the fractionation during oxidation in the aqueous phase (αhet=1.0165). The sulfur isotope ratio of secondary sulfate particles can therefore be used to identify the oxidation pathway by which this sulfate was formed. However, the fraction of heterogeneous and homogeneous oxidation pathway calculated is very sensitive to the isotope fractionation assumed for both pathways. With the new single particle technique, different types of primary and secondary sulfates were first identified based on their chemical composition, and then their individual isotopic signature was measured separately. Our samples were collected in Mainz, Germany, in an urban environment. Secondary sulfates (ammonium sulfate, gypsum, mixed sulfates) and coatings on silicates or organic aerosol dominated sulfate loadings in our samples. Comparison of the chemical and isotopic composition of secondary sulfates showed that the isotopic composition was homogeneous, independent of the chemical composition. This is typical for particles that derive from in-cloud processing. The isotopic composition of the source SO2 of secondary sulfates was calculated based on the isotopic composition of particles with known oxidation pathway and showed a strong dependence on wind direction. The contribution of heterogeneous oxidation to the formation of secondary sulfate was highly variable (35%–75%) on day-to-day basis and depended on meteorological conditions.

Development of on-site fish exposure system placed in water quality monitoring stations along a river

2005 ◽  
Vol 52 (12) ◽  
pp. 275-282 ◽  
Author(s):  
T. Higashitani ◽  
K. Miyajima ◽  
N. Nakada ◽  
M. Yasojima ◽  
H. Tanaka ◽  
...  
Keyword(s):  
Water Quality ◽  
River Water ◽  
Estrogenic Activity ◽  
Sewage Treatment ◽  
Water Quality Monitoring ◽  
Quality Monitoring ◽  
Monitoring Station ◽  
Exposure System ◽  
Fish Exposure ◽  
Monitoring Stations

Estrogen-like substances have been suspected to cause feminization of wild fish in rivers in Japan. To elucidate the influence of estrogen-like substances on fish in river, we have started to develop the on-site continuous fish exposure system using medaka Oryzias latipes that were placed in water quality monitoring stations along a river. Adult male medaka were exposed to the river water in a glass exposure tank placed in the monitoring stations. Flow rate of water and water temperature were controlled at 30L/hour and 26°C respectively, and a light: dark cycle was maintained 16:8 hours. A commercial diet free from phyto-estrogens was fed 4 times in a day using automatic feeder. After 2-week exposure, hepatic vitellogenin concentration of each male medaka was measured. The exposure tests were repeatedly performed at both the upstream and the downstream of sewage treatment plants along the River Tama which is a representative urbanized river in Japan. At the control site Haijimabashi monitoring station, vitellogenin was not detected in male medaka. On the other hand, at the Ishihara monitoring station which is the most downstream in this test area, every male medaka were produced vitellogenin in the test performed in the spring of 2004. As the results of the water quality analysis, it could be inferred that the estrone derived from effluents of sewage treatment plants caused the feminization of male medaka. The reason why the concentrations of the estrone and the estrogenic activity using DNA recombinant yeast varied in proportion to the electric conductivity of river water measured at the water quality monitoring station. Furthermore, after continuous 2-week exposure, the vitellogenin production of male medaka was reduced similar to the decrease of the concentrations of the estrone and the estrogenic activity of river water.

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