Tracking Airborne Pollution with Environmental Magnetism in A Medium-Sized African City

As in other parts of the world, air pollution over West and Central Africa has major health and meteorological impacts. Air quality assessment and its possible sanitary impact have become essential even in medium-sized towns, therefore amplifying the need for easy-to-implement monitoring methods with low environmental impact. We present here the potential of magnetic methods to monitor air quality at street level in the medium-sized city of Maroua (northern Cameroon) affected by dust-laden desert winds. More than five hundred (544) samples of bark and leaves taken from Neem trees in Maroua were analyzed. Magnetic susceptibility, saturation remanence, and S-ratio were found to determine the concentration and nature of magnetic particles. They are dominated by magnetite-like particle signals as a part of particulate emissions due to urban activities, including both traffic, composed of a substantial proportion of motorcycles, and wood burning for food preparation. We show that both bark and leaves from Neem trees are adequate passive bio-recorders. The use of both enables different times and heights to be sampled, allowing for the high-resolution monitoring, in terms of spatialization, of various urban environments. Particle emissions require assessment and screening that could be carried out rapidly and efficiently by magnetic methods on bio-recorders, even in cities impacted by dust-laden wind.

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U/pb dating of precambrian rocks from northern cameroon, orogenic evolution and chronology of the pan-african belt of central africa

Precambrian Research ◽

10.1016/0301-9268(87)90040-4 ◽

1987 ◽

Vol 37 (1) ◽

pp. 71-87 ◽

Cited By ~ 83

Author(s):

S.F. Toteu ◽

A. Michard ◽

J.M. Bertrand ◽

G. Rocci

Keyword(s):

Central Africa ◽

Precambrian Rocks ◽

Pan African ◽

Northern Cameroon

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To what extent does the environmental magnetism technique acts as a way of assessing the uptake of atmospheric particles by plants?

10.5194/egusphere-egu21-8263 ◽

2021 ◽

Author(s):

Sarah Letaïef ◽

Pierre Camps ◽

Thierry Poidras ◽

Patrick Nicol ◽

Delphine Bosch ◽

...

Keyword(s):

Air Quality ◽

Endemic Species ◽

Fine Particles ◽

Magnetic Measurements ◽

Deposition Velocity ◽

Environmental Magnetism ◽

Air Pollutant ◽

Atmospheric Pollutants ◽

Area Index ◽

The Impact

Numerous studies have already shown the possibility of tracing the sources, the compositions, and the concentration of atmospheric pollutants deposited on plant leaves. In environmental geochemistry, inter-element and isotope ratios from chemical element assays have been used for these purposes. Alternatively, environmental magnetism represents a quick and inexpensive asset that is increasingly used as a relative indicator for concentrations of air pollutant on bio accumulator surfaces such as plants. However, a fundamental issue is still pending: Do plants in urban areas represent a sink for fine particles that is sufficiently effective to improve air quality? This is a very topical issue because some studies have shown that the foliage can trap fine particles by different dry deposition processes, while other studies based on CFD models indicate that plant hedges in cities can hinder the atmospheric dispersion of pollutants and therefore increase pollution at the level of emission sources such as traffic. To date, no consensus was made because several factors not necessary well known must be taken into account, such as, PM concentration and size, prevailing wind, surface structures, epicuticular wax, to mention just a few examples. A first step toward the understanding of the impact of urban greens on air quality is the precise determination of the deposition velocity (Vd) parameter. This latter is specific for each species and it is most of the time underestimated in modeling-based studies by taking standard values. In that perspective, we built a wind tunnel (6 m long, 86 cm wide and 86 cm high) to perform analogical experiments on different endemic species. All parameters are controlled, i.e, the wind speed, the nature and the injection time of pollutants (Gasoline or Diesel exhausts, brakes or tires dust, etc&#8230;). We can provide the PM concentrations upwind and downwind of natural reconstituted hedges by two dustmeters (LOACs - M&#233;t&#233;oModem). Beforehand, parameters such as the hedge resistance (%) or the leaf area index (LAI) have been estimated for each studied specie to allow comparability between plants removal potential. The interest would ultimately combine PM concentration measured by size bins from the LOACs with magnetic measurements (ARM, IRM100mT, IRM300mT and SIRM) of plant leaves. The idea is to check whether it would be possible to precisely determine in situ the dust removal rate by urban greens with environmental magnetism measurements. Up to now, we have carried out on different endemic species such as Elaeagnus x ebbingei leaves and Mediterranean pine needles, the results of which will be presented.

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Impact of Urban Land Use and Anthropogenic Heat on Air Quality in Urban Environments

Springer Proceedings in Complexity - Air Pollution Modeling and its Application XXVI ◽

10.1007/978-3-030-22055-6_24 ◽

2019 ◽

pp. 153-158 ◽

Cited By ~ 1

Author(s):

Shuzhan Ren ◽

Craig Stroud ◽

Stephane Belair ◽

Sylvie Leroyer ◽

Michael Moran ◽

...

Keyword(s):

Land Use ◽

Air Quality ◽

Urban Land ◽

Urban Environments ◽

Urban Land Use ◽

Anthropogenic Heat

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Comparison of primary and secondary particle formation from natural gas engine exhaust and of their volatility characteristics

Atmospheric Chemistry and Physics ◽

10.5194/acp-17-8739-2017 ◽

2017 ◽

Vol 17 (14) ◽

pp. 8739-8755 ◽

Cited By ~ 6

Author(s):

Jenni Alanen ◽

Pauli Simonen ◽

Sanna Saarikoski ◽

Hilkka Timonen ◽

Oskari Kangasniemi ◽

...

Keyword(s):

Air Quality ◽

Natural Gas ◽

Particulate Emissions ◽

Engine Exhaust ◽

Gas Engine ◽

Secondary Aerosol ◽

Formation Potential ◽

Natural Gas Engine ◽

Evaporation Temperature ◽

Catalyst Temperature

Abstract. Natural gas usage in the traffic and energy production sectors is a growing trend worldwide; thus, an assessment of its effects on air quality, human health and climate is required. Engine exhaust is a source of primary particulate emissions and secondary aerosol precursors, which both contribute to air quality and can cause adverse health effects. Technologies, such as cleaner engines or fuels, that produce less primary and secondary aerosols could potentially significantly decrease atmospheric particle concentrations and their adverse effects. In this study, we used a potential aerosol mass (PAM) chamber to investigate the secondary aerosol formation potential of natural gas engine exhaust. The PAM chamber was used with a constant UV-light voltage, which resulted in relatively long equivalent atmospheric ages of 11 days at most. The studied retro-fitted natural gas engine exhaust was observed to form secondary aerosol. The mass of the total aged particles, i.e., particle mass measured downstream of the PAM chamber, was 6–268 times as high as the mass of the emitted primary exhaust particles. The secondary organic aerosol (SOA) formation potential was measured to be 9–20 mg kgfuel−1. The total aged particles mainly consisted of organic matter, nitrate, sulfate and ammonium, with the fractions depending on exhaust after-treatment and the engine parameters used. Also, the volatility, composition and concentration of the total aged particles were found to depend on the engine operating mode, catalyst temperature and catalyst type. For example, a high catalyst temperature promoted the formation of sulfate particles, whereas a low catalyst temperature promoted nitrate formation. However, in particular, the concentration of nitrate needed a long time to stabilize – more than half an hour – which complicated the conclusions but also indicates the sensitivity of nitrate measurements on experimental parameters such as emission source and system temperatures. Sulfate was measured to have the highest evaporation temperature, and nitrate had the lowest. The evaporation temperature of ammonium depended on the fractions of nitrate and sulfate in the particles. The average volatility of the total aged particles was measured to be lower than that of primary particles, indicating better stability of the aged natural gas engine-emitted aerosol in the atmosphere. According to the results of this study, the exhaust of a natural gas engine equipped with a catalyst forms secondary aerosol when the atmospheric ages in a PAM chamber are several days long. The secondary aerosol matter has different physical characteristics from those of primary particulate emissions.

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PARAMETERS OF INTEREST FOR THE DESIGN OF GREEN INFRASTRUCTURE

Journal of Urban and Environmental Engineering ◽

10.4090/juee.2019.v13n1.092101 ◽

2019 ◽

pp. 92-101

Author(s):

Marija Šperac ◽

Dino Obradović

Keyword(s):

Air Quality ◽

Urban Environment ◽

Air Temperature ◽

Green Infrastructure ◽

Land Surface ◽

Urban Areas ◽

Hydrological Cycle ◽

Urban Environments ◽

Land Surfaces ◽

Selection Of

The urbanization process significantly reduced the permeability of land surfaces, which affected the changes of runoff characteristics and the relations in the hydrological cycle. In urban environments, the relationships within the hydrological cycle have changed in quantity, in particular: precipitation, air temperature, evaporation, and infiltration. By applying the green infrastructure (GI) to urban environments is beneficial for the water resources and the social community. GI has an effect on the improvement of ecological, economic, and social conditions. Using GI into urban areas increases the permeability of land surfaces, whereby decreasing surface runoff, and thus the frequency of urban floods. It also has a significant influence on the regulation of air quality, water purification, climate change impact, and the changes in the appearance of the urban environment. When planning and designing the GI, it is necessary to identify the type of GI and determine the size and location of the selected GI. Since each urban environment has its own characteristics, it is necessary to analyze them before deciding on the GI. The paper analyzed meteorological parameters (precipitation, air temperature, insolation, air humidity) affecting the selection of GI types, using the specific example of an urban environment – the City of Osijek, Croatia. Significant parameters when designing GI are operation and maintenance These parameters directly affect the efficiency of GI. The proper selection of GI and its location results in maximum gains: the reduction of land surface drainage - drainage of the sewage system, purification and retention of precipitation at the place of production, the improvement of air quality, and the improvement of living conditions in urban environments

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Association of polycyclic aromatic hydrocarbons in moss with blood biomarker among nearby residents in Portland, Oregon

10.1101/2021.07.15.21260592 ◽

2021 ◽

Author(s):

Igor Burstyn ◽

Geoffrey H. Donovan ◽

Yvonne L. Michael ◽

Sarah Jovan

Keyword(s):

Polycyclic Aromatic Hydrocarbons ◽

Air Quality ◽

Dna Adducts ◽

Aromatic Hydrocarbons ◽

Human Health Risk ◽

Monitoring Methods ◽

Wood Fire ◽

Individual Determinants ◽

Polycyclic Aromatic ◽

Environmental Air

Polycyclic aromatic hydrocarbons (PAHs) are a component of air pollutants that are costly to measure using traditional air-quality monitoring methods. We used an epiphytic bio-indicator (moss genus: Orthotrichum) to cost-effectively evaluate atmospheric deposition of PAHs in Portland, Oregon in May 2013. However, it is unclear if measurements derived from these bioindicators are good proxies for human exposure. To address this question, we simultaneously, measured PAH-DNA adducts in blood samples of non-smokers residing close to the sites of moss measurements. We accounted for individual determinants of PAH uptake that are not related to environmental air quality through questionnaires, e.g., wood fires, consumption of barbecued and fried meats. Correlation and linear regression (to control for confounders from the lifestyle factors) evaluated the associations. We did not observe evidence of an association between PAH levels in moss and PAH-DNA adducts in blood of nearby residents, but higher level of adduct were evident in those who used wood fire in their houses in the last 48 hours. It remains to be determined whether bio-indicators in moss can be used for human health risk assessment.

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A New Wearable System for Sensing Outdoor Environmental Conditions for Monitoring Hyper-Microclimate

Sensors ◽

10.3390/s22020502 ◽

2022 ◽

Vol 22 (2) ◽

pp. 502

Author(s):

Roberta Jacoby Cureau ◽

Ilaria Pigliautile ◽

Anna Laura Pisello

Keyword(s):

Air Quality ◽

Environmental Monitoring ◽

Smart Cities ◽

Control Unit ◽

Urban Environments ◽

Physical Parameters ◽

Negative Effects ◽

Rapid Urbanization ◽

Wearable System ◽

New Device

The rapid urbanization process brings consequences to urban environments, such poor air quality and the urban heat island issues. Due to these effects, environmental monitoring is gaining attention with the aim of identifying local risks and improving cities’ liveability and resilience. However, these environments are very heterogeneous, and high-spatial-resolution data are needed to identify the intra-urban variations of physical parameters. Recently, wearable sensing techniques have been used to perform microscale monitoring, but they usually focus on one environmental physics domain. This paper presents a new wearable system developed to monitor key multidomain parameters related to the air quality, thermal, and visual domains, on a hyperlocal scale from a pedestrian’s perspective. The system consisted of a set of sensors connected to a control unit settled on a backpack and could be connected via Wi-Fi to any portable equipment. The device was prototyped to guarantee the easy sensors maintenance, and a user-friendly dashboard facilitated a real-time monitoring overview. Several tests were conducted to confirm the reliability of the sensors. The new device will allow comprehensive environmental monitoring and multidomain comfort investigations to be carried out, which can support urban planners to face the negative effects of urbanization and to crowd data sourcing in smart cities.

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Size-resolved particle number emissions in Beijing determined from measured particle size distributions

Atmospheric Chemistry and Physics ◽

10.5194/acp-20-11329-2020 ◽

2020 ◽

Vol 20 (19) ◽

pp. 11329-11348 ◽

Cited By ~ 2

Author(s):

Jenni Kontkanen ◽

Chenjuan Deng ◽

Yueyun Fu ◽

Lubna Dada ◽

Ying Zhou ◽

...

Keyword(s):

Particle Size ◽

Air Quality ◽

Particle Number ◽

Aerosol Particles ◽

Urban Environments ◽

Integrated Assessment Model ◽

Assessment Model ◽

Size Distributions ◽

Particle Size Distributions ◽

Measured Particle

Abstract. The climate and air quality effects of aerosol particles depend on the number and size of the particles. In urban environments, a large fraction of aerosol particles originates from anthropogenic emissions. To evaluate the effects of different pollution sources on air quality, knowledge of size distributions of particle number emissions is needed. Here we introduce a novel method for determining size-resolved particle number emissions, based on measured particle size distributions. We apply our method to data measured in Beijing, China, to determine the number size distribution of emitted particles in a diameter range from 2 to 1000 nm. The observed particle number emissions are dominated by emissions of particles smaller than 30 nm. Our results suggest that traffic is the major source of particle number emissions with the highest emissions observed for particles around 10 nm during rush hours. At sizes below 6 nm, clustering of atmospheric vapors contributes to calculated emissions. The comparison between our calculated emissions and those estimated with an integrated assessment model GAINS (Greenhouse Gas and Air Pollution Interactions and Synergies) shows that our method yields clearly higher particle emissions at sizes below 60 nm, but at sizes above that the two methods agree well. Overall, our method is proven to be a useful tool for gaining new knowledge of the size distributions of particle number emissions in urban environments and for validating emission inventories and models. In the future, the method will be developed by modeling the transport of particles from different sources to obtain more accurate estimates of particle number emissions.

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Multi-proxy study of the Cretaceous-Paleogene (K-Pg) boundary in deep-sea turbiditic sediments in the Uzgruň section (Outer Flysch Carpathians, Czech Republic)

10.5194/egusphere-egu21-2625 ◽

2021 ◽

Author(s):

Šimon Kdýr ◽

Tiiu Elbra ◽

Miroslav Bubík ◽

Petr Schnabl ◽

Lilian Švábenická

Keyword(s):

Magnetic Susceptibility ◽

Czech Republic ◽

Detection Limit ◽

Remanent Magnetization ◽

Magnetic Particles ◽

Principal Component ◽

Natural Remanent Magnetization ◽

Ongoing Research ◽

Small Stream ◽

Magnetic Methods

The composite profile, with 4 studied sections, is located near the Uzgru&#328; village (Czech Republic) next to a small stream. The profile is composed of Late Maastrichtian to Palaeocene flysch sediments and the K-Pg boundary is set in claystones within this turbiditic setting. Ongoing research of local paleoenvironment and stratigraphy is based on paleo- and rock-magnetic methods, micropaleontology and geochemistry to obtain more detailed view of the local situation during the K-Pg extinction event. Based on biostratigraphy, two dinocyst zones (Bub&#237;k et al., 2002): Palynodium grallator and Carpatella cornuta (first occurrence in the Danian), two calcareous nannofossil zones in the Upper Maastrichtian, and the agglutinated foraminifer zone Rzehakina fissistomata in the Paleogene were distinguished. Biostratigraphic data support the K-Pg boundary interval. The uppermost Maastrichtian is indicated by nannofossil species Micula prinsii, UC26dTP zone. Basal Paleogene non-calcareous strata contain dinocyst Carpatella cornuta and agglutinated foraminifers of Rzehakina fissistomata zone. The presence of low-latitude nannofossil taxa M. prinsii and Ceratolithoides kamptneri show input of warm waters during the uppermost Maastrichtian. Several rock-magnetic methods, such as acquisition of Isothermal remanent magnetization (IRM), acquisition of Anhysteretic remanent magnetization (ARM), Anisotropy of magnetic susceptibility (AMS), Field dependence of magnetic susceptibility (HD) and Frequency dependence of magnetic susceptibility (FD), were applied to estimate behaviour and origin of magnetic particles. Natural remanent magnetization (NRM) values of samples range from 0.09 to 2.48 mA/m. Volume normalized magnetic susceptibility (MS) show values from 130 up to 1197 SI*10-6. There is no increase observed in MS across stratigraphic boundary due to turbiditic evolution of sediment. Due to character of sediments, we applied alternating field (AF) demagnetization and used principal component analysis (PCA; Kirschvink, 1980) for estimation of characteristic remanent component. Most of the K/Pg sections worldwide have well documented Iridium anomaly. In Uzgru&#328;, the preliminary results show that although the values are not as pronounced, the Ir at K-Pg boundary is still higher than in surrounding sediments. For tracing of Deccan traps effect we plan to apply mercury (Hg)/total organic carbon (TOC) stratigraphy. TOC content of 20 pilot samples is low, but not under detection limit of the instrumentation (mean value 0.92 wt%). One sample reached value 4.41 wt% of TOC. Sulphur contents are reaching 1 wt%, but several samples were under detection limit of the instrumentation. Sulphur concentrations suggest more reduction conditions of burial.Current research is supported by Czech Science Foundation project no. 19-07516S and is in accordance with research plan no. RVO67985831.Bub&#237;k, M., Adamov&#225;, M., B&#261;k, M., Franc&#367;, J., Gedl, P., Mikul&#225;&#353;, R., &#352;v&#225;benick&#225;, L., & Uchman, A. (2002). V&#253;sledky v&#253;zkumu hranice k&#345;&#237;da/terci&#233;r v magursk&#233;m fly&#353;i u Uzgrun&#283;. Geologick&#233; v&#253;zkumy na Morav&#283; a ve Slezsku, 9, 18&#8211;22L. Kirschvink (1980), The least-squares line and plane and the analysis of palaeomagnetic data,&#160;Geophysical Journal International, 62(3), 699&#8211;718,&#160;https://doi.org/10.1111/j.1365-246X.1980.tb02601.x

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