scholarly journals Black carbon emission and transport mechanisms to the free troposphere at the La Paz/El Alto (Bolivia) metropolitan area based on the Day of Census (2012)

2018 ◽  
Vol 194 ◽  
pp. 158-169 ◽  
Author(s):  
A. Wiedensohler ◽  
M. Andrade ◽  
K. Weinhold ◽  
T. Müller ◽  
W. Birmili ◽  
...  
Keyword(s):  
Black Carbon ◽  
Metropolitan Area ◽  
Carbon Emission ◽  
Free Troposphere ◽  
Transport Mechanisms ◽  
La Paz ◽  
El Alto

scholarly journals Exposure and Respiratory Tract Deposition Dose of Equivalent Black Carbon in High Altitudes

Atmosphere ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 598
Author(s):  
Leizel Madueño ◽  
Simonas Kecorius ◽  
Marcos Andrade ◽  
Alfred Wiedensohler
Keyword(s):  
Black Carbon ◽  
Sea Level ◽  
Minute Ventilation ◽  
Personal Exposure ◽  
Total Daily Dose ◽  
High Altitudes ◽  
La Paz ◽  
Pollution Levels ◽  
El Alto ◽  
High Pollution

The traffic microenvironment accounts for a significant fraction of the total daily dose of inhaled air pollutants. The adverse effects of air pollution may be intensified in high altitudes (HA) due to increased minute ventilation (MV), which may result in higher deposition doses compared to that at sea level. Despite this, air quality studies in regions with combined high pollution levels and enhanced inhalation are limited. The main goals of this study are to investigate how the choice of travel mode (walking, microbus, and cable car ride) determines (i) the personal exposure to equivalent black carbon (eBC) and (ii) the corresponding potential respiratory deposited dose (RDD) in HA. For this investigation, we chose La Paz and El Alto in Bolivia as HA representative cities. The highest eBC exposure occurred in microbus commutes (13 μg m−3), while the highest RDD per trip was recorded while walking (6.3 μg) due to increased MV. On the other hand, the lowest eBC exposure and RDD were observed in cable car commute. Compared with similar studies done at sea level, our results revealed that a HA city should reduce exposure by 1.4 to 1.8-fold to achieve similar RDD at sea level, implying that HA cities require doubly aggressive and stringent road emission policies compared to those at sea level.

Changing markets – Medicinal plants in the markets of La Paz and El Alto, Bolivia

2016 ◽  
Vol 193 ◽  
pp. 76-95 ◽  
Author(s):  
Rainer W. Bussmann ◽  
Narel Y. Paniagua Zambrana ◽  
Laura Araseli Moya Huanca ◽  
Robbie Hart
Keyword(s):  
Medicinal Plants ◽  
La Paz ◽  
El Alto

Tensions between tiers of Bolivian government may grow

2021 ◽  
Keyword(s):  
National Level ◽  
Far Right ◽  
La Paz ◽  
Gubernatorial Elections ◽  
Content Type ◽  
Modus Vivendi ◽  
El Alto ◽  
The Government

Significance The MAS’s national-level appeal tends not to translate into support in localised elections, and a poor choice of candidates, particularly in El Alto, has proved self-defeating. Impacts Second-round gubernatorial elections will probably take place in six out of nine departments. Camacho, a far-right businessman turned politician, will use his newly gained legitimacy to harry the government. The Arce government will seek a modus vivendi with opposition mayors such as those of La Paz and Cochabamba.

scholarly journals The importance of Asia as a source of black carbon to the European Arctic during springtime 2013

2015 ◽  
Vol 15 (20) ◽  
pp. 11537-11555 ◽  
Author(s):  
D. Liu ◽  
B. Quennehen ◽  
E. Darbyshire ◽  
J. D. Allan ◽  
P. I. Williams ◽  
...  
Keyword(s):  
Black Carbon ◽  
Arctic Sea Ice ◽  
Anthropogenic Sources ◽  
The Arctic ◽  
Geometric Standard Deviation ◽  
Free Troposphere ◽  
Aerosol Composition ◽  
Upper Troposphere ◽  
European Arctic ◽  
Mean Concentration

Abstract. Black carbon aerosol (BC) deposited to the Arctic sea ice or present in the free troposphere can significantly affect the Earth's radiation budget at high latitudes yet the BC burden in these regions and the regional source contributions are poorly constrained. Aircraft measurements of aerosol composition in the European Arctic were conducted during the Aerosol–Cloud Coupling And Climate Interactions in the Arctic (ACCACIA) campaign in March 2013. Pollutant plumes were encountered throughout the lower to upper Arctic troposphere featuring enhancements in CO and aerosol mass loadings, which were chemically speciated into BC and non-refractory sulphate and organic matter. FLEXPART-WRF simulations have been performed to evaluate the likely contribution to the pollutants from regional ground sources. By combining up-to-date anthropogenic and open fire biomass burning (OBB) inventories, we have been able to compare the contributions made to the observed pollution layers from the sources of eastern/northern Asia (AS), Europe (EU) and North America (NA). Over 90 % of the contribution to the BC was shown to arise from non-OBB anthropogenic sources. AS sources were found to be the major contributor to the BC burden, increasing background BC loadings by a factor of 3–5 to 100.8 ± 48.4 ng sm−3 (in standard air m3 at 273.15 K and 1013.25 mbar) and 55.8 ± 22.4 ng sm−3 in the middle and upper troposphere respectively. AS plumes close to the tropopause (about 7.5–8 km) were also observed, with BC concentrations ranging from 55 to 73 ng sm−3, which will potentially have a significant radiative impact. EU sources influenced the middle troposphere with a BC mean concentration of 70.8 ± 39.1 ng sm−3 but made a minor contribution to the upper troposphere due to the relatively high latitude of the source region. The contribution of NA was shown to be much lower at all altitudes with BC mean concentration of 20 ng sm−3. The BC transported to the Arctic is mixed with a non-BC volume fraction representing between 90–95 % of the mass, and has a relatively uniform core size distribution with mass median diameter 190–210 nm and geometric standard deviation σg = 1.55–1.65 and this varied little across all source regions. It is estimated that 60–95 % of BC is scavenged between emission and receptor based on BC / ΔCO comparisons between source inventories and measurement. We show that during the springtime of 2013, the anthropogenic pollution particularly from sources in Asia, contributed significantly to BC across the European Arctic free troposphere. In contrast to previous studies, the contribution from open wildfires was minimal. Given that Asian pollution is likely to continue to rise over the coming years, it is likely that the radiative forcing in the Arctic will also continue to increase.

Mountain-valley circulation in central Chile: consequences for Black Carbon deposition over glaciers in wintertime and summertime

2021 ◽  
Author(s):  
Rémy Lapere ◽  
Sylvain Mailler ◽  
Laurent Menut ◽  
Nicolás Huneeus
Keyword(s):  
Black Carbon ◽  
Metropolitan Area ◽  
Dry Deposition ◽  
Regional Scale ◽  
Central Andes ◽  
Urban Air ◽  
Air Masses ◽  
Time Dynamics ◽  
Mountain Valley ◽  
Stable Conditions

<p>The configuration of the Santiago basin, Chile (33.5°S 70.65°W) is quite unique in that it combines very strong emissions of urban anthropogenic pollutants with the steep topography of the coastal and Andes cordilleras surrounding the Metropolitan area. Interactions between atmospheric pollution and mountain meteorology are therefore exacerbated, and the potential for black carbon (BC) deposition on glaciers is strong. Based on chemistry-transport modeling with WRF-CHIMERE, we investigate (i) the pathways leading to deposition of BC from Santiago up to Andean glaciers in wintertime and (ii) the differences in magnitude and time dynamics of such deposition between wintertime and summertime.</p><p>Ice and snow in the central Andes contain significant amounts of BC often attributed to emissions from Santiago. However, given the usually stable conditions in wintertime and the height of the obstacle to overcome for urban air masses (Santiago is 500 m a.s.l., summits are above 4000 m a.s.l.) the pathways for such deposition are not straightforward. We find that, for a typical winter month, up to 40% of BC dry deposition on snow- or ice-covered areas in the central Andes directly downwind from the Metropolitan area can indeed be attributed to emissions from Santiago. The adjacent network of canyons plays a key role in this export: for the case of the Maipo canyon, polluted urban air masses follow gentle slopes upward in the afternoon, consistently with mountain-valley circulation, before being vertically exported when reaching the tip of the main canyon. Statistical analysis shows that zonal wind speed in the urban area and vertical diffusion deep into the canyon account for most of the variance in BC deposition.</p><p>In summertime, more intense convection takes place, and mountain-valley circulation is seldom perturbed by cloud cover, resulting in a greater export potential. Accordingly, summertime dry deposition of BC on glaciers occurs on a regular basis with equivalent amounts each day, contrarily to a more chaotic time series in wintertime. The contribution of wet deposition in winter (nonexistent in summer) exacerbates this irregularity. However, as a consequence of weaker emissions, average monthly dry deposition of BC over the central Andes glaciers (29°S to 38°S) is found to be less than half in summertime (135 µg/m<sup>2</sup>) compared to wintertime (320 µg/m<sup>2</sup>). Given the lesser role played by wood burning for residential heating in summertime, emissions from Santiago through traffic and industry dominate the signal leading to 55% of dry deposition, while it accounts for only 14% in wintertime, at the regional scale, due to more scattered sources.</p>

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