Carbonaceous aerosols have been sampled weekly in 2002 and 2003 at Pic du Midi (PdMO), an isolated high-altitude Pyrenean station. High concentrations of both black carbon (BC) and total organic ...carbon (OC) have been observed during the exceptional prolonged warm dry spell over western Europe in spring–summer 2003, culminating during the first 2 weeks in August. The aerosol ORISAM-TM4 global model Guillaume, B., Liousse, C., Rosset, R., Cachier, H., Van Velthoven, P., Bessagnet, B., Poisson, N., 2007. ORISAM-TM4: a new global sectional multi-component aerosol model including SOA formation—focus on carbonaceous BC and OC aerosols. Tellus B 59, 283–302., together with new updated European emission inventories, appears apt to closely simulate at this PdMO site the BC and OC aerosol components during the whole 2002–2003 period, including the August 2003 heat wave. Further, ORISAM-TM4 provides unique detailed information on both primary and secondary OC fractions together with differentiated aerosol secondary anthropogenic (SOAA) vs. biogenic OC (SOAB) contributions, not accessible to measurements. Such comparisons have been extended to two other high-altitude European sites of the CARBOSOL programme, Sonnblick (Austrian Alps) and Puy de Dôme (central France). At these two sites, the agreement between simulations and measured values is clearly not so close as at PdMO, with systematic more elevated measured values of both BC and OC, presumably due to local and regional sources.
Air quality degradation is a major issue in the large conurbations on
the shore of the Gulf of Guinea. We present for the first time
PM2.5 time series collected in Cotonou, Benin, and Abidjan,
Côte ...d'Ivoire, from February 2015 to March 2017. Measurements were
performed in the vicinity of major combustion aerosol sources:
Cotonou/traffic (CT), Abidjan/traffic (AT), Abidjan/landfill (AL) and
Abidjan/domestic fires (ADF). We report the weekly PM2.5 mass and
carbonaceous content as elemental (EC) and organic (OC) carbon
concentrations. We also measure the aerosol optical depth (AOD) and the
Ångström exponent in both cities. The average PM2.5 mass
concentrations were 32 ± 32, 32 ± 24 and
28 ± 19 µg m−3 at traffic sites CT and AT and landfill
site AL, respectively. The domestic fire site shows a concentration of
145 ± 69 µg m−3 due to the contribution of smoking and
roasting activities. The highest OC and EC concentrations were also measured
at ADF at 71 ± 29 and 15 ± 9 µg m−3,
respectively, while the other sites present OC concentration between 8 and
12 µg m−3 and EC concentrations between 2 and
7 µg m−3. The OC ∕ EC ratio is 4.3 at CT and 2.0 at AT.
This difference highlights the influence of two-wheel vehicles using gasoline
in Cotonou compared to that of four-wheel vehicles using diesel fuel in
Abidjan. AOD was rather similar in both cities, with a mean value of 0.58 in
Cotonou and of 0.68 in Abidjan. The seasonal cycle is dominated by the large
increase in surface mass concentration and AOD during the long dry season
(December–February) as expected due to mineral dust advection and biomass
burning activities. The lowest concentrations are observed during the short
dry season (August–September) due to an increase in surface wind speed
leading to a better ventilation. On the other hand, the high
PM2.5 ∕ AOD ratio in the short wet season (October–November)
indicates the stagnation of local pollution.
Air quality transcends all scales with in the atmosphere from the local to the global with handovers and feedbacks at each scale interaction. Air quality has manifold effects on health, ecosystems, ...heritage and climate. In this review the state of scientific understanding in relation to global and regional air quality is outlined. The review discusses air quality, in terms of emissions, processing and transport of trace gases and aerosols. New insights into the characterization of both natural and anthropogenic emissions are reviewed looking at both natural (e.g. dust and lightning) as well as plant emissions. Trends in anthropogenic emissions both by region and globally are discussed as well as biomass burning emissions. In terms of chemical processing the major air quality elements of ozone, non-methane hydrocarbons, nitrogen oxides and aerosols are covered. A number of topics are presented as a way of integrating the process view into the atmospheric context; these include the atmospheric oxidation efficiency, halogen and HOx chemistry, nighttime chemistry, tropical chemistry, heat waves, megacities, biomass burning and the regional hot spot of the Mediterranean. New findings with respect to the transport of pollutants across the scales are discussed, in particular the move to quantify the impact of long-range transport on regional air quality. Gaps and research questions that remain intractable are identified. The review concludes with a focus of research and policy questions for the coming decade. In particular, the policy challenges for concerted air quality and climate change policy (co-benefit) are discussed.
Limited data currently exist for atmospheric organic carbon (OC) and black carbon (BC) in South Africa (SA). In this paper OC and BC measured in SA were explored in terms of spatial and temporal ...patterns, mass fractions of the total aerosol mass, as well as possible sources. PM10 and PM2.5 samples were collected at five sites in SA operated within the Deposition of Biogeochemical Important Trace Species-IGAC DEBITS in Africa (DEBITS-IDAF) network. OC were higher than BC concentrations at all sites in both size fractions, while most OC and BC occurred in the PM2.5 fraction. OC/BC ratios reflected the location of the different sites, as well as possible sources impacting these sites. The OC and BC mass fraction percentages of the total aerosol mass varied up to 24% and 12%, respectively. A relatively well defined seasonal pattern was observed, with higher OC and BC measured from May to October, which coincides with the dry season in the interior of SA. An inverse seasonal pattern was observed for the fractional mass contributions of OC and BC to the total aerosol mass, which indicates substantially higher aerosol load during this time of the year. The relationship between OC and BC concentrations with the distance that air mass back trajectories passed by biomass burning fires and large point sources proved that biomass burning fires contribute significantly to regional OC and BC during the burning season, while large point sources did not contribute that significantly to regional OC and BC. The results from a highly industrialised and populated site also indicated that household combustion for space heating contributed at least to local OC and BC concentrations.
ABSTRACT
Few global aerosol models deal with size differentiated inorganic/organic particles. Among them, still fewer ones explicitly treat secondary organic aerosol (SOA) formation. In this context, ...we have coupled the global chemistry‐transport model (CTM) TM4 (Van Velthoven et al., 1996) and the aerosol sectional model ORISAM (ORganic and Inorganic Sectional Aerosol Model, Bessagnet et al., 2002). This new aerosol model ORISAM‐TM4 can accommodate aerosol size distributions with a variable number of diameter sections (bins) between 0.04 μm and over 10 μm and detailed organic/inorganic chemistry coupled with optional gas schemes. Two model versions are presented: a tracer version and a fully detailed eight‐bin version with SOA formation. Focus is made on carbonaceous BC (black carbon) and OC (organic carbon) aerosols. First, significant developments both in ORISAM and in TM4 are discussed in line with the incorporation of updated emission inventories of BC and primary OC (OCp). Then, general comparisons are made between simulated BC and OC concentrations in air and precipitation against worldwide measurements. Also for BC, sensitivity tests using different updated fossil fuel emission inventories are focused over Europe, where emission controls make great strides. The tracer version appears generally satisfactory for BC mostly at background and remote sites, but not for total OC. For this latter, quite significant improvements result from the incorporation of SOA formation in ORISAM‐TM4, instead of estimating OC as being simply proportional to OCp, as done in most existing models. Conclusions and prospects are then given.
Anthropogenic emissions are the result of many different economic sectors, including transportation, power generation, industrial, residential and commercial activities, waste treatment and ...agricultural practices. Air quality models are used to forecast the atmospheric composition, analyze observations and reconstruct the chemical composition of the atmosphere during the previous decades. In order to drive these models, gridded emissions of all compounds need to be provided. This paper describes a new global inventory of emissions called CAMS-GLOB-ANT, developed as part of the Copernicus Atmosphere Monitoring Service (CAMS; https://doi.org/10.24380/eets-qd81, Soulie et al., 2023). The inventory provides monthly averages of the global emissions of 36 compounds, including the main air pollutants and greenhouse gases, at a spatial resolution of 0.1° × 0.1° in latitude and longitude, for 17 emission sectors. The methodology to generate the emissions for the 2000–2023 period is explained, and the datasets are analyzed and compared with publicly available global and regional inventories for selected world regions. Depending on the species and regions, good agreements as well as significant differences are highlighted, which can be further explained through an analysis of different sectors as shown in the figures in the Supplement.
There are very few African regional inventories providing
biofuel and fossil fuel emissions. Within the framework of the DACCIWA
project, we have developed an African regional anthropogenic emission
...inventory including the main African polluting sources (wood and charcoal
burning, charcoal making, trucks, cars, buses and two-wheeled vehicles, open
waste burning, and flaring). To this end, a database on fuel consumption and
emission factors specific to Africa was established using the most recent
measurements. New spatial proxies (road network, power plant geographical
coordinates) were used to convert national emissions into gridded
inventories at a 0.1∘ × 0.1∘ spatial resolution. This
inventory includes carbonaceous particles (black and organic carbon) and
gaseous species (CO, NOx, SO2 and NMVOCs) for the period 1990–2015
with a yearly temporal resolution. We show that all pollutant emissions are
globally increasing in Africa during the period 1990–2015 with a growth rate of 95 %, 86 %, 113 %, 112 %, 97 % and 130 % for BC, OC,
NOx, CO, SO2 and NMVOCs, respectively. We also show that Western Africa is the highest emitting region of BC, OC, CO and NMVOCs, followed by
Eastern Africa, largely due to domestic fire and traffic activities, while
Southern Africa and Northern Africa are the highest emitting regions of
SO2 and NOx due to industrial and power plant sources. Emissions
from this inventory are compared to other regional and global inventories,
and the emissions uncertainties are quantified by a Monte Carlo simulation.
Finally, this inventory highlights key pollutant emission sectors in which
mitigation scenarios should focus on. The DACCIWA inventory (https://doi.org/10.25326/56, Keita et al., 2020) including the annual
gridded emission inventory for Africa for the period 1990–2015 is
distributed by the Emissions of atmospheric Compounds and Compilation of
Ancillary Data (ECCAD) system (https://eccad.aeris-data.fr/, last access: 19 July 2021). For review
purposes, ECCAD has set up an anonymous repository where subsets of the
DACCIWA data can be accessed directly through https://www7.obs-mip.fr/eccad/essd-surf-emis-dacciwa/ (last access: 19 July 2021).
After carbon dioxide (CO2), aerosol black carbon (BC) is considered to be the second most important contributor to global warming. This paper presents equivalent black carbon (eBC) (derived from an ...optical absorption method) data collected from three sites in the interior of South Africa where continuous measurements were conducted, i.e. Elandsfontein, Welgegund and Marikana, as well elemental carbon (EC) (determined by evolved carbon method) data at five sites where samples were collected once a month on a filter and analysed offline, i.e. Louis Trichardt, Skukuza, Vaal Triangle, Amersfoort and Botsalano.Analyses of eBC and EC spatial mass concentration patterns across the eight sites indicate that the mass concentrations in the South African interior are in general higher than what has been reported for the developed world and that different sources are likely to influence different sites. The mean eBC or EC mass concentrations for the background sites (Welgegund, Louis Trichardt, Skukuza, Botsalano) and sites influenced by industrial activities and/or nearby settlements (Elandsfontein, Marikana, Vaal Triangle and Amersfoort) ranged between 0.7 and 1.1, and 1.3 and 1.4 µg m−3, respectively. Similar seasonal patterns were observed at all three sites where continuous measurement data were collected (Elandsfontein, Marikana and Welgegund), with the highest eBC mass concentrations measured from June to October, indicating contributions from household combustion in the cold winter months (June–August), as well as savannah and grassland fires during the dry season (May to mid-October). Diurnal patterns of eBC at Elandsfontein, Marikana and Welgegund indicated maximum concentrations in the early mornings and late evenings, and minima during daytime. From the patterns it could be deduced that for Marikana and Welgegund, household combustion, as well as savannah and grassland fires, were the most significant sources, respectively.Possible contributing sources were explored in greater detail for Elandsfontein, with five main sources being identified as coal-fired power stations, pyrometallurgical smelters, traffic, household combustion, as well as savannah and grassland fires. Industries on the Mpumalanga Highveld are often blamed for all forms of pollution, due to the NO2 hotspot over this area that is attributed to NOx emissions from industries and vehicle emissions from the Johannesburg–Pretoria megacity. However, a comparison of source strengths indicated that household combustion as well as savannah and grassland fires were the most significant sources of eBC, particularly during winter and spring months, while coal-fired power stations, pyrometallurgical smelters and traffic contribute to eBC mass concentration levels year round.
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