ABSTRACT
The mean mass concentrations of black carbon (BC), biomass burning (BC)bb, and fossil fuel combustion (BC)ff have been estimated during March-May 2020 (during the COVID-19 outbreak) and March-May 2019 at a semiarid region of Agra over the Indo-Gangetic basin region. The daily mean mass concentration of BC in 2020 and 2019 was 3.9 and 6.9 µg m-3, respectively. The high monthly mean mass concentration of BC was found to be 4.7, 3.4 and 3.3 µg m-3 in Mar-2020, Apr-2020, and May-2020, respectively, whereas in Mar-2019, Apr-2019, and May-2019 was 7.7, 7.5 and 5.4 µg m-3, respectively. The absorption coefficient (babs) and absorption angstrom exponent (AAE) of black carbon were calculated. The highest mean AAE was 1.6 in the year 2020 (Mar-May 2020) indicating the dominance of biomass burning. The mean mass concentration of fossil fuel (BC)ff and biomass burning (BC)bb is 3.4 and 0.51 µg m-3, respectively, in 2020 whereas 6.4 and 0.73 µg m-3, respectively, in 2019. The mean fraction contribution of BC with fossil fuel (BC)ff was 82.1 ± 13.5% and biomass burning (BC)bb was 17.9 ± 4.3% in 2020, while in 2019, fossil fuel (BC)ff was 86.7 ± 13.5% and biomass burning (BC)bb was 13.3 ± 6.7%. The population-weighted mean concentration of BC, fossil fuel (BC)ff, and biomass burning (BC)bb has been calculated. The health risk assessment of BC has been analyzed in the form of attributable relative risk factors and attributed relative risk during the COVID-19 outbreak using AirQ + v.2.0 model. The attributable relative risk factors of BC were 20.6% in 2020 and 29.4% in 2019. The mean attributed relative risk per 10,000,000 populations at 95% confidence interval (CI) due to BC was 184.06 (142.6-225.2) in 2020 and 609.06 (418.3-714.6) in 2019. The low attributed factor and attributed relative risk in 2020 may be attributed to improvements in air quality and a fall in the emission of BC. In 2020, due to the COVID-19 pandemic, the whole country faced the biggest lockdown, ban of the transportation of private vehicles, trains, aircraft, and construction activities, and shut down of the industry leading to a fall in the impact of BC on human health. Overall, this was like a blessing in disguise. This study will help in future planning of mitigation and emission control of air pollutants in large and BC in particular. It only needs a multipronged approach. This study may be like torch bearing to set path for mitigation of impacts of air pollution and improvement of air quality.
ABSTRACT
During the first half of 2020, the Italian government imposed several restrictions to limit the spread of the COVID‐19 pandemic: at the beginning of March, a heavy lockdown regime was introduced leading to a drastic reduction of traffic and, consequently, traffic‐related emissions. The aim of this study is to evaluate the effects of these restrictions on pollutant concentrations close to a stretch of the Italian A22 motorway lying in the Alpine Adige valley. In particular, the analysis focuses on measured concentrations of nitrogen dioxide (NO2) and black carbon (BC). Results show that, close to the motorway, NO2 concentrations dropped by around 45% during the lockdown period with respect to the same time period of the previous 3 years. The equivalent analysis for BC shows that the component related to biomass burning, mostly due to domestic heating, was not particularly affected by the restrictions, while the BC component related to fossil fuels, directly connected to traffic, plummeted by almost 60% with respect to the previous years. Since atmospheric concentrations of pollutants depend both on emissions and meteorological conditions, which can mask the variations in the emission regime, a random forest algorithm is also applied to the measured concentrations, in order to better evaluate the effects of the restrictions on emissions. This procedure allows for obtaining business‐as‐usual and meteorologically normalized time series of both NO2 and BC concentrations. The results derived from the random forest algorithm clearly confirm the drop in NO2 emissions at the beginning of the lockdown period, followed by a slow and partial recovery in the following months. They also confirm that, during the lockdown, emissions of the BC component due to biomass burning were not significantly affected, while those of the BC component related to fossil fuels underwent an abrupt drop.
ABSTRACT
In this paper we describe our work aimed at designing a system able to measure the particulate matter (PM) concentrations via an optical particle counter (OPC) and simultaneously collect it via standard 2.5 cm filters for laboratory characterization. The Port of Civitavecchia (Italy), one of the most important maritime hubs of the Mediterranean Sea, was selected as a test site for an eight-months monitoring campaign. Comparison between the data provided by our device with those from the referenced and certified monitoring stations from the governmental Regional Agency for the Protection of the Environment (ARPA Lazio) allowed to define clear threshold values (PM10 = 25 μg/m3 and PM2.5 = 10 μg/m3). These threshold values need to be considered when correcting the OPC raw data with respect to the humidity (RH) conditions. The sample material was characterized through optical microscopy and SEM-EDS (scanning electron microscopy coupled with energy-dispersive X-ray fluorescence) and spectroscopy (FTIR, Raman), showing a variegate composition from Al-Fe-oxides to silicates, carbonates, and sulfates, to coal and amorphous carbon together with microplastics and textile fibers. As a final test, we analyzed the PM trends provided by our device during the COVID-19 lockdown, when stringent restrictions in the human activities caused well-known fluctuations in the atmospheric pollution. We again observed an evolution of the PM peaks in excellent agreement with the results yielded by the ARPA Lazio monitoring stations. This result provides a valuable confidence test for our devices highlighting the effectiveness of the presented strategy for airborne particulate-matter monitoring. © 2022
ABSTRACT
Introduction: Air pollutant exposure constitutes a serious risk factor for the emergence or aggravation of (existing) pulmonary disease. Aim(s): In this study, we wanted to investigate if recent and chronic exposures to ambient air pollution (AP) is associated with COVID-19 disease severity in a cohort of hospitalized COVID-19 patients. Method(s): 283 COVID-19 patients were recruited at the time of admission to hospital. Several clinical parameters and outcomes were collected from medical records, including the duration of stay, the early-warning score (EWS), oxygen saturation in blood at admission, admission to the intensive care unit (ICU), and clinical improvement at 30 and at 90 days after the day of admission. Daily exposure levels for PM , PM , NO and black carbon (BC) were modeled using a high-resolution spatiotemporal model. Based on daily exposure levels, average exposures 2 days and 1 week before admission and chronic exposure. Result(s): We observed a significant association between the duration of stay and exposure to PM , PM and NO (recent and chronic exposure). For BC, only chronic exposure (CP) was significantly associated with the duration of stay. On average, the duration of stay increased by 1 to 6 days for an inter-quartile range increase in average exposure to AP in the week before admission. CP was associated with 2 to 3 days increased duration of stay. An increase in PM2.5 and PM10 exposure 1 week before admission was associated with higher EWS. Conclusion(s): Exposure to AP was associated with duration of stay and EWS at the time of admission, which implies a potential link between AP exposure and COVID-19 disease severity, and a significant influence of AP exposure on the pressure of care systems.
ABSTRACT
Airborne black carbon is a strong warming component of the atmosphere. Therefore, curbing black carbon emissions should slow down global warming. The 2019 coronavirus pandemic (COVID-19) is a unique opportunity for studying the response of black carbon to the varied human activities, in particular due to lockdown policies. Actually, there is few knowledge on the variations of black carbon in China during lockdowns. Here, we studied the concentrations of particulate matter (PM2.5) and black carbon before, during, and after the lockdown in nine sites of the Yangtze River Delta in Eastern China. Results show 40-60% reduction of PM2.5 and 40-50% reduction of black carbon during the lockdown. The classical bimodal peaks of black carbon in the morning and evening rush hours were highly weakened, indicating the substantial decrease of traffic activities. Contributions from fossil fuels combustion to black carbon decreased about 5-10% during the lockdown. Spatial correlation analysis indicated the clustering of the multi-site black carbon concentrations in the Yangtze River Delta during the lockdown. Overall, control of emissions from traffic and industrial activities should be efficient to curb black carbon levels in the frame of a 'green public transit system' for mega-city clusters such as the Yangtze River Delta. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10311-021-01327-3.
ABSTRACT
This study aimed to evaluate the levels and phenomenology of equivalent black carbon (eBC) at the city center of Augsburg, Germany (01/2018 to 12/2020). Furthermore, the potential health risk of eBC based on equivalent numbers of passively smoked cigarettes (PSC) was also evaluated, with special emphasis on the impact caused by the COVID19 lockdown restriction measures. As it could be expected, peak concentrations of eBC were commonly recorded in morning (06:00–8:00 LT) and night (19:00–22:00 LT) in all seasons, coinciding with traffic rush hours and atmospheric stagnation. The variability of eBC was highly influenced by diurnal variations in traffic and meteorology (air temperature (T), mixing-layer height (MLH), wind speed (WS)) across days and seasons. Furthermore, a marked "weekend effect” was evidenced, with an average eBC decrease of ∼35% due to lower traffic flow. During the COVID19 lockdown period, an average ∼60% reduction of the traffic flow resulted in ∼30% eBC decrease, as the health risks of eBC exposure was markedly reduced during this period. The implementation of a multilinear regression analysis allowed to explain for 53% of the variability in measured eBC, indicating that the several factors (e.g., traffic and meteorology) may contribute simultaneously to this proportion. Overall, this study will provide valuable input to the policy makers to mitigate eBC pollutant and its adverse effect on environment and human health. © 2022 Elsevier Ltd
ABSTRACT
Emissions of black carbon (BC) and polycyclic aromatic hydrocarbons (PAHs) from various anthropogenic activities are often reported, yet cultural practices such as the multi-day Diwali festival and its influences on the emissions of these compounds are often overlooked. Major activities during this festival include burning rows of oil-filled earthen lamps (diyas) and fireworks (bursting of crackers). A comprehensive field investigation was conducted to document the role of Diwali celebrations on the releases of BC and PAHs during the ongoing Covid pandemic. The results show that large-scale releases of BC and PAHs were observed on the first day of Diwali compared to the remaining four days. BC and PM2.5 mass concentrations throughout the monitoring period ranged from 3.24 to 27.64 µg m−3 and 83.33 to 288.13 µg m−3, respectively. The source apportionment was performed based on the calculated backward trajectories. The results show that the contribution of fossil fuel emission at Adityapur (ADP), Sakchi (SAK), and Gamharia (GMA) was approximately 36.1 %, 34.4 %, and 55.56 %, while biomass burning contribution was approx. 56.9 %, 59.9 %, 41.67 %, respectively. The result showed that fossil fuel emissions were lower compared to biomass combustion during Diwali. Simultaneously, PAHs diagnostic ratio showed that vehicular discharge and coal burning significantly contributed to PAHs at these study sites. © 2022 The Author(s)
ABSTRACT
Particle size distribution is a major factor in the health and climate effects of ambient aerosols, and it shows a large variation depending on the prevailing atmospheric emission sources. In this work, the particle number size distributions of ambient air were investigated at a suburban detached housing area in northern Helsinki, Finland, during a half-year period from winter to summer of 2020. The measurements were conducted with a scanning mobility particle sizer (SMPS) with a particle size range of 16–698 nm (mobility diameter), and the events with a dominant particle source were identified systematically from the data based on the time of the day and different particle physical and chemical properties. During the measurement period, four different types of events with a dominant contribution from either wood-burning (WB), traffic (TRA), secondary biogenic (BIO), or long-range transported (LRT) aerosol were observed. The particle size was the largest for the LRT events followed by BIO, WB, and TRA events with the geometric mean diameters of 72, 62, 57, and 41 nm, respectively. BIO and LRT produced the largest particle mode sizes followed by WB, and TRA with the modes of 69, 69, 46, and 25 nm, respectively. Each event type had also a noticeably different shape of the average number size distribution (NSD). In addition to the evaluation of NSDs representing different particle sources, also the effects of COVID-19 lockdown on specific aerosol properties were studied as during the measurement period the COVID-19 restrictions took place greatly reducing the traffic volumes in the Helsinki area in the spring of 2020. These restrictions had a significant contribution to reducing the concentrations of NOx and black carbon originating from fossil fuel combustion concentration, but insignificant effects on other studied variables such as number concentration and size distribution or particle mass concentrations (PM1, PM2.5, or PM10). © 2022 The Authors
ABSTRACT
Atmospheric black carbon (BC) concentration over a nearly 5 year period (mid-2017–2021) was continuously monitored over a suburban area of Orléans city (France). Annual mean atmospheric BC concentration were 0.75 ± 0.65, 0.58 ± 0.44, 0.54 ± 0.64, 0.48 ± 0.46 and 0.50 ± 0.72 μg m−3, respectively, for the year of 2017, 2018, 2019, 2020 and 2021. Seasonal pattern was also observed with maximum concentration (0.70 ± 0.18 μg m−3) in winter and minimum concentration (0.38 ± 0.04 μg m−3) in summer. We found a different diurnal pattern between cold (winter and fall) and warm (spring and summer) seasons. Further, fossil fuel burning contributed >90 % of atmospheric BC in the summer and biomass burning had a contribution equivalent to that of the fossil fuel in the winter. Significant week days effect on BC concentrations was observed, indicating the important role of local emissions such as car exhaust in BC level at this site. The behavior of atmospheric BC level with COVID-19 lockdown was also analyzed. We found that during the lockdown in warm season (first lockdown: 27 March–10 May 2020 and third lockdown 17 March–3 May 2021) BC concentration were lower than in cold season (second lockdown: 29 October–15 December 2020), which could be mainly related to the BC emission from biomass burning for heating. This study provides a long-term BC measurement database input for air quality and climate models. The analysis of especially weekend and lockdown effect showed implications on future policymaking toward improving local and regional air quality as well. © 2022 Elsevier B.V.
ABSTRACT
Vehicles are a major source of anthropogenic emissions of carbon monoxide (CO), nitrogen oxides (NOx), and black carbon (BC). CO and NOx are known to be harmful to human health and contribute to ozone formation, while BC absorbs solar radiation that contributes to global warming and also has negative impacts on human health and visibility. Travel restrictions implemented during the COVID-19 pandemic provide researchers the opportunity to study the impact of large, on-road traffic reductions on local air quality. Traffic counts collected along Interstate-95, a major eight-lane highway in Maryland (US), reveal a 60% decrease in passenger car totals and an 8.6% (combination-unit) and 21% (single-unit) decrease in truck traffic counts in April 2020 relative to prior Aprils. The decrease in total on-road vehicles led to the near-elimination in stop-and-go traffic and a 14% increase in the mean vehicle speed during April 2020. Ambient near-road (NR) BC, CO, NOx, and carbon dioxide (CO2) measurements were used to determine vehicular emission ratios (ΔBC/ΔCO, ΔBC/ΔCO2, ΔNOx/ΔCO, ΔNOx/ΔCO2, and ΔCO/ΔCO2), with each ratio defined as the slope value of a linear regression performed on the concentrations of two pollutants within an hour. A decrease of up to a factor of two in ΔBC/ΔCO, ΔBC/ΔCO2, ΔNOx/ΔCO2, and in the fraction of on-road diesel vehicles from weekdays to weekends shows diesel vehicles to be the dominant source of BC and NOx emissions at this NR site. We estimate up to a 70% reduction in BC emissions in April 2020 compared to earlier years, and attribute much of this to lower diesel BC emissions resulting from improvements in traffic flow and fewer instances of acceleration and braking. Future efforts to reduce vehicular BC emissions should focus on improving traffic flow or turbocharger lag within diesel engines. Inferred BC emissions from the NR site also depend on ambient temperature, with an increase of 54% in ΔBC/ΔCO from -5 to 20 °C during the cold season, similar to previous studies that reported increasing BC emissions with rising temperature. The default setting of MOVES3, the current version of the mobile emission model used by the US EPA, does not adjust hot-running BC emissions for ambient temperature. Future work will focus on improving the accuracy of mobile emissions in air quality modeling by incorporating the effects of temperature and traffic flow in the system used to generate mobile emissions input for commonly used air quality models.
ABSTRACT
Black carbon (BC) aerosols critically impact the climate and hydrological cycle. The impact of anthropogenic emissions and coastal meteorology on BC dynamics, however, remains unclear over tropical India, a globally identified hotspot. In this regard, we have performed in situ measurements of BC over a megacity (Chennai, 12° 59' 26.5â³ N, 80° 13' 51.8â³ E) on the eastern coast of India during January-June 2020, comprising the period of COVID-19-induced strict lockdown. Our measurements revealed an unprecedented reduction in BC concentration by an order of magnitude as reported by other studies for various other pollutants. This was despite having stronger precipitation during pre-lockdown and lesser precipitation washout during the lockdown. Our analyses, taking mesoscale dynamics into account, unravels stronger BC depletion in the continental air than marine air. Additionally, the BC source regime also shifted from a fossil-fuel dominance to a biomass burning dominance as a result of lockdown, indicating relative reduction in fossil fuel combustion. Considering the rarity of such a low concentration of BC in a tropical megacity environment, our observations and findings under near-natural or background levels of BC may be invaluable to validate model simulations dealing with BC dynamics and its climatic impacts in the Anthropocene.
Subject(s)
Air Pollutants , COVID-19 , Humans , Air Pollutants/analysis , Meteorology , India , Communicable Disease Control , Respiratory Aerosols and Droplets , Fossil Fuels/analysis , Carbon/analysis , Environmental MonitoringABSTRACT
A mobile monitoring campaign was conducted (by bicycle) to assess the black carbon (BC) concentrations in Cluj-Napoca city, Romania, in 2020, before, during and after COVID-19 lock-down. Over the entire study period, the BC concentrations ranged between 1.0 and 25.9 µg/m³ (averaged per street section and period characterized by different traffic conditions). Marked spatial and temporal differences were observed. Observed differences in BC concentrations between locations are attributed to traffic intensities, with average BC concentrations, under normal circumstances, of 6.6-14.3 µg/m³ at roads with high to intense traffic, compared to 2.8-3.1 µg/m³ at areas with reduced traffic, such as residential areas, parks and pedestrian streets. The COVID-19 measures impacted traffic volumes, and hence average BC concentrations decreased from 5.9 µg/m³ to 3.0 µg/m³ during lock-down and in a lower extent to 3.4 µg/m³ and 4.4 µg/m³ in post-lockdown periods with reduced and more normalized traffic. Two approaches to account for variations in background concentrations when comparing different situations in time are assessed. Subtracting background concentrations that are measured at background sites along the monitoring route is an appropriate method to assess spatio-temporal differences in concentrations. A reduction of about 1-2 µg/m³ was observed for the streets with low to medium traffic, and up to 6 µg/m³ at high traffic locations under lockdown. The approach presented in this study, using mobile measurements, is useful to understand the personal exposure to BC along the roads in different seasons and the influence of traffic reduction on BC pollution during prolonged restrictions. All these will support policymakers to reduce pollution and achieve EU directives targets and WHO recommendations.
ABSTRACT
BACKGROUND: The SARS-CoV-2 pandemic has temporarily decreased black carbon emissions worldwide. The use of multi-wavelength aethalometers provides a quantitative apportionment of black carbon (BC) from fossil fuels (BCff) and wood-burning sources (BCwb). However, this apportionment is aggregated: local and non-local BC sources are lumped together in the aethalometer results. METHODS: We propose a spatiotemporal analysis of BC results along with meteorological data, using a fuzzy clustering approach, to resolve local and non-local BC contributions. We apply this methodology to BC measurements taken at an urban site in Santiago, Chile, from March through December 2020, including lockdown periods of different intensities. RESULTS: BCff accounts for 85% of total BC; there was up to an 80% reduction in total BC during the most restrictive lockdowns (April-June); the reduction was 40-50% in periods with less restrictive lockdowns. The new methodology can apportion BCff and BCwb into local and non-local contributions; local traffic (wood burning) sources account for 66% (86%) of BCff (BCwb). CONCLUSIONS: The intensive lockdowns brought down ambient BC across the city. The proposed fuzzy clustering methodology can resolve local and non-local contributions to BC in urban zones.
Subject(s)
Air Pollutants , COVID-19 , Humans , Air Pollutants/analysis , SARS-CoV-2 , Chile , COVID-19/epidemiology , Environmental Monitoring/methods , Communicable Disease Control , Respiratory Aerosols and Droplets , Soot/analysis , Spatio-Temporal Analysis , Carbon/analysis , Particulate Matter/analysisABSTRACT
Many countries imposed lockdown (LD) to limit the spread of COVID-19, which led to a reduction in the emission of anthropogenic atmospheric pollutants. Several studies have investigated the effects of LD on air quality, mostly in urban settings and criteria pollutants. However, less information is available on background sites, and virtually no information is available on particle number size distribution (PNSD). This study investigated the effect of LD on air quality at an urban background site representing a near coast area in the central Mediterranean. The analysis focused on equivalent black carbon (eBC), particle mass concentrations in different size fractions: PM2.5 (aerodynamic diameter Da < 2.5 µm), PM10 (Da < 10 µm), PM10-2.5 (2.5 < Da < 10 µm); and PNSD in a wide range of diameters (0.01-10 µm). Measurements in 2020 during the national LD in Italy and period immediately after LD (POST-LD period) were compared with those in the corresponding periods from 2015 to 2019. The results showed that LD reduced the frequency and intensity of high-pollution events. Reductions were more relevant during POST-LD than during LD period for all variables, except quasi-ultrafine particles and PM10-2.5. Two events of long-range transport of dust were observed, which need to be identified and removed to determine the effect of LD. The decreases in the quasi-ultrafine particles and eBC concentrations were 20%, and 15-22%, respectively. PM2.5 concentration was reduced by 13-44% whereas PM10-2.5 concentration was unaffected. The concentration of accumulation mode particles followed the behaviour of PM2.5, with reductions of 19-57%. The results obtained could be relevant for future strategies aimed at improving air quality and understanding the processes that influence the number and mass particle size distributions.
ABSTRACT
In the field of air analysis, highlights within this review period included: a new in situ method for measuring resuspended road dust arising from vehicular movements;new ink-printed filter reference materials for black- and elemental-carbon measurements;coupling of a scanning mobility particle sizer to a single-particle-ICP-MS instrument for improved nanoparticle characterisation;developments in total-reflection XRF spectrometry for trace analysis and evaluation of vibrational spectroscopic techniques for measuring respirable crystalline silica in the workplace. The increasing availability of ICP-MS/MS instruments is revolutionising the analysis of environmental samples such as waters for trace elements. The advent of the mass shift mode makes some elements such as P and S much easier to quantify and allows the REEs and some radioisotopes to be determined at much lower concentrations than previously possible. Advances in vapour generation methods are mostly limited to photochemical and chemical vapour generation as reflected in the new table listing the main advances. Solid or liquid phase extraction prior to analysis remains of great interest, although a notable trend is the synthesis of new materials rather than optimisation of commercially available chelating agents and columns. The analytical effort presented in a paper is sometimes much less than the effort put into the synthesis of the materials so one wonders about the likelihood of methods actually being used and results replicated. Notable in the analysis of soils and plants was the unusually large number of review articles - possibly because practical research was hampered by the Covid-19 epidemic. Areas of continued growth were research on nanoparticles, the application of high-resolution continuum source AAS for multielement analysis, the development of miniaturised AES instruments that may ultimately be field-portable and application of LIBS to the analysis of plant materials. A concerted effort to characterise natural minerals that are sufficiently homogeneous to act as reference materials in the microanalysis of geological materials has resulted in the availability of new materials for isotope ratio determinations. Tied to this has been research into U-Pb dating of zircon and a variety of other accessory minerals by LA-ICP-MS and SIMS. New chemometric models have been developed to handle the complex LIBS data arising from the analysis of geological matrices in the field and during ore processing. Studies on the use of ICP-MS/MS to reduce polyatomic interferences in geological applications were widespread, reflecting the availability of such instruments. In contrast, the potential offered by integrating LIBS data with those from LA-ICP-MS has only just started to be explored but is likely to increase with the development of commercial instruments. © 2022 The Royal Society of Chemistry.
ABSTRACT
Atmospheric black carbon (BC) concentration over a nearly 5 year period (mid-2017–2021) was continuously monitored over a suburban area of Orléans city (France). Annual mean atmospheric BC concentration were 0.75 ± 0.65, 0.58 ± 0.44, 0.54 ± 0.64, 0.48 ± 0.46 and 0.50 ± 0.72 μg m−3, respectively, for the year of 2017, 2018, 2019, 2020 and 2021. Seasonal pattern was also observed with maximum concentration (0.70 ± 0.18 μg m−3) in winter and minimum concentration (0.38 ± 0.04 μg m−3) in summer. We found a different diurnal pattern between cold (winter and fall) and warm (spring and summer) seasons. Further, fossil fuel burning contributed >90 % of atmospheric BC in the summer and biomass burning had a contribution equivalent to that of the fossil fuel in the winter. Significant week days effect on BC concentrations was observed, indicating the important role of local emissions such as car exhaust in BC level at this site. The behavior of atmospheric BC level with COVID-19 lockdown was also analyzed. We found that during the lockdown in warm season (first lockdown: 27 March–10 May 2020 and third lockdown 17 March–3 May 2021) BC concentration were lower than in cold season (second lockdown: 29 October–15 December 2020), which could be mainly related to the BC emission from biomass burning for heating. This study provides a long-term BC measurement database input for air quality and climate models. The analysis of especially weekend and lockdown effect showed implications on future policymaking toward improving local and regional air quality as well.
ABSTRACT
This study aimed to evaluate the levels and phenomenology of equivalent black carbon (eBC) at the city center of Augsburg, Germany (01/2018 to 12/2020). Furthermore, the potential health risk of eBC based on equivalent numbers of passively smoked cigarettes (PSC) was also evaluated, with special emphasis on the impact caused by the COVID19 lockdown restriction measures. As it could be expected, peak concentrations of eBC were commonly recorded in morning (06:00–8:00 LT) and night (19:00–22:00 LT) in all seasons, coinciding with traffic rush hours and atmospheric stagnation. The variability of eBC was highly influenced by diurnal variations in traffic and meteorology (air temperature (T), mixing-layer height (MLH), wind speed (WS)) across days and seasons. Furthermore, a marked “weekend effect” was evidenced, with an average eBC decrease of ∼35% due to lower traffic flow. During the COVID19 lockdown period, an average ∼60% reduction of the traffic flow resulted in ∼30% eBC decrease, as the health risks of eBC exposure was markedly reduced during this period. The implementation of a multilinear regression analysis allowed to explain for 53% of the variability in measured eBC, indicating that the several factors (e.g., traffic and meteorology) may contribute simultaneously to this proportion. Overall, this study will provide valuable input to the policy makers to mitigate eBC pollutant and its adverse effect on environment and human health.
ABSTRACT
COVID-19 lockdowns enabled researchers to examine air quality in response to economic shifts. However, sub-Saharan African studies are limited, and lockdowns in tropical countries coincided with the wet season. We provide the first record of variations (including diurnal change, daytime and nighttime curfew) in concentrations of black carbon related to fossil fuel burning (BCff) and biomass burning (BCbb) for 2020, focused on three periods: before lockdown (P1: February 8–March 21), lockdown (P2: March 22–May 3), and after lockdown (P3: May 04–June 14) in 2020, with the same periods in 2018 and 2019 used as a control. The annual average BC concentration in Kigali City was 7.8 μg/m3 in 2020. During curfew hours, BCff was reduced by 59% between P2 and P3 (not observed in previous years), which indicates that the lockdown improved transport-related air pollution in Kigali only during curfew hours. No significant change was observed in BCbb concentrations. When COVID-19 restrictions were lifted, black carbon exceeded the same period in previous years. There is evidence for a link between the decline in Rwanda's vehicle use and a reduction in BCff, suggesting that air pollution in African cities could be reduced by promoting sustainable transportation.
ABSTRACT
Emissions of black carbon (BC) and polycyclic aromatic hydrocarbons (PAHs) from various anthropogenic activities are often reported, yet cultural practices such as the multi-day Diwali festival and its influences on the emissions of these compounds are often overlooked. Major activities during this festival include burning rows of oil-filled earthen lamps (diyas) and fireworks (bursting of crackers). A comprehensive field investigation was conducted to document the role of Diwali celebrations on the releases of BC and PAHs during the ongoing Covid pandemic. The results show that large-scale releases of BC and PAHs were observed on the first day of Diwali compared to the remaining four days. BC and PM2.5 mass concentrations throughout the monitoring period ranged from 3.24 to 27.64 µg m-3 and 83.33 to 288.13 µg m-3, respectively. The source apportionment was performed based on the calculated backward trajectories. The results show that the contribution of fossil fuel emission at Adityapur (ADP), Sakchi (SAK), and Gamharia (GMA) was approximately 36.1%, 34.4%, and 55.56%, while biomass burning contribution was approx. 56.9%, 59.9%, 41.67%, respectively. The result showed that fossil fuel emissions were lower compared to biomass combustion during Diwali. Simultaneously, PAHs diagnostic ratio showed that vehicular discharge and coal burning significantly contributed to PAHs at these study sites.
ABSTRACT
Public health Is Increasingly threatened by global warming, land use, and changing wildfire patterns that shape vegetation type, structure, and biodiversity and ultimately affect ecosystem services and our society.1 Uncontrolled large wildfires emit greenhouse gases and aerosols that induce direct and indirect climate feedback through radiative forcing in the atmosphere2 and irreversible changes of natural vegetation, thereby further accelerating climate change and associated fire risks.3 Wildfires are also harmful to human health because they create high pollution concentrations of fine particulate matter that are 2.5 micrometers or smaller (PM2.5) and concentrations of coarse particulate matter that are between 2.5 and 10 micrometers in size. When inhaled, particulate matter significantly increases a myriad of health outcomes, including overall mortality, cardiovascular mortality, and emergency department visits for respiratory morbidity, congestive heart failure, chronic obstructive pulmonary disease, and angina.4,5 Between July and October 2020, high PM2.5 concentrations from massive wildfires surrounding a large regional hospital in the western United States were associated with a 6% increase in COVID-19 cases.6 Risks for developing adverse health effects from wildfire smoke are greatest among people who are living with chronic conditions;who are experiencing intergenerational racial, economic, and housing discrimination;and who are facing social inequities from the COVID-19 pandemic.4The unprecedented recent wildfires in the western United States and their ill effects on human health and society, as well as the multiple other threats to people and places brought about by climate change, draw attention to the increasing urgency of developing new public health approaches and long-term adaptation strategies to support future population health. Observational fire data covering the past few decades give valuable information on current wildfire events.1 However, these data hardly capture long-term trends (i.e., centennial to millennial time scales) of wildfires and associated atmospheric emissions that may help to improve future fire models and thereby provide the base to adapt public health systems.3 To understand long-term trends, natural archives preserve fire history on a wide range ofspatial scales in the past beyond the period of observational fire data;examples include polar and highalpine ice cores;lake, peat, and marine sediment cores.3,8,9 Such paleofire records are based on measurements of the gaseous tracers ammonium and nitrate or particulate matter, such as levoglucosan and black carbon, and charcoal that reflect different components of wildfire-induced atmospheric smoke pollution.8,9 These paleofire records have previously identified complex regional interactions of humans, ecosystems, and climate change.3 Submicron-sized (100-500 nm in diameter) black carbon particles from wildfires and fossil fuel during the industrial era (i.e., the past 250 years) measured in ice cores and lake sediments can be used as a direct tracer for the release of harmful PM2.5 to the atmosphere.8,10 Such paleo black carbon records have been established from both polar and high-alpine glaciers on several continents and are recently developed from lake sediments.10 These found significant changes of fire activity in response to climate and human impact and enhanced pollution levels varying both in time and space. With public health nurses being well positioned to understand population health needs, planetary health, and the health consequences of wildfires, public health nurses can improve upon wildfire adaptation planning and essential public health services by understanding historical perspectives from past fires.9,11,13 Paleofire data provide direct estimates of historical atmospheric emissions from past wildfires and associated harmful concentrations of particulate matter over long distances.