Domestic Burning Research Articles

Exploring the relationship between personal exposure to multiple water-soluble components and ROS in size-resolved PMs in solid fuel combustion households

Water-soluble species are the main components of particulate matters (PMs), which have important impacts on visibility, climate change and human health. Here, personal exposure (PE) to size-resolved PMs from housewives using different solid fuels (biomass and coal) was collected during winter in rural Yuncheng city, Fenwei Plain, China. The concentrations of water-soluble organic carbon (WSOC) and reactive oxygen species (ROS) were higher in the biomass group than coal group, whereas the concentrations of water-soluble inorganic ions and water-soluble nitrogen were higher in the coal group than biomass group. Almost all measured water-soluble components in both groups showed a pattern of increasing concentration with decreasing particle size, with more than 50% of WSOC and water-soluble total nitrogen (WSTN) enriched in PM0.25. The Pearson correlation result was in general agreement with the relationship between water-soluble components and ROS found by random forest model. There was a strong positive correlation between ROS and WSOC in PMs in the coal group, especially in PMs <0.25 μm, which may be due to the emission of a large number of transition metals chelated with WSOC from coal combustion. The contribution of Cl− and F− to ROS was greater in the biomass group. NO2− in both coal and biomass groups had a decent positive effect on ROS generation. The strongest positive linear correlation (R = 0.95) between ROS and K+ in total suspended particulates in the biomass group, whereas there was almost no contribution of K+ to ROS when particle size was distinguished or in random forest model, which reflects the specificity of K+ in inducing ROS. The present study provides new insights for a deeper exploration of the relationship between water-soluble components and oxidative potential in PE PMs from domestic combustion sources.

Morphology and elemental composition of individual solid dust particles: From different sources to the atmosphere

This study investigates the morphology and elemental composition of individual solid dust particles from various sources (e.g., thermal power plant, domestic coal combustion, building construction dust, wind-blown dust, Asian dust storm, and road related dust) to the atmosphere under high and low relative humidity (RH) conditions in a coastal city of north China by using high-resolution electron microscopes. The results showed that distinct variations between dust particles from thermal power plant and domestic coal combustion, despite both using coal as fuel. Specifically, 88.6% (by number) of thermal power plant particles were spherical, whereas only 2 out of 347 particles from domestic coal combustion exhibited a spherical shape. Furthermore, domestic coal combustion particles showed a higher proportion of Ca-rich particles compared to those from thermal power plant. The wind-blown dust and Asian dust storm particles were mainly “Si + Al” subtype (52.0% v.s. 75.3%) and Si-dominant subtype (16.4% v.s. 11.7%) particles, which were mainly from crustal sources. However, wind-blown dust contained a higher fraction of Ca-rich (11.6%) and Fe-rich (5.3%) particles than Asian dust. The building construction dust particles primarily consisted of irregular Ca-dominant (39.4%) and “Ca + Si” subtype (29.8%) particles. Road related dust were also mainly Si-rich particles (52.9%), likely from re-suspended soil, along with a notable presence of spherical (8.0%) and Fe-rich particles (19.3%), possibly linked to vehicle emissions and brake wear. Additionally, relative number percentage of Na-rich particles and the average weigh ratios of Na in the atmospheric particles were higher than those from all above-mentioned source samples, suggesting that sea-salt related particles might be an important source of the atmospheric dust at the coastal city. The results indicated that Ca-rich particles were significantly modified by S and NaCl particles might lose Cl through heterogeneous reactions under higher RH.

Expanded PAH analysis of household air pollution in a rural region of China with high lung cancer incidence

The domestic combustion of locally sourced smoky (bituminous) coal in Xuanwei and Fuyuan counties, China, is responsible for some of the highest lung cancer rates in the world. Recent research has pointed to methylated PAHs (mPAHs), particularly 5-methylchrysene (5MC), within coal combustion products as a driving factor. Here we describe measurements of mPAHs in Xuanwei and Fuyuan derived from controlled burnings (i.e., water boiling tests, WBT, n = 27) representing exposures during stove use, and an exposure assessment (EA) study (n = 116) representing 24 h weighted exposures. Using smoky coal has led to significantly higher concentrations of known and likely human carcinogens than using smokeless coal, including 5MC (3.7 ng/m3 vs. 1.0 ng/m3 for EA samples and 100.8 ng/m3 vs. 2.2 ng/m3 for WBT samples), benzo[a]pyrene (38.0 ng/m3 vs. 7.9 ng/m3 for EA samples and 455.3 ng/m3 vs. 12.0 ng/m3 for WBT samples) and 7,12-dimethylbenz[a]anthracene (1.9 ng/m3 vs. 0.2 ng/m3 for EA samples and 47.7 ng/m3 vs. 0.6 ng/m3 for WBT samples). Mixed effect models for both EA samples and WBT samples revealed clear variation in mPAHs concentrations depending on smoky coal source while stove ventilation was consistently found to reduce measured concentrations (by up to nine fold and 65 fold for EA and WBT samples respectively when using smoky coal). Fuel type had a larger influence on mPAHs concentrations than stove type. These findings indicate that users of smoky coal experience exposure to many PAHs, including known and suspected human carcinogens (especially during cooking activities), many of which are not routinely tested for. Collectively, this provides insights into the potential etiologies of lung cancer in the region and further highlights the importance of targeting clean fuel transitions and stove refinements as the final goal for reducing household air pollution and its associated health risks.

Reconceiving Domestic Burning Controls: Air Quality Alerts, Behavioural Responsive Regulation, and Designing for Compliance.

Domestic combustion emissions pose a growing risk to public health, especially in the UK. Existing responses are polarised, with government advocating use of lower emission fuels and stoves while clean air campaigners call for blanket bans on burning. However, each approach is limited in its ability to control these emissions. An alternative can be found in the U.S.A., where 'burn alert' systems require stove and fireplace users to avoid lighting during periods of actual or projected poor air quality. Given the effectiveness of these regimes, the current study designs and evaluates the effectiveness and acceptability of a burn alert system in the UK for the first time, drawing on the theoretical perspective of behavioural responsive regulation. Fifty participants were recruited to use the system over 2 weeks in winter. The findings illustrate that a voluntary burn alert system can dissuade burning among users. Of those in receipt of an alert, 74% reduced burning frequency or burned for a shorter duration. In total, the alert system prevented at least 178 hours of burning for this group. Qualitative findings show that the consistency of the behavioural response is influenced by technical, structural, and environmental factors, providing key insight into how UK-based burn alert systems could be modified to increase the consistency of compliance in future. The overall conclusion is that burn alerts could be introduced in the UK and beyond, as a means of reducing domestic combustion emissions and their associated public health risks.

Substantial differences in source contributions to carbon emissions and health damage necessitate balanced synergistic control plans in China

China’s strategy to concurrently address climate change and air pollution mitigation is hindered by a lack of comprehensive information on source contributions to health damage and carbon emissions. Here we show notable discrepancies between source contributions to CO2 emissions and fine particulate matter (PM2.5)-related mortality by using adjoint emission sensitivity modeling to attribute premature mortality in 2017 to 53 sector and fuel/process combinations with high spatial resolution. Our findings reveal that monetized PM2.5 health damage exceeds climate impacts in over half of the analyzed subsectors. In addition to coal-fired energy generators and industrial boilers, the combined health and climate costs from energy-intensive processes, diesel-powered vehicles, domestic coal combustion, and agricultural activities exceed 100 billion US dollars, with health-related costs predominating. This research highlights the critical need to integrate the social costs of health damage with climate impacts to develop more balanced mitigation strategies toward these dual goals, particularly during fuel transition and industrial structure upgrading.

Bioconcentration capacity of moss Leskea angustata Tayl., for heavy metals and its application in the atmospheric biomonitoring of a metropolitan area

In this work, the bioconcentration capacity of heavy metals Cd, Cu, Pb and Zn in the moss Leskea angustata Tayl., exposed under laboratory conditions was evaluated, and subsequently the usefulness of moss for the heavy metals' biomonitoring associated with suspended particulate matter in air of the Toluca Valley Metropolitan Area was determined by means of the moss bag technique. To achieve the aims, bioassays were carried out in the laboratory with the moss, the exposure for a period of 6 months of the moss bags in the sites of the Automatic Atmospheric Monitoring Network of the Government of the State of Mexico and their subsequent analysis through of elemental and structural characterization techniques. The results of the bioassays on the moss L. angustata, demonstrate that this moss has adequate bioconcentration capabilities to be used as a biomonitor of heavy metals in polluted areas. The structural characterization of the moss L. angustata, shows that this moss has good adsorption characteristics (presence of functional groups, surface area of 19.87 m2 g−1, average pore diameter equal to 2.86 nm and a total pore volume of 0.014218 cm3 g−1). The significant correlations between Cd–Zn–Pb and between Pb and Zn with PM2.5, as well as a strong correlation between Pb and Zn with PM10, allow us to establish that these three metals have their main origin in the domestic combustion of wood and liquid petroleum gas (LP gas), as well as emissions from agricultural burning in the study area. Cu has a different origin than other metals and PM10 and PM2.5. The findings demonstrate a strong association between anthropogenic activities - such as domestic wood and LP gas combustion, agricultural burning emissions, vehicular emissions, tire wear, and industrial activities - and the detection, entrapment, and accumulation of several heavy metals by L. angustata moss.

The effect of coal-fired power plants on ambient air quality in Mpumalanga province, South Africa, 2014–2018

ABSTRACT Several coal-fired power plants (CFPPs) were built in South Africa, mainly in the central Mpumalanga Province, due to an increase in the demand for Eskom, the national power utility, to keep up with socio-economic growth. The CFPPs, of which 90% are owned by Eskom, generate a significant share of the country’s electricity but contribute to the air pollution experienced in the country. The paper discusses sulphur dioxide (SO2), nitrogen dioxide (NO2) and particulate matter of size less than 10 micrometre (μm) in diameter (PM10), using data from 2014 to 2018. The statistics revealed higher PM10 concentrations during winter than in summer and spring at the Kriel and Komati sites; associated with the higher contribution of domestic burning. The study’s results could influence legislation and policies and help to understand the source of poor ambient air quality by assessing the three pollutants within the area of the selected power plants.

Online observation of light non-methane hydrocarbons (C2–C5) over the central Himalayas: Influence of the Indo-Gangetic Plain region

Studies pertaining to non-methane hydrocarbons (NMHCs) are very limited in South Asia, particularly at high-mountain sites. Therefore, online in-situ observations of light NMHCs (C2–C5) were conducted in the Central Himalayas (Nainital, 1958 m) from January 2017 to December 2020. Additionally, air samples were collected from an Indo-Gangetic Plain (IGP) site (Haldwani, 554 m), located about 18 km and the nearest source regions for the mountain site. The diurnal variations show daytime higher values at the mountain site, which is typical for a pristine site. Correlation analysis and percentage contributions confirm the major roles of biomass burning at the mountain site and Liquefied Petroleum Gas (LPG) emission, automobile and domestic combustion at the IGP site. Nevertheless, the anthropogenic influences also reaches the Himalayan site, mainly in spring, which is confirmed by the concentrated weighted trajectory (CWT) analysis. Such influences are limited to the IGP site in winter, primarily due to the shallower boundary layer. The estimated photochemical age varies from 9 days in winter to 16 days in summer-monsoon. It is shown that the hydroxyl radical reactivity, ozone formation potential (OFP) and secondary organic aerosol formation potential (SOAFP) are 4–6 times higher at the IGP site compared to the Himalayan site. Propylene, ethylene and n-butane are major contributor in these at both sites. Ethane is found to be most abundant (40%) at the Himalayan site, while propane (27%) at the IGP site. An assessment of percentage contribution of different NMHCs in emission inventories for the Himalayan region is suggested.

The newest emission inventory of anthropogenic full-volatility organic in Central China

Organic aerosol (OA) is the largest and most complicated component of aerosols that has significant impacts on human health and global climate. However, current models cannot accurately predict the concentrations and sources of primary and secondary OA due to the oversimplification of traditional organic emission inventories. Traditional emission inventories do not consider important precursors of secondary organic aerosols (SOA), such as semi-volatile and intermediate-volatility organic compounds (SVOCs and IVOCs). To improve the accuracy of OA prediction and source identification, it is essential to refine precursor emissions. In this study, a full-volatility organic compounds emission inventory was established for the Central China, with Henan Province as a representative in 2020. The anthropogenic emissions of ultralow volatility organic compounds (xLVOCs), SVOCs, IVOCs, and VOCs were 53.9 kt, 55.3 kt, 182.1 kt, and 586.3 kt, respectively, effectively filling the gap of 181.3 kt in traditional organic compound emission inventory. Residential biomass burning was identified as the primary contribution source for xLVOCs and SVOCs, accounting for 70.1% and 42.2%, respectively. Industrial process was the main contributor for IVOCs and VOCs, accounting for 31.7% and 44.0% of their emissions, respectively. Meanwhile, the emission of volatile organic compound from different sources showed an increasing trend as volatility increased. The gas-phase emission was 212.1 kt, primarily from industrial process (33.9% contribution), while the particle-phase emission was 79.2 kt, mainly from domestic biomass combustion (65.0% contribution). xLVOCs and SVOCs emissions were mainly concentrated in cities with agricultural activities, such as Zhoukou, while IVOCs and VOCs were concentrated in highly industrialized and urbanized areas, such as Zhengzhou. It is hoped that the incompleteness of emission factors (EFs) for full-volatility organic compounds, which mainly contributes to the uncertainty of this study's results, can be further improved to better understand source contributions.

ИЗ ОПЫТА ЭКСПЛУАТАЦИИ АВТОБУСОВ ЛИАЗ 529222

With a slight mileage of buses of the Likinsky Bus Plant, the engines alternately began to fail with the destruction of cylinder blocks and pistons, the occurrence of compression rings. (Research purpose) The research purpose is searching out for the causes of increased engine oil consumption and emergency failure of foreign-made internal combustion engines. (Materials and methods) The D0836LOH65 engine was chosen as the object of research. We studied the geometry and hardness of oil-removing piston rings. We used a Digital Micro microscope with magnification up to 400x and an electronic hardness tester in accordance with the recommendations of the regulatory and technical documentation. (Results and discussion) It was established by visual inspection that there is uneven wear on the working surfaces of the oil-removing piston rings, and defects in the form of porous formations on the end ones. Wear was recorded in the upper part of the cylinders with the formation of a ledge, black carbon deposits appeared on the bottoms and on the heat belt of the pistons, small longitudinal scratches appeared on the skirts of the pistons. Damage to the inserts has a form characteristic of working in the so-called oil starvation mode. It was determined that the cause of damages in engine parts is the non-compliance of the material of the oil-removing rings, both new and used, with the requirements of the standard for the difference in hardness in a single ring and the total hardness of the surface of the rings. (Conclusions) The detection of the defect is related to the manufacture of rings, the non-compliance of the material of the compression rings of foreign-made engines with the requirements of the domestic standard and the increased consumption of engine oil, which caused emergency damage to diesel engine parts. The transition to the use of domestic internal combustion engines is relevant and necessary in modern conditions. From a practical point of view, it is recommended to check the surface hardness of new compression rings before installation during engine repairs.

Quantification of ambient PM2.5 concentrations adjacent to informal brick kilns in the Vhembe District using low-cost sensors

The widespread exposure to ambient PM2.5 poses a substantial health risk globally, with a more pronounced impact on low- to medium-income nations. This study investigates the spatiotemporal distribution of PM2.5 in the communities hosting informal brickmaking industries in Vhembe District. Utilizing Dylos DC1700, continuous monitoring of PM2.5 was conducted at nine stations adjacent to informal brick kilns from March 2021 to February 2022. The study determined the correction factor for PM2.5 measurements obtained from the Dylos DC1700 when it was collocated with the GRIMM Environmental Dust Monitor 180. Additionally, the diurnal and seasonal variations across monitoring stations were assessed, and potential PM2.5 sources were identified. The study also evaluated the compliance of ambient PM2.5 concentrations across the stations with the South African National Ambient Air Quality Standard (NAAQS) limits. Annual PM2.5 concentrations for the stations ranged from 22.6 to 36.2 μgm−3. Diurnal patterns exhibited peak concentrations in the morning and evening, while seasonal variations showed higher concentrations in winter and lower concentrations in summer and spring. All monitoring stations reported the highest daily exceedance with respect to the daily NAAQS limit in the winter. Major PM2.5 sources included domestic biomass combustion, vehicular emissions, industrial emissions, and construction sites. Well-calibrated low-cost sensors could be employed in suburb regions with scarce air quality data. Findings from the study could be used for developing mitigation strategies to reduce health risks associated with PM2.5 exposure in the area.

Potentially toxic elements in rainwater during extreme rainfall period in the megacity Beijing: Variations, sources, and reuse potential

Air pollution has become a worldwide problem, which resulted in various environmental threats to the human beings and surface ecosystem. It is thus significant to clarify the sink/source process of atmospheric contaminants, such as the potentially toxic elements (PTEs). The rainfall process is a vital sink for atmospheric PTEs, which can effectively reduce their content in atmosphere. However, the understanding blind spot of variations, sources, and reuse potential of rainwater PTEs in megacities (hotspots area of atmospheric PTEs deposition) still existed, particularly in extreme rainfall period. For this, the daily-scale rainwater samples were collected in Beijing City during extreme rainfall period, and the selected PTEs were measured and further analyzed. The results indicated a volume-weighted mean PTEs concentration (in μg/L) order of Zn (10.86) > Mn (3.21) > Fe (0.73) > Cu (0.69) > Ni (0.35) > V (0.22) > Cr (0.09) ≈ Pb (0.09) > Cd (0.04). Zn was the most abundant PTEs, which was 2∼3 magnitude orders greater than the low abundant PTEs, such as Cr, Pb, and Cd. The sources of PTEs and the dissolved processes of atmospheric components (e.g., particulate matter) were the predominant influencing factors of rainwater PTEs variations, and the rainfall amount was also the potential (not the critical) influencing factor, while the influence of rainwater pH is negligible. According to the enrichment factor and multivariate statistical analysis, the Cd, Zn, and Cu were primarily attributed to anthropogenic sources, which were typically derived from fossil fuel burning, vehicle emission, and domestic waste combustion. The crust sources mainly contributed the Fe, Cr, and V, while the other PTEs (Mn, Ni, and Pb) were derived from a combination of human and natural inputs. Reuse potential assessment revealed that the harvested rainwater was suitable for irrigation of urban green space and vegetation (low soil hazard), and may potentially be utilized for drinking purpose under extreme conditions (after addressing the problem of ammonia nitrogen). This work identified the PTEs characteristics in urban wet deposition, which will help knowledge of PTEs biogeochemical cycle and sustainable use of rainwater resources under climate and environmental change.

Comparison of the Analytical Performance of Inductively Coupled Plasma Mass Spectrometry and Instrumental Neutron Activation Analysis Techniques in the Elemental Analysis of Coal Fly Ash

Inductively coupled plasma mass spectrometry (ICP-MS) and instrumental neutron activation analysis (INAA) were applied to study the elemental content of coal combustion residues. Both methods’ analytical applicability and suitability for this type of material were described in detail. A certified reference material, fine fly ash (CTA-FFA-1), was used to examine the capabilities and validation of both methods. A comparison study allowed for the modification of the procedures for these materials (previously elaborated in the Institute of Nuclear Chemistry and Technology), resulting in more accurate data with lower uncertainty. We highlighted that INAA and ICPs complemented each other in the analysis of coal and coal combustion residues. The digestion procedure was an integral part of the measurement and affected the environmental analysis results. Both methods were applied to the chemical characteristics of coal ashes from household furnaces. The hard coal was from Polish, Columbian, and Kazakh mines. The majority of elements had similar concentrations, independently of coal origin. Because ash from domestic coal combustion is used as a fertilizer or an anti-icing agent, we assessed the potential environmental impact via leaching experiments (according to PN-EN 12457-2). The potential risk of soil contamination due to ash dumping around the house and its surroundings was determined as insignificant (for the elements investigated).

Global Anthropogenic Emissions of Full-Volatility Organic Compounds.

Traditional global emission inventories classify primary organic emissions into nonvolatile organic carbon and volatile organic compounds (VOCs), excluding intermediate-volatility and semivolatile organic compounds (IVOCs and SVOCs, respectively), which are important precursors of secondary organic aerosols. This study establishes the first global anthropogenic full-volatility organic emission inventory with chemically speciated or volatility-binned emission factors. The emissions of extremely low/low-volatility organic compounds (xLVOCs), SVOCs, IVOCs, and VOCs in 2015 were 13.2, 10.1, 23.3, and 120.5 Mt, respectively. The full-volatility framework fills a gap of 18.5 Mt I/S/xLVOCs compared with the traditional framework. Volatile chemical products (VCPs), domestic combustion, and on-road transportation sources were dominant contributors to full-volatility emissions, accounting for 30, 30, and 12%, respectively. The VCP and on-road transportation sectors were the main contributors to IVOCs and VOCs. The key emitting regions included Africa, India, Southeast Asia, China, Europe, and the United States, among which China, Europe, and the United States emitted higher proportions of IVOCs and VOCs owing to the use of cleaner fuel in domestic combustion and more intense emissions from VCPs and on-road transportation activities. The findings contribute to a better understanding of the impact of organic emissions on global air pollution and climate change.

Air quality and related health impact in the UNECE region: source attribution and scenario analysis

Abstract. The TM5-FAst Scenario Screening Tool (TM5-FASST) was used to study the influence of abatement policies within and outside the United Nations Economic Commission for Europe (UNECE) region on the exposure to O3 and PM2.5 and associated mortality in the UNECE countries. To that end, the impacts of pollutants derived from different geographic areas and activity sectors were evaluated using ECLIPSE V6b scenarios of air pollutant and greenhouse gas (GHG) emission reduction. The mortalities were attributed to O3 and PM2.5 following the Global Burden of Disease (GBD) approach and allocated to geographic areas (UNECE and non-UNECE) and activity sectors, including natural sources. In addition, a combination of runs designed for the purpose led to allocating exposure to O3 and related mortality to two families of precursors: NOx–VOC and CH4. In this study, the baseline scenario (current legislation scenario, CLE), which assumes that all air quality and greenhouse gas abatement measures adopted by 2018 are fully implemented, is compared with more ambitious scenarios (maximum feasible reduction, MFR). The findings from this comparison indicate that O3 exposure within the UNECE area is more sensitive to measures outside the UNECE region than PM2.5 exposure, even though the latter leads to higher mortality than the former. In the CLE, the mortality associated with O3 exposure in the UNECE region grows steadily from 2020 to 2050. The upward trend is mainly associated with the growing impact of CH4 emissions from areas outside UNECE. Also, the mortality related to NOx–VOC emissions outside UNECE increases in the same period. By comparison, a measurable decrease (13 %) is observed in the mortality attributable to NOx–VOC emissions within UNECE. In the same time window, the mortality associated with PM2.5 exposure in the UNECE region decreases between 2020 and 2040 and then rises until 2050. The PM2.5-related mortality in UNECE is mainly due to anthropogenic emissions within this region followed by natural sources (sea salt and dust) mainly located outside the UNECE region. Between 2020 and 2050, the impact of some UNECE anthropogenic sources on PM2.5-related mortality decreases progressively, in particular road transport, energy production and domestic combustion, while others, namely agriculture and industry, show an upward trend. Finally, the analysis of MFR scenarios confirms that abatement measures in line with UN Sustainable Development Goals (SDGs) and the Paris Agreement can lead to significant co-benefits between air quality and climate policies.

Distribution and Meteorological Control of PM2.5 and Its Effect on Visibility in Northern Thailand

In the dry season, the north of Thailand always experiences reduced air quality, reduced visibility, and public health exposure from the burning of biomass domestically and in surrounding countries. The purpose of this research was to investigate the distribution and the meteorological control of PM2.5 accumulation, as well as its effect on visibility in northern Thailand in 2020. The Geographic Information System (GIS) was applied for the analysis of the spatial distribution, while Pearson’s correlation coefficient was utilized to examine the association between PM2.5 and meteorological variables. The results showed that the PM2.5 concentrations were in the range of 16–195 μg/m3 in 2020. The high level of PM2.5 in Lampang, Chiang Rai, and Chiang Mai provinces was in the range of 150 to 195 μg/m3 from January to May. Favorable meteorological conditions included low wind and relative humidity, and high temperatures contributed to high PM2.5 concentrations in northern Thailand. Domestic burning and burning in neighboring countries contribute to huge amounts of smoke that cause low visibility in northern Thailand, especially at 1 km above ground level, with a reduced visibility in the range of 70–90% for all provinces in April.

Breaking New Ground: Space Agencies and Epidemiologists Partner Up on Particulates

Breaking New Ground: Space Agencies and Epidemiologists Partner Up on Particulates

The Risk of Orofacial Cleft Lip/Palate Due to Maternal Ambient Air Pollution Exposure: A Call for Further Research in South Africa.

Despite being underreported, orofacial cleft lip/palate (CLP) remains in the top five of South Africa's most common congenital disorders. Maternal air pollution exposure has been associated with CLP in neonates. South Africa has high air pollution levels due to domestic burning practices, coal-fired power plants, mining, industry, and traffic pollution, among other sources. We investigated air pollutant levels in geographic locations of CLP cases. In a retrospective case series study (2006-2020) from a combined dataset by a Gauteng surgeon and South African Operation Smile, the maternal address at pregnancy was obtained for 2,515 CLP cases. Data from the South African Air Quality Information System was used to calculate annual averages of particulate matter (PM) concentrations of particles < 10 µm (PM10) and < 2.5 µm (PM2.5). Correlation analysis determined the relationship between average PM2.5/PM10 concentrations and CLP birth prevalence. Hotspot analysis was done using the Average Nearest Neighbor tool in ArcGIS. Correlation analysis showed an increasing trend of CLP birth prevalence to PM10 (CC = 0.61, 95% CI = 0.38-0.77, p < 0.001) and PM2.5 (CC = 0.63, 95% CI = 0.42-0.77, p < 0.001). Hot spot analysis revealed that areas with higher concentrations of PM10 and PM2.5 had a higher proclivity for maternal residence (z-score = -68.2, p < 0.001). CLP birth prevalence hotspot clusters were identified in district municipalities in the provinces of Gauteng, Limpopo, North-West, Mpumalanga, and Free State. KwaZulu-Natal and Eastern Cape had lower PM10 and PM2.5 concentrations and were cold spot clusters. Maternal exposure to air pollution is known to impact the fetal environment and increase CLP risk. We discovered enough evidence of an effect to warrant further investigation. We advocate for a concerted effort by the government, physicians, researchers, non-government organizations working with CLP patients, and others to collect quality data on all maternal information and pollutant levels in all provinces of South Africa. Collaboration and data sharing for additional research will help us better understand the impact of air pollution on CLP in South Africa.

Interference of Past Soil Contaminations in the Biomonitoring of PCB Emissions from a Recovered Derived Fuels (RDFs) Co-Powered Cement Plant

Although the intentional production of polychlorinated biphenyls (PCBs) has totally been banned, these pollutants are still released into the atmosphere by industrial and domestic burning processes and by volatilization from soils locally contaminated by PCB spill-overs. The present work aims at identifying the PCB sources in a mixed land use area of northeastern Italy around a cement plant co-powered with recovered derived fuels (RDFs) from 2018. Leaves of Robinia pseudoacacia trees were systematically sampled over c. 40 km2 in 37 sites and analyzed for 12 dioxin-like and 20 non-dioxin-like congeners. The samples of most sampling sites had a PCB content &lt; LOD, whereas those with higher content were located in urban sites. The spatial distribution of PCB leaf content was not centered on the purported emission sources. The samples of three spatially unrelated sites had high contents of 2, 12 and 18 PCB congeners, with the last two having combinations fully compatible with past commercial mixtures traded under different names. Comparison of these results with those of previous (bio-)monitoring surveys supports the hypothesis that the area has been subjected to punctiform PCB spill-overs, which overwhelm the contribution from present day industrial emissions, comprised of those actually derived from the use of RDFs.

Prediction and assessment of the impact of COVID-19 lockdown on air quality over Kolkata: a deep transfer learning approach

The present study focuses on the prediction and assessment of the impact of lockdown because of coronavirus pandemic on the air quality during three different phases, viz., normal periods (1 January 2018-23 March 2020), complete lockdown (24 March 2020-31 May 2020), and partial lockdown (1 June 2020-30 September 2020). We identify the most important air pollutants influencing the air quality of Kolkata during three different periods using Random Forest, a tree-based machine learning (ML) algorithm. It is found that the ambient air quality of Kolkata is mainly affected with the aid of particulate matter or PM (PM10 and PM2.5). However, the effect of the lockdown is most prominent on PM2.5 which spreads in the air of Kolkata due to diesel-driven vehicles, domestic and commercial combustion activities, road dust, and open burning. To predict urban PM2.5 and PM10 concentrations 24h in advance, we use a deep learning (DL) model, namely, stacked-bidirectional long short-term memory (stacked-BDLSTM). The model is trained during the normal periods, and it shows the superiority over some supervised ML models, like support vector machine, K-nearest neighbor classifier, multilayer perceptron, long short-term memory, and statistical time series forecasting model autoregressive integrated moving average. This pre-trained stacked-BDLSTM is applied to predict the concentrations of PM2.5 and PM10 during the pandemic situation of two cases, viz., complete lockdown and partial lockdown using a deep model-based transfer learning (TL) approach (TLS-BDLSTM). Transfer learning aims to utilize the information gained from one problem to improve the predictive performance of a learning model for a different but related problem. Our work helps to demonstrate how TL is useful when there is a scarcity of data during the COVID-19 pandemic regarding the drastic change in concentration of pollutants. The results reveal the best prediction performance of TLS-BDLSTM with a lead time of 24h as compared to some well-known traditional ML and statistical models and the pre-trained stacked-BDLSTM. The prediction is then validated using the real-time data obtained during the complete lockdown due to COVID second wave (16 May-15 June 2021) with different time steps, e.g., 24h, 48h, 72h, and 96-120h. TLS-BDLSTM involving transfer learning is seen to outperform the said comparing methods in modeling the long-term temporal dependency of multivariate time series data and boost the forecast efficiency not only in single step, but also in multiple steps. The proposed methodologies are effective, consistent, and can be used by operational organizations to utilize in monitoring and management of air quality.