Domestic Coal Combustion Research Articles

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.

Comparative analysis of winter composite-PM2.5 in Central Indo Gangetic Plain cities: Combined organic and inorganic source apportionment and characterization, with a focus on the photochemical age effect on secondary organic aerosol formation

To gain insights into air quality dynamics, a high-end instrument such as High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) alongside an Aethalometer was used to measure the Composite PM2.5 (C-PM2.5) in Lucknow and Kanpur during winter. It encompasses non-refractive PM2.5 (NR-PM2.5) and Black Carbon (BC) mass concentrations. Significant variation was noted in average C-PM2.5 concentrations at both sites, as 168.8 ± 61.3 μg m−3 in Lucknow and 90.7 ± 25.7 μg m−3 in Kanpur. Organics emerged as the predominant component, constituting ∼55%–65% of the C-PM2.5 mass, followed by inorganics (24% and 30%) and BC (20% and 8%). The present study employs Positive Matrix Factorization (PMF) on combined organic and inorganic source apportionment, resolving eight and seven source factors at Lucknow and Kanpur, respectively. Both sites exhibit significant contributions from solid-fuel combustion organic aerosol (SFC-OA), with ∼11% in Lucknow and 8% in Kanpur. However, SFC-OA mass concentration in Lucknow, at 24.67 μg m-³, is nearly double that in Kanpur (12.05 μg m-³). This was likely due to domestic coal burning in the nearby households, unregulated open burning, and burning of garbage on roadsides. The study shows that both sites were affected by oxidized biomass burning OA (O-BBOA) emissions, with increased concentration during the night due to dark oxidation by NO3 radicals. The diurnal variation of secondary organic aerosols (SOA), such as O-BBOA and semi-volatile oxygenated OA (SVOOA), shows increasing concentration during daytime hours. Therefore, the photochemical aging (ta) role in SOA formation was analyzed, and it was revealed that the formation might primarily be driven by photochemical oxidation. Additionally, two inorganic-rich factors, sulfate and nitrate-related OA (SO4-OA and NO3-OA) at both sites and additional ammonium chloride-related OA (NH4Cl-OA) resolved at Lucknow. Our study shows that NO3-OA and SO4-OA formation was dominated by aqueous phase processes due to high relative humidity and decline in concentration with increasing ta (ta > 30 h) during winter.

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.

The Decline of Paget’s Disease of Bone and Domestic Coal Use—A Hypothesis

The cause of Paget’s disease of bone (PDB) is unknown. It emerged as a distinct entity in Britain in the late nineteenth century when it was prevalent, and florid presentation not uncommon. Epidemiological surveys in the 1970s showed that Britain had a substantially higher prevalence of PDB than any other country. Studies in the late twentieth and early twenty-first centuries have documented an unexplained change in presentation, with a greatly reduced prevalence and less severe disease than formerly. The emergence of PDB in Britain coincided with rapid industrialization which, in turn, was driven by the use of coal for energy. In the home, bituminous coal was customarily burnt on an open hearth for heating. Using data on coal production, population size, and estimates of domestic use, the estimated exposure to domestic coal burning rose threefold in Britain during the nineteenth century and began to fall after 1900. This pattern fits well with the decline in PDB documented from death certification and prevalence surveys. Colonists moving from Britain to North America, Australia and New Zealand established coal mines and also used coal for domestic heating. PDB was found in these settler populations, but was largely absent from people indigenous to these lands. In all parts of the world PDB prevalence has fallen as the burning of coal in open hearths for domestic heating has reduced. The nature of the putative factor in coal that could initiate PDB is unknown, but possible candidates include both organic and inorganic constituents of bituminous coal.

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).

High contribution of vehicular exhaust and coal combustion to PM2.5-bound Pb pollution in an industrial city in North China: An insight from isotope

Although industrial emissions are the major pollution source of PM2.5-bound Pb, which affects air quality in cities, their influence has gradually decreased with the enhancement of industrial control in recent years. Thus, at present, the source of PM2.5-bound Pb is unclear, especially in an industrial city in North China. In this study, by incorporating the stable Pb isotopic compositions into a Bayesian isotope mixing model (MixSIAR), source apportionment of PM2.5-bound Pb was conducted during autumn and winter in 2017, and summer in 2018 in Changzhi. The daily average concentrations of PM2.5 and PM2.5-bound Pb during the study period were lower than the second-grade limit value of China (75 μg m−3) and the Chinese National Ambient Air Quality Standard (1 μg m−3), respectively. The pollution sources of PM2.5-bound Pb were fully distinguishable using Pb isotopes. In Changzhi, the 206Pb/207Pb ratio in soil (average: 1.0891) and exhaust dust from gasoline (average: 1.0832) and diesel (average: 1.0814) showed low levels of Pb isotope signature in Changzhi, whereas the rest of the source exhibited Pb isotope signature levels. The source apportionment results revealed that in an industrial city with many steel and coking plants, the primary source of PM2.5-bound Pb were motor vehicle emission (29.7%) and coal combustion (26.9%), rather than industrial emission (26.5%). Moreover, seasonal variations in PM2.5 of Pb sub-sources were observed: soil dust (21.7% and 18.4%) and diesel motor vehicles emission (16.4% and 15.6%) in summer and autumn; domestic coal combustion (17.1%) and coal-fired power plant emission (15.5%) in winter. The carcinogenic risk from motor vehicle emission in autumn was higher than that from industrial and coal sources in winter, and higher than that from motor vehicle sources in summer. This finding is a critical evidence of an anomalistic enrichment of PM2.5-bound Pb in an industrial city. These results obtained through Pb isotopic composition and MixSIAR model also improved the accuracy of source apportionment of atmospheric PM2.5-bound Pb, representing a high scientific significance and reference value for Pb pollution control in North China.

Detection and Assessments of Sources and Health Hazards Caused by Heavy Metals in the Dust of Urban Streets in Harbin, Northeast China

To investigate heavy metals (HMs) in the dust of the urban streets and evaluate health hazards through dust pollution exposure, this research implements an analysis method called principal component analysis and a model called positive matrix factorization to investigate the associations between HMs and their plausible allocation of sources. A total number of 118 dust samples were collected from Harbin, China, which is one of the most eloquent industrial hubs and tourist destinations. The results suggest that the mean concentrations of Cd, Cr, Cu, Zn, Ni, Pb, and Mn are 1.79 ± 1.618, 67.23 ± 32.84, 57.76 ± 51.50, 328.52 ± 117.62, 27.11 ± 4.66, 83.03 ± 25.39, and 745.34 ± 153.22 mg kg−1, respectively. The erratic enrichment of Cu, Zn, Pb, and Cd is succeeded by a geo-accumulation index and the factors that are used for enrichment. Both the spatial distribution and correlation analysis imply that Cu, Zn, Pb, and Cd can be controlled by anthropogenic activities. On the contrary, Cr, Mn, and Ni can be ascribed to natural sources. The hazard quotients are less than 1, and the hazard indexes for seniors and kids are 0.129 and 0.852, respectively. So, kids had more non-carcinogenic hazards than the older individuals did. Both groups have carcinogenic risks of less than 1 × 10−6. The results indicated that street dust could not be potentially accepted as a health hazard for dwellers. Cu, Zn, Pb, Cr, Ni, and Cd existed in the street dust of the research region and have been influenced by the combination of industrial and traffic sources and domestic coal combustion, and the parent material that forms soil affects the levels of Mn. A model, called the PMF, is implemented in the study of street dust pollution sources, enhancing the reliability and accuracy of pollution source determination, and presenting some potential applications.

The toxicity emissions and spatialized health risks of heavy metals in PM2.5 from biomass fuels burning

The widespread and high use of biomass fuels (BF) by farmers contribute to air pollution-associated health impacts. However, the toxicity and spatial health risks of heavy metals in PM2.5 from BF burning, especially for elements (Cr, As, Cd, Hg, and Pb) listed as hazardous air pollutants (HAPs) in China, remain unknown on the national scale. This study tested the emission factors (EFs) of 18 heavy metals in PM2.5 for 23 BF sources throughout China. Then, complete emission results for heavy metals in PM2.5 from BF burning in China were estimated using the measured EFs and a field survey. Finally, the GEOS-Chem and Risk Quotients models were utilized to calculate the spatialized health risks from heavy metals in PM2.5 for the first time, including the gridded hazard index (HI) and carcinogenic risk (CR). Overall, the measured total EFs of 18 heavy metals in PM2.5 for 23 BF sources ranged from 5.13 mg kg−1 to 24.14 mg kg−1, and the sum EFs of hazardous elements (Cr, As, Cd, Hg, and Pb) varied from 0.45 mg kg−1 to 7.26 mg kg−1. The results indicated that the emissions of Fe, Zn, Pb, Cd, and Cu in PM2.5 from BF burning were the highest, with emissions of 1440.4, 801.8, 434.8, 399.5, and 397.4 Mg, respectively, in 2014. The emissions of other hazardous elements (Cr, As and Hg) in PM2.5 from BF burning were 203.7, 68.67, and 6.36 Mg, respectively. Compared with other anthropogenic sources, the emissions of As (66.7 Mg) from domestic coal burning were similar to those from BF burning, while the emissions of Cr (98.7 Mg) and Cd (102.7 Mg) were much lower for coal. Former studies might have underestimated the toxicity of Cr, As, and Cd by ignoring the emissions from BF burning. Spatially, the hazardous elements exhibited higher emission intensities in the Sichuan Basin, Northeast China Plain, and North China Plain, which exceeded 200, 55, 350, 5 and 350 g yr−1 for Cr, As, Cd, Hg, and Pb, respectively. The monthly emissions of hazardous elements were the highest in winter (January, February, and December), accounting for 41% of the total emissions. On the national scale, the gridded health risk of hazardous elements attributable to BF burning exhibited a relatively high level and spatial heterogeneity. The national HI for children (≤2.8 × 10−2) and adults (≤1.5 × 10−2) were all far lower than the acceptable level (HI ≤ 1). However, the CR in rural areas of Shanxi, Hebei, Beijing, and Henan (1 × 10−6 to 2.7 × 10−6) reached 2.7 times higher than the acceptable level (CR ≤ 1 × 10−6). These results highlighted that when aiming to mitigate the heavy metals exposure risk in the general population, BF burning emissions should be carefully considered. The governments should improve the awareness of the toxicity and health risks from BF burning. which may reduce the willingness of farmers to use BF sources and further promote the rural energy transition and utilization systematically.

Indoor PM0.1 and PM2.5 in Hanoi: Chemical characterization, source identification, and health risk assessment

This study attempted to provide comprehensive insights into the chemical composition, source identification, and health risk assessment of indoor particulate matter (PM) in urban areas of Vietnam. Three hundred and twenty daily samples of PM0.1 and PM2.5 were collected at three different types of dwellings in Hanoi in two seasons, namely summer and winter. The samples were analyzed for 10 trace elements (TEs), namely Cr, Mn, Co, Cu, Ni, Zn, As, Cd, Sn, and Pb. The daily average concentrations of indoor PM0.1 and PM2.5 in the city were in the ranges of 7.0–8.9 μg/m3 and 43.3–106 μg/m3, respectively. The average concentrations of TEs bound to indoor PM ranged from 66.2 ng/m3 to 216 ng/m3 for PM0.1 and 391 ng/m3 to 2360 ng/m3 for PM2.5. Principle component analysis and enrichment factor were applied to identify the possible sources of indoor PM. Results showed that indoor PM2.5 was mainly derived from outdoor sources, whereas indoor PM0.1 was derived from indoor and outdoor sources. Domestic coal burning, industrial and traffic emissions were observed as outdoor sources, whereas household dust and indoor combustion were found as indoor sources. 80% of PM2.5 was deposited in the head airways, whereas 75% of PM0.1 was deposited in alveolar region. Monte Carlo simulation indicated that the intake of TEs in PM2.5 can lead to high carcinogenic risk for people over 60 years old and unacceptable non-carcinogenic risks for all ages at the roadside house in winter.

Emission and spatialized health risks for trace elements from domestic coal burning in China

Residential coal combustion (RCC) emission exhibited obvious daily variation, while no real-time estimation of air pollutants from RCC has been reported, as the shortages of corresponding activity dataset and emission factors with high time resolution. A real-time monitoring platform for RCC emission was established. Hourly emission factors of 18 typed of TEs from eleven kinds of chunk coals and nine kinds of honeycomb coals burning in China were obtained. The monthly and hourly coal consumption amounts were calculated with reference and our field survey. Then the hourly TEs emission inventories from RCC were established in China. GEOS-Chem and Risk Quotients Models were utilized to map the spatialized health risks of hazardous elements, including the gridded hazard index and carcinogenic risk. The result indicated that the EFs of TEs would be underestimated if the tests only consider flaming conditions. Cu, K, Ca, Zn, and Co were the top five elements from RCC, with corresponding emission amounts as 1397.7, 1054.0, 676.0, 623.5 and 420 tons in 2017, respectively. K, Ti, Fe, Sn, and Sb showed hourly peak values under flaming dominated periods, accounting for 48.2%, 45.9%, 31.8%, 42.8%, and 33.8% of their daily emissions. Other elements (e.g., V, Co, As, Hg and Pb) exhibited higher emissions under smoldering dominated period in nighttime, accounting for 22.2%, 32.9%, 27.6%, 34.7%, and 28.4% of their daily emissions. TEs emission from RCC closely follows the habits of human daily cooking and heating activity. The national HI were lower than the acceptable level (HI ≤ 1) except Sichuan Province (up to 1.2). Higher carcinogenic risks (≥1 × 10-6) occurred in parts of Sichuan, Shanxi, Hunan and Hubei, which were up to 2.0 × 10-5. The high-resolution TEs emission inventories could be useful for future modeling works on the formation and evolution of air pollution and are helpful for human exposure assessment.

Hourly emission estimation of black carbon and brown carbon absorption from domestic coal burning in China

Residential coal combustion (RCC) emission demonstrates obvious daily variation, while no real-time estimation of air pollutants from RCC has been reported, as the limitation of hourly activity data and emission factors. With a dilution sampling system, a high-precision electronic balance, and an Aethalometer Model AE33, a real-time monitoring platform for RCC emission was established. Hourly emission factors (EFs) of BC and absorption emission factors (AEFs) of BrC from eleven kinds of chunk coals and nine kinds of honeycomb coals burning in China were obtained. The monthly and hourly coal consumption amounts were calculated with the activity data from literature reviews and a field survey. The first hourly BC and absorption cross section of BrC emission inventories from RCC were established in China. The historical emission trends (2003–2017) indicated that the policy has rapidly controlled the emission of BC and ACSBrC from RCC in urban area (26.7% and 31.8% decreased, respectively in 2013). While in rural areas, their emission continually increased by 1.2% ~ 5.3% until more strict law enacted in 2017. Emissions of BC and ACSBrC in winter seasons were 60.1 Gg and 1064.1 Gm2, which accounted for 54.3% and 55.1% of the total BC and ACSBrC emissions correspondingly. The peak values of hourly emission of BC and ACSBrC (in 370 nm) normally appeared at 19:00–23:00, accounting for 43.0% and 41.5% of their total daily emission. The low emission periods were at cooking times including 7:00, 12:00, and 17:00 of a day and the whole emission of BC and ACSBrC for the three periods accounted for 1.8% and 2.3% of their daily emission. This high-resolution BC and ACSBrC emission inventories can be useful for future modeling works on the formation and evolution of a haze event, the smoke aging and transportation, as well as corresponding climate and human health effects.

Household air pollution from, and fuel efficiency of, different coal types following local cooking practices in Xuanwei, China

The domestic combustion of smoky (bituminous) coal in the Chinese counties of Xuanwei and Fuyuan, are responsible for some of the highest rates of lung cancer in the world. Cancer rates vary between coal producing regions (deposits) in the area, with coals from Laibin exhibiting particularly high risks and smokeless (anthracite) coal exhibiting lower risks. However, little information is available on the specific burning characteristics of coals from throughout the area. We conducted an extensive controlled burning experiment using coal from multiple deposits in either a traditional firepit or ventilated stove, accompanied by a detailed examination of time-weighted and real-time size-aggregated particle concentrations. Smoky coal caused higher particle concentrations of all sizes than smokeless coal, with variations observed by geological source. Virtually all particle emissions were in the PM2.5 fraction (98% - mass based), and 75% and 46% were in the PM1 and PM0.3 fraction respectively. Real-time concentrations of PM1 and PM0.1 peaked after coal was added and declined afterwards. Ventilation reduced particle concentrations by up to 15-fold and increased the coal burning rate by 1.9-fold. These findings may provide valuable insight for reducing exposure and adverse health effects associated with domestic coal combustion.

Stable carbon isotopic compositions and source apportionment of the carbonaceous components in PM2.5 in Taiyuan, China

To determine the stable carbon isotopic compositions (δ13C) and source apportionment of carbonaceous components in Taiyuan, PM2.5 samples were collected using medium flow samplers (TH-150C) during 4 months in 2014. The δ13C values of organic carbon (OC) and elemental carbon (EC) in PM2.5 were determined using an MAT-251 gas mass spectrometer with a dual inlet system. Moreover, δ13CEC values from industrial and domestic coal combustion were synchronously measured. In March, May, August, and December, the mean δ13COC values were −23.9 ± 0.9‰, −25.2 ± 0.2‰, −25.3 ± 0.6‰, and −22.9 ± 1.0‰, respectively; the corresponding δ13CEC values were −23.8 ± 0.8‰, −24.2 ± 0.5‰, −25.3 ± 0.4‰, and −23.8 ± 0.3‰; and the corresponding δ13CTC values were −23.8 ± 0.7‰, −24.8 ± 0.2‰, −25.3 ± 0.4‰, and −23.2 ± 0.6‰. Notable differences were observed in temporal distributions of stable carbon isotopic compositions of OC, EC, and total carbon (TC). The heavier δ13CEC values in December and March was caused by increased coal combustion and C4 plant burning during the heating season. The δ13CEC value was heavier than the δ13COC value in May, whereas the opposite was true in December. The δ13COC value may have been changed in atmospheric reactions during secondary organic aerosols formation in May and photochemical aging in December. There was almost no difference between δ13COC and δ13CEC in March and August. Source apportionment suggest that the EC sources in Taiyuan during the 4 months were different. EC in March and December was mainly due to fossil fuels (93.8%) and C4 plant burning (6.2%), EC in May was mainly affected by industrial coal combustion (50.0%) and vehicle exhaust (50.0%), and EC in August was the comprehensive result of fossil fuels (63.6%) and charcoal burning (36.4%). These results may enhance understanding of the sources of carbonaceous components in fine particles and may provide valuable data for environmental management.

Source apportionment of ambient PM10−2.5 and PM2.5 for the Vaal Triangle, South Africa

The Vaal Triangle Airshed Priority Area (VTAPA), like other priority areas in South Africa, has an air pollution problem. Understanding the sources contributing to air pollution in this priority area will assist in the selection and implementation of appropriate control strategies. For this study, aerosol samples in the coarse (PM10-2.5) and fine (PM2.5) fraction were collected at four sites in the VTAPA during summer/autumn, winter, and spring. The contributing sources were identified and characterised based on the elemental and ionic compositions obtained through X-ray fluorescence and ion chromatography analysis. The highest seasonal median concentrations of PM10-2.5 (116 μg/m3) and PM2.5 (88 μg/m3) were observed in Sharpeville during the winter. The lowest median concentrations of PM10-2.5 (25 μg/m3) and PM2.5 (18 μg/m3) were detected in Zamdela during the summer/autumn period. At all sites, there was a high abundance of crustal elements in PM10-2.5 and a dominance of coal and biomass combustion-related elements in PM2.5. The Positive Matrix Factorisation receptor model identified dust-related and secondary aerosols as the major contributing sources of PM10-2.5. PM2.5 contributions were predominantly from coal burning for Sebokeng and Sharpeville and from industry, wood and biomass burning, and secondary aerosols for Kliprivier and Zamdela. The results of this study identify the main sources contributing to particulate air pollution in the VTAPA and provide local authorities with valuable information for decision-making.Significance:
 
 Dust, industry, domestic coal burning, vehicles, and wood and biomass combustion are the key sources of particulate air pollution in the VTAPA that need to be prioritised by decision-makers.
 Although Sebokeng and Sharpeville are located within the vicinity of industries, domestic coal burning has a greater contribution to particulate loading at these sites.
 Results from this study will assist in the design of local municipality air quality management plans for the VTAPA.

Variation in chemical composition and sources of PM2.5 during the COVID-19 lockdown in Delhi

The Government of India (GOI) announced a nationwide lockdown starting 25th March 2020 to contain the spread of COVID-19, leading to an unprecedented decline in anthropogenic activities and, in turn, improvements in ambient air quality. This is the first study to focus on highly time-resolved chemical speciation and source apportionment of PM2.5 to assess the impact of the lockdown and subsequent relaxations on the sources of ambient PM2.5 in Delhi, India. The elemental, organic, and black carbon fractions of PM2.5 were measured at the IIT Delhi campus from February 2020 to May 2020. We report source apportionment results using positive matrix factorization (PMF) of organic and elemental fractions of PM2.5 during the different phases of the lockdown. The resolved sources such as vehicular emissions, domestic coal combustion, and semi-volatile oxygenated organic aerosol (SVOOA) were found to decrease by 96%, 95%, and 86%, respectively, during lockdown phase-1 as compared to pre-lockdown. An unforeseen rise in O3 concentrations with declining NOx levels was observed, similar to other parts of the globe, leading to the low-volatility oxygenated organic aerosols (LVOOA) increasing to almost double the pre-lockdown concentrations during the last phase of the lockdown. The effect of the lockdown was found to be less pronounced on other resolved sources like secondary chloride, power plants, dust-related, hydrocarbon-like organic aerosols (HOA), and biomass burning related emissions, which were also swayed by the changing meteorological conditions during the four lockdown phases. The results presented in this study provide a basis for future emission control strategies, quantifying the extent to which constraining certain anthropogenic activities can ameliorate the ambient air. These results have direct relevance to not only Delhi but the entire Indo-Gangetic plain (IGP), citing similar geographical and meteorological conditions common to the region along with overlapping regional emission sources. Summary of main findingsWe identify sources like vehicular emissions, domestic coal combustion, and semi-volatile oxygenated organic aerosol (SVOOA) to be severely impacted by the lockdown, whereas ozone levels and, in turn, low-volatility oxygenated organic aerosols (LVOOA) rise by more than 95% compared to the pre-lockdown concentrations during the last phase of the lockdown. However, other sources resolved in this study, like secondary chloride, power plants, dust-related, hydrocarbon-like organic aerosols (HOA), and biomass burning related emissions, were mainly driven by the changes in the meteorological conditions rather than the lockdown.

Persistent residential burning-related primary organic particles during wintertime hazes in North China: insights into their aging and optical changes

Abstract. Primary organic aerosols (POAs) are a major component of PM2.5 in winter polluted air in the North China Plain (NCP), but our understanding of the atmospheric aging processes of POA particles and the resulting influences on their optical properties is limited. As part of the Atmospheric Pollution and Human Health in a Chinese Megacity (APHH-Beijing) program, we collected airborne particles at an urban site (Beijing) and an upwind rural site (Gucheng, Hebei province) in the NCP during 13–27 November 2016 for microscopic analyses. We confirmed that large numbers of light-absorbing spherical POA (i.e., tarball) and irregular POA particles with high viscosity were emitted from domestic coal and biomass burning at the rural site and were further transported to the urban site during regional wintertime hazes. During the heavily polluted period (PM2.5 > 200 µg m−3), more than 60 % of these burning-related POA particles were thickly coated with secondary inorganic aerosols (named as core–shell POA–SIA particles) through the aging process, suggesting that POA particles can provide surfaces for the heterogeneous reactions of SO2 and NOx. As a result, during the heavily polluted period, their average particle-to-core diameter ratios at the rural and urban sites increased to 1.60 and 1.67, respectively. Interestingly, we found that the aging process did not change the morphology and sizes of POA cores, indicating that the burning-related POA particles are quite inert in the atmosphere and can be transported over long distances. Using Mie theory we estimated that the absorption capacity of these POA particles was enhanced by ∼ 1.39 times in the heavily polluted period at the rural and urban sites due to the “lensing effect” of secondary inorganic coatings. We highlight that the lensing effect on burning-related POA particles should be considered in radiative forcing models and authorities should continue to promote clean energy in rural areas to effectively reduce primary emissions.

First High-Resolution Emission Inventory of Levoglucosan for Biomass Burning and Non-Biomass Burning Sources in China.

Levoglucosan (LG) emitted from non-biomass burning (non-BB) sources has given rise to biased or even unreasonable source identification results when adopting LG as a distinct marker of biomass burning (BB). The estimation of LG emission and its spatiotemporal variation for various sources are the keys to reducing uncertainty. This study first developed a LG emission inventory for China from 25 sub-type sources belonging to eight categories, with a 3 km × 3 km spatial resolution and monthly distribution. The total LG emission in 2014 was 145.7 Gg. Domestic BB and open BB contributed 39.2 and 34.3% of the total emission. Non-BB sources, including municipal solid waste burning (9.7%), firework burning (9.6%), meat cooking (5.4%), domestic coal burning (1.5%), ritual item burning (0.2%), and industrial coal burning (0.1%), contributed to 26.5% of the total emission. LG emission varied spatially and temporally. Non-BB sources have a significant spatiotemporal impact on BB source contributions, even in high BB emission regions or in sowing, harvesting, and winter heating seasons. The local BB contributions have been substantially overestimated by 4.28-369% in previous studies, wherein LG was solely referred to as the BB source. By 2018, LG emission from BB might decrease to 63.9% of its total emission. This high-resolution LG emission inventory can be greatly useful for source identification studies in China. It also supports future research on the modeling of smoke aging and pollution control.

Review on Health Impacts from Domestic Coal Burning: Emphasis on Endemic Fluorosis in Guizhou Province, Southwest China.

Endemic fluorosis in Guizhou Province, Southwest China was firstly reported by Lyth in 1946 and was extensively concerned since the early 1980s. Initially, the pathological cause of endemic fluorosis in Guizhou Province was instinctively ascribed to the drinking water. However, increasing evidences pointed that the major exposure route of fluorine for the local residents is via the roasted foodstuffs, especially the roasted pepper and corn. Source of fluorine in roasted foodstuffs was once blamed on the local coal and subsequently imputed to clay mixed in the coal. In fact, both are probably the source. Geogenic fluorine concentration in soil and clay is indeed high in Guizhou Province, but is not likely to be the direct cause for endemic fluorosis. The real culprit for endemic fluorosis in Guizhou Province is the unhealthy lifestyle of the local residents, who usually roasted their foodstuffs using local coal or briquettes (a mixture of coal and clay), resulting in the elevated fluorine in roasted foodstuffs. Nowadays, endemic fluorosis in Guizhou Province has substantially mitigated. Nevertheless, millions of confirmed cases of dental fluorosis remain left. In addition to endemic fluorosis, other health problems associated with domestic coal burning may also exist, because of the enrichment of toxic/harmful elements in the local coal. It is necessary to determine how serious the situation is and find out the possible solution. As people in other developing countries may suffer from similar health issues, same health issues around the world deserve more attention.

Comprehensive and high-resolution emission inventory of atmospheric pollutants for the northernmost cities agglomeration of Harbin-Changchun, China: Implications for local atmospheric environment management

Using a bottom-up estimation method, a comprehensive, high-resolution emission inventory of gaseous and particulate atmospheric pollutants for multiple anthropogenic sectors with typical local sources has been developed for the Harbin-Changchun city agglomeration (HCA). The annual emissions for CO, NOx, SO2, NH3, VOCS, PM2.5, PM10, BC and OC during 2017 in the HCA were estimated to be 5.82 Tg, 0.70 Tg, 0.34 Tg, 0.75 Tg, 0.81Tg, 0.67 Tg, 1.59 Tg, 0.12 Tg and 0.26 Tg, respectively. For PM10 and SO2, the emissions from industry processes were the dominant contributors representing 54.7% and 49.5%, respectively, of the total emissions, while 95.3% and 44.5% of the total NH3 and NOx emissions, respectively, were from or associated with agricultural activities and transportation. Spatiotemporal distributions showed that most emissions (except NH3) occurred in November to March and were concentrated in the central cities of Changchun and Harbin and the surrounding cities. Open burning of straw made an important contribution to PM2.5 in the central regions of the northeastern plain during autumn and spring, while domestic coal combustion for heating purposes was significant with respect to SO2 and PM2.5 emissions during autumn and winter. Furthermore, based on Principal Component Analysis and Multivariable Linear Regression model, air temperature, relative humidity, electricity and energy consumption, and the urban and rural population were optimized to be representative indicators for rapidly assessing the magnitude of regional atmospheric pollutants in the HCA. Such indicators and equations were demonstrated to be useful for local atmospheric environment management.

Morphology and elemental analysis of freshly emitted particles from packed-bed domestic coal combustion

This study was conducted in a laboratory-controlled environment to analyse the physical properties and elemental composition of coal combustion particles in a brazier. Particles were sampled ~1 m above the stove, using a partector. Particles were collected on gold transmission electron microscopy (TEM) grids, and polycarbonate filters for TEM and inductively coupled plasma mass spectrometry (ICP-MS) analysis, respectively. Particles for elemental analysis were collected on a 37 µm polycarbonate filter, and the exhaust was drawn in using a GilAir Plus pump. During sampling, a 2.5 µm cyclone was attached to the sampling cassette to isolate larger particles. Combustion particles emitted during the early stage of combustion were single organic spherical particles with similar characteristics to tarballs. As the combustion progressed, the particle diameter gradually decreased (from 109 nm), and the morphology changed to smaller particles (to 34.3 nm). The particles formed accretion chain structures, showing evidence of agglomeration. Furthermore, a fluffy microstructure, resembling the formation of soot, was formed in the post flaming phase. In the char-burning phase, an irregular structure of semi-spherical particles was formed, showing evidence of mineral particles infused with small carbonaceous particles. Similarly, with the findings of previous studies, the present research also observed organic spherical particles similar to tarballs. Given that during the ignition phase there was a simultaneous burning of wood as kindling and coal, the provenance of these particle emissions can be attributed to both coal and wood.