Impact of terephthalic acid emissions from intensive nocturnal biomass incineration on oxidative potential in Seoul, South Korea.

This study investigated the impact of large-scale incineration facilities on PM2.5 levels in Seoul during winter. Due to the challenge of obtaining accurate combustion data from external sources, heat supply records were used as a proxy for combustion activity. To assess health risks, dithiothreitol-oxidative potential (DTT-OP) was analyzed to identify potential hazards to human health. By comparing DTT-OP with PM2.5 sources related to combustion, the study aimed to understand the impact of local pollution sources on human health in Seoul. The diurnal analysis showed that oxidative potential (0.19 µM/m3) and the biomass burning factor (5.53 µg/m3) peaked between 4:00 and 8:00 AM, with lower levels observed from 12:00 to 20:00. A significant correlation was found between combustion sources and oxidative potential, with a high correlation coefficient (r2 = 0.92). The presence of terephthalic acid (TPA) in the Cellulose combustion source profile, which is produced by the pyrolysis of plastics like polyester fiber and polyethylene terephthalate (PET), further supported the link to emissions from incineration facilities. These findings suggest that the biomass burning source is strongly correlated with DTT-OP, indicating a significant association with health risks among various local sources of PM2.5 in Seoul.

Effects of long-range transport on carboxylic acids, chlorinated VOCs, and oxidative potential in air pollution events.

In the context of air quality research, the collection and analysis of fine particulate matter (PM2.5, with a diameter less than 2.5 µm) and volatile organic compound (VOCs) play a pivotal role in understanding and addressing environmental issues across the Korean Peninsula. PM2.5 and VOCs were collected over 4-hr intervals from October 17 to November 26, 2021 during the 2021 Satellite Integrated Joint Monitoring of Air Quality campaign at Olympic Park in the Republic of Korea to understand the factors controlling air quality over the Seoul Metropolitan Area. Source apportionment was performed using the positive matrix factorization (PMF) model incorporating PM2.5 and VOCs. The factor identified by chlorinated VOCs as a major component was presumed to be due to transboundary influx and was referred to as the long-range transport factor. The long-range transport factor of PM2.5 was composed of NO3-, SO42-, NH4+, and di-carboxylic acids. Back trajectory analysis showed that the airflows originated from China and passed through the west coast of Korea to the Korean Peninsula. In the PMF results using PM2.5 and VOCs, long-range transport factors were identified in both analyses, and the high correlation observed between these factors confirms that they were transported from abroad. The dithiothreitol oxidation potential normalized to quinine showed the highest oxidation potential during the same period as the long-range transport factors increased. In conclusion, PM2.5 from external sources significantly contribute to elevated levels of dithiothreitol assay-oxidative potential (DTT-OP) in Korea. The toxic concentration, expressed as the mean ± standard deviation, was determined to be 0.29 ± 0.05 µM/m³, peaking at 0.39 µM/m³. This level is 1.8 times higher than that observed outside the event period. A notable increase in secondary pollutants was observed during these periods. These pollutants are known to enhance oxidative potential, thereby potentially impacting human health.

Insights into national distribution of NH3 concentrations in Republic of Korea: findings from passive sampler observations and implications for sources and management.

Gas-phase NH3 is one of the significant contributors to secondary aerosol formation in the atmosphere, and it is a crucial consideration in any strategy aiming to reduce PM2.5 emissions. This study aimed to investigate the spatial distributions of NH3 in verity source areas in Republic of Korea using passive samplers. NH3 concentrations were observed at 45 locations over a period of approximately 35 weeks, from June 2022 to February 2023. As a result, NH3 concentration was found to be more affected by local sources rather than long-distance influx from outside. The average concentration of NH3 observed in 7 source areas excluding the background area was all less than 20.91 ppb, except for livestock sources. These results suggest that atmospheric NH3 concentrations are significantly influenced from livestock sources. In addition, in major cities, the need for NH3 management was confirmed to be more focused on emissions from automobiles and industrial complexes than emissions from livestock and farmland. Moreover, even for the same source, NH3 concentrations varied depending on the type of livestock species, breeding methods and scale, products produced, crops cultivated, and vehicle traffic volume. These findings indicate the importance of considering factors such as breeding methods and manure treatment practices in emission factors, and it is expected that the results can be used as basic data for NH3 emission estimation and management.

Comparison of the sources and oxidative potential of PM2.5 during winter time in large cities in China and South Korea.

Regional air pollution is rising in Northeast Asia due to increasing energy consumption resulting from a growing population and intensifying industrialization. This study analyzes the sources of air pollution using fine particulate matter (PM2.5) sampling from the atmosphere over Korea and China. We then use this analysis to further investigate the relationship between organic compounds (source tracers) and the oxidative potential of PM2.5. The PM2.5 concentration during winter measured at a measurement stations in Korea showed no significant variation year-to-year. The PM2.5 concentrations measured during winter at a site near Beijing, China were 62.45 µg/m3 in 2018 and 33.07 µg/m3 in 2020. The sources, as determined from PMF, were analyzed at a site in Korea, the sources as secondary nitrate (34.10 %), secondary sulfate (20.20 %), coal combustion (4.01 %), vehicle emission (8.55 %), cooking and biomass burning (18.39 %), dust (8.45 %), and SOA (6.29 %) were identified. At a site in China, secondary nitrate (17.54 %), secondary sulfate (12.03 %), coal combustion (15.53 %), vehicle emission (12.43 %), cooking and biomass burning (9.25 %), dust (26.40 %), secondary organic aerosol (6.82 %) were identified. Our results show secondary organic carbon had a positive association with oxidative potential in Korea while primary organic carbon presented higher correlation with oxidative potential in China. Further, the ECMWF Reanalysis v5 (ERA5) wind field during the high PM2.5 events demonstrated airflow from the west coast of China resulting in high polar organic compounds at the Korean monitoring site. The results further support that aged PM2.5, which contains secondary products, leads to increased oxidative potential. The results presented explain the high concentrations of secondary products and the impact on the biological activities of PM2.5, supporting additional actions to address the impacts of long-range transport of PM2.5.

Assessment of long-range oriented source and oxidative potential on the South-west shoreline, Korea: Molecular marker receptor models during shipborne measurements.

In order to determine the quantitative contributions of PM2.5 on the South-west shoreline of Korea, filter based samplings were conducted in the summertime of 2017 and 2018 (total 32 days) via shipborne measurements using both a high volume and middle volume air sampler. Water-soluble organic carbon, water-soluble ions, organic carbon and elemental carbon, elemental species, and organic molecular markers by Liquid Chromatography-tandem Mass Spectrometry were utilized to characterize the collected substrates. The current study investigates the (1) chemical characteristics of PM2.5, (2) source apportionment using positive matrix factorization (PMF), and (3) relationship between sources and the dithiothreitol (DTT) assay during the two sampling periods. A mean PM2.5 concentration of 19.3 µg/m3 was observed along the entire sampling route. The ratio of water-soluble to organic carbon implies that secondary aerosol formation is dominant. The result of methanesulfonic acid (MSA) suggests the contribution of a marine-oriented biogenic source of PM2.5. The PMF source apportionment model showed six source categories with reasonably stable profiles: 1) sulfate-rich, 2) MSA-rich, 3) nitrate-rich, 4) secondary organic, 5) continental, and 6) biomass burning sources. The PMF showed three strong events (i.e., long-range transport, mixed (ocean and long-range stay), and domestic origin events) in the contributions of sources, as well as a dependence on wind transport. Higher associations with DTT oxidative potential normalized to PM2.5 mass concentration (DTT-OPm) related to long-range transport, hence, confirming the impacts of the highest intrinsic oxidative potential.

Synthesis of CH3I-quaternized polypropylene nonwoven fiber grafted with imidazole (PP-g-Vim) to adsorb vapor phase ammonia.

Ammonia in gas phase has an unpleasant smell and is hazardous to human health. Though activated carbon has been widely used as a representative adsorbent, it is significantly vulnerable to humidity. In the study, a nonwoven fibrous polypropylene polymer was synthesized using a photo-graft reaction with imidazole followed by quaternization with CH3I. The time of each reaction was optimized for the maximum adsorption. The FT-IR confirmed that 1-vinyl imidazole (Vim) and methyl group (-CH3) were successfully introduced into PP fibers. The Langmuir isotherm characterized that the adsorption capacity was 44.84 mg NO3-N g-1. The adsorption intensity, 1/n, by Freundlich adsorption isotherm was 0.41 indicating that the adsorption of NO3-N onto PP-g-Vim-CH3I was favorable at the studied conditions. In the gas phase, maximum adsorption of was calculated to be 40 ±â€¯0.69 mg NH3 g-1 by BET model. Though the adsorption amount decreased by 2.5 times as the temperature increased from 15 °C to 45 °C, the amounts and rates of adsorption were not influenced by humidity. In conclusion, the synthesized PP-g-Vim-CH3I was able to ammonia in the gas phase at a range of humidity.