Asian Journal of Atmospheric Environment最新文献

Microplastics are a very complex, diverse, and persistent contaminant class in aquatic ecosystems, providing significant challenges for scientists in developing analytical methodologies, fate and transport models, identification of exposure routes, and toxicological risk evaluation are all key difficulties for scientists. Despite a considerable and developing body of thought concerning the effects of microplastics on aquatic species, nothing is known about the effects of microplastics on humans. Microplastics have been found in food all across the world. As a result, human exposure to microplastics through tainted food is unavoidable, possibly creating health risks. In recent years, a major research effort has added to our understanding, but there is an urgent need to simplify and integrate the findings. This review focuses on the effects of microplastics as well as methods for decomposing plastics without creating microplastic particles. Among the various plastic breakdown methods, employing microorganisms and nanotechnology might be a long-term solution in preventing environmental microplastic contamination.

In recent years, endotoxins have received considerable attention as substances associated with allergic diseases. Endotoxins are cell wall components of gram-negative bacteria that are widely present in the living environment. Endotoxin concentrations are particularly high in environments where animals are housed. However, while the status of endotoxin concentrations in the general environment is becoming clearer, there remains a scarcity of studies in environments with potentially higher concentrations.

In this study, we measured indoor endotoxin concentrations in buildings in Japan that are strongly associated with horses. The target buildings include a “Magariya,” an old Japanese house, an accommodation facility connected to a horse stable, and a stable specifically for thoroughbreds. Air and dust samples were collected at these measurement targets and analyzed for air and dust concentrations.

Airborne concentrations were higher in buildings with horses present than in buildings without horses, and the presence/absence of horses is thought to have a significant effect on the airborne concentration of endotoxin. Additionally, as the density of horses increases, endotoxin concentrations also tend to increase. Dust concentration had different values in different rooms even in the same building. These results suggest that dust concentrations may be affected by floor materials, frequency of cleaning, and frequency of human traffic from areas of high concentrations. Endotoxin concentrations were high in the stable during the work because of the replacement of the dried straw in the stalls and the removal of horse excrement. These results are expected to be useful in controlling endotoxin concentrations in indoor environments of various building types.

The emission sources of fine particulate matter (PM_2.5) have not yet been fully identified in Ho Chi Minh City (HCMC), Vietnam, presenting difficulties to authorities in controlling air pollution efficiently. To address this issue, this study explores the source apportionment of PM_2.5 by the positive matrix factorization (PMF) model and identifies potential regional sources through the weighted concentration-weighted trajectory (WCWT) model based on the field observation data of PM_2.5 in HCMC. 24-h PM_2.5 samples were collected in central HCMC for a year (September 2019–August 2020). Herein, inductively coupled plasma mass spectroscopy was used to analyze trace elements, in addition to identifying PM_2.5 mass and other chemical species, such as water-soluble ions and carbonaceous species, reported in our former study. The PMF results showed that PM_2.5 in HCMC was dominated by anthropogenic-rich sources comprising biomass burning, coal combustion, transportation, and crustal origins (36.4% of PM_2.5 mass), followed by secondary ammonium sulfate (18.4%), sea salt (13.7%), road dust (9.6%), and coal and crude oil combustion (9.4%). WCWT results suggested that the geological sources of PM_2.5 were mainly from local areas and scattered to the northeast/southwest of HCMC. In addition, the long-range transport of PM_2.5 from surrounding countries was revealed during the assembly restriction and lockdown period in 2020.

Graphical Abstract

Paju City is located in the northwest of Gyeonggi-do, and its chemical emissions in 2020 were 1,287,917 kg, the 4th highest in Gyeonggi-do. In particular, the Munsan High-Tech Industrial Complex in Paju has LCD manufacturing plants and partner companies distributed in groups, and the volatile organic compounds used by these companies are causing many problems, such as causing bad odors, to the local community. In this sense, real-time analyzing equipment (proton-transfer-reaction time-of-flight mass spectrometry) was mounted on a vehicle for this study to look into the air quality around VOCs-using companies inside the High-tech Industrial Complex in Munsan, Paju from October 19 to October 21, 2020.

According to measurement results, toluene was detected the most at 25.7 ppb, followed by carbon tetrachloride (17.6 ppb), ethylbenzene (17.2 ppb), and xylene (8.5 ppb), which demonstrates that there is a need to control these substances to resolve the issue with VOCs in the region. In particular, benzene designated as the air quality standard was detected at 1.0 ppb in some sites, which is below the threshold (1.5 ppb). However, it was detected at 2.1 to 4.4 ppb, exceeding the threshold in most sites. Thus, continuous monitoring is expected to keep VOCs under control in Paju Industrial Complex down the road, using real-time measuring equipment.

The feasibility of a novel type of moss (Parkortanso No. 1 synthesized from Racomitrium japonicum, Dozy and Molk) to capture CO₂ in urban areas was demonstrated. The effects of light intensity (500, 1000, and 1500 µmol/m².s), ambient temperature (10 °C, 25 °C, and 35 °C), age (1-year-old and 3 years old), and leaf color (bright and dark green) on the CO₂ removal caused by the moss concerned were investigated. It was determined that stronger light intensity resulted in higher CO₂ removal by the target moss. The moss showed the best CO₂ capture at 25 °C, while the CO₂-capturing capacities declined when the ambient temperatures were 10 °C and 35 °C. Three years old bright green moss was found to have higher CO₂-capturing capacity than 1 year old. Similarly, bright green moss exhibited the best CO₂ uptake out of the mosses concerned. The highest net CO₂ emission of the moss was − 1.94 ± 0.72 kgCO₂/m².year, which was comparable to other moss and plant species. Consequently, the bright green and old Parkortanso No. 1 moss are recommended for a green roof application in terms of CO₂ capture.

Graphical Abstract

This study examines the change in rice yield due to ozone exposure in South Korea using extended air quality monitoring data from 2000 onwards. Notably, the maximum daily 8-h average O₃ (MDA8O3) showed a substantial annual increase of 1 part per billion by volume (ppbv) from 1990 to 2021. AOT40 (accumulated dose of ozone over a threshold of 40 ppb) levels exceeded set thresholds in the early 2010s, and the M7 (mean 7-h ozone mixing ratio) index exhibited a parallel pattern, with a more pronounced increase than the AOT40 during the same period. Spatial variations of AOT40 and M7 metrics have been assessed annually across South Korea since 2000. Both metrics displayed spatial disparities, with higher values in western regions and lower values in the east. In particular, Dangjin and Seosan counties in Chungnam province experienced the greatest rice yield loss due to extensive rice cultivation area and high ozone exposure metrics. The quantified yield loss due to AOT40 increased from 127,000 in 2000 to 230,000 tonnes in 2021 with an increasing rate of 6500 tonnes per year. M7 indicated a rise in yield loss of 3500 tonnes per year, with yield losses growing from 32,000 in 2000 to 92,000 tonnes in 2021. Despite M7’s lower loss, it demonstrated a higher percentage increase of 188% over two decades, which was double AOT40’s 81%. While the decline in rice production was mainly linked to shrinking cultivation areas, its productivity was improved. Taking both factors into account, there was an unexplained 3% decrease in production over the same period. This discrepancy was close to the 2.5% rice yield loss attributed to the AOT40 metrics, suggesting that the majority of the additional 3% decline in production, surpassing improvements in productivity, could be attributed to the impacts of ozone exposure. We estimated the annual economic loss due to rice yield loss up to around 0.6 billion US dollars, corresponding to an annual rice production loss of 230,000 tonnes using AOT40. It is important to note that this value is expected to steadily worsen as ozone levels increase. This underscores the urgency of taking swift measures to reduce ozone levels, aiming not only to mitigate future economic losses but also to prevent potential health implications.

Using updated emission inventories can enhance the accuracy of air quality forecast models. Given China’s rapid economic growth and Korea’s geographical and meteorological position on the windward side of China, updating China’s emission inventory has become particularly crucial for Korea’s air quality modeling. This study aimed to develop an updated version of China’s Emission Inventory in Comprehensive Regional Emissions for Atmospheric Transport Experiments version 3 for the base year of 2019 (CREATEv3 (YR 2019)). To achieve this goal, we utilized the Chinese emission inventory of CREATEv3 for the base year of 2015 (CREATEv3 (YR 2015)) as a framework to incorporate the latest Chinese emission data from the Multi-resolution Emission Inventory Model for Climate and Air Pollution Research for the base year of 2019 (MEIC COVID-19 (YR 2019)) and update the inventory. The updated China’s annual emissions are now reflected in CREATEv3 (YR 2019), and the amounts are as follows: 132 Tg for CO, 21 Tg for NO_x, 8 Tg for SO₂, 7 Tg for PM_2.5, 9 Tg for NH₃, and 28 Tg for volatile organic compound (VOC). By comparing previous Chinese emission inventories with the updated inventory developed in this study, it was found that SO₂, NO_x, VOC, and NH₃ emissions were decreased. Therefore, using the updated inventory seemingly reduces the impact of China’s fine dust on Korea. By comparing emissions by pollutant and region in China using CREATEv3 (YR 2019), it was found that regions with high emissions of targeted pollutants strongly correlated with major industries operating in those areas. This study is expected to provide insights into China’s emission changes in 2019 and support air quality forecasting.

Among countries that are a part of the Organization for Economic Co-operation and Development, South Korea is the most exposed to PM_2.5. Despite the country having implemented various strategies to limit PM_2.5 emissions, its concentrations are still high enough to pose serious environmental and health concerns. Herein, we monitored various physiochemical properties of PM_2.5 across different regions in South Korea from January 1 to December 31, 2021. Specifically, the study area consisted of the city center, industrial complexes, and suburban areas. Before analyzing dynamics of emissions specific to each site, the Clean Air Policy Support System data for the three areas were compared to elucidate their respective primary emission sources. The particle concentrations for the three areas were 21.8–26.44 µg/m³, with the highest concentrations being observed in March. All the three areas exhibited high ratios of NO₃⁻ across all seasons. The particle number concentrations in the three sites were 1.3–1.5 × 10⁷, and the peak points of the concentrations were different in every site: city center (40 nm), industrial complexes (60 nm), and suburban areas (80 nm). We also conducted potential source contribution function and conditional bivariate probability function analyses. These analyses were conducted to determine the inflow direction of the pollution sources for high PM_2.5 episodes. For the episodes that occurred in spring and winter, there were no differences in the PM_2.5 concentrations between the three sites. Overall, the insights gained from this study offer a framework for developing air-quality management policies in South Korea, specifically in the context of PM_2.5 emissions.

In the region where heat stress has become evident, the elevation of air temperature could reduce yield of heat stress-susceptible crops, such as rice (Oryza sativa L.), which is a major food staple in Asia. In addition to air temperature, atmospheric CO₂ is projected to be elevated in the future. To project rice yield in the future, it is necessary to clarify the responses of rice to concurrent elevations of air temperature and atmospheric CO₂. In the present study, two japonica rice cultivars with different heat tolerance, Hinohikari (sensitive) and Nikomaru (tolerant), were grown in pots inside open-top chambers and exposed to elevated air temperature and/or CO₂. The degrees of increase in the air temperature and CO₂ concentration by the treatments were approximately 1 °C and 120 µmol mol⁻¹ (ppm). The study was conducted in Nagasaki, Japan, where heat stress on rice has become evident. Elevated air temperature significantly decreased both whole-plant growth and grain yield. Elevated CO₂ significantly increased the growth but significantly decreased the yield. The effects of elevated air temperature and elevated CO₂ on growth and yield did not significantly differ between two cultivars. In both cultivars, the main cause of yield reduction by both treatments was reduction in spikelet fertility, which is typical heat stress on rice. The elevated CO₂-induced reduction in spikelet fertility could be explained partially by high-temperature regime during flowering due to acceleration of heading and by increase in canopy temperature via stomatal closure in flag leaves. Because elevated air temperature and elevated CO₂ treatments additively reduced spikelet fertility in both cultivars, concurrent elevations of air temperature and CO₂ caused considerable reduction in grain yield.