Subway trains with air cleaners have been newly deployed in the Seoul Metro system. The purpose of this study was to determine differences regarding in-cabin particulate matter with respect to concentrations less than 10 um (PM10) and 2.5 um (PM2.5) through the operation of air cleaners in subway trains. One subway train newly installed with in-cabin air cleaners on Seoul Metro Line number 2 was chosen monitoring in 2020. In-cabin air cleaners were turned-on at both front and back areas while those in the middle area were turned-off while the train was running. In-cabin PM10 and PM2.5 concentrations were measured in each area using a real-time aerosol monitor. Average in-cabin PM10 concentrations were statistically significantly lower (by 15%) in areas with air cleaners turned-on (43.8±12.1 μg/m3) compared to those areas where the air cleaners were turned-off (51.4±15.0 μg/m3). Average incabin PM2.5 concentrations were significantly lower (by 14%) in areas with air cleaners turned on (33.7±12.2 μg/m3) compared to those areas where air cleaners were turned-off (39.2± 14.4 μg/m3). In-cabin PM10 and PM2.5 concentrations ratios were similar regardless of area with air cleaners turned-on or turned-off. The in-cabin PM10 and PM2.5 concentrations were not associated with commute time. Use of air cleaners in subway trains effected reductions in in-cabin PM10 and PM2.5 concentrations.

This study, conducted from April to May 2004 in the metropolitan and surrounding areas of Seoul, Korea, was performed to show the relationship between indoor and outdoor levels of PM10 and PM2.5 concentrations in 14 residential houses. In addition, indoor/outdoor ratios of PM10, PM2.5 concentrations were calculated. The relationship between the PM10, PM2.5 concentrations and respiratory symptoms by self recording questionnaire of 14 houses was investigated. In conclusion, although the results of this study failed to establish the relationship between PM10, PM2.5 concentrations and respiratory symptoms among residents, the levels of indoor PM2.5 were significantly higher than those of outdoor levels. The indoor PM10, PM2.5 concentrations were increased by the amount of time spent of residents. Further research should be directed to establish the relationship between PM10, PM2.5 concentration and respiratory symptoms.

This research investigated the characteristics of PM10 and PM2.5 concentrations at the main subway stations in Busan. Annual mean PM10 concentrations at the Seomyeon 1- waiting room and platform were 51.3 ㎍/㎥ and 47.5 ㎍/㎥ , respectively, and the annual PM2.5 concentration at the Seomyeon 1- platform was 28.8 ㎍/㎥ . PM2.5/PM10 ratio at Seomyeon 1-platform and Dongnae station were 0.58 and 0.53, respectively. Diurnal variation of PM10 concentration at subway stations in Busan was categorized into four types, depending on the number of peaks and the times at which the peaks occurred. Unlike the areas outside of the subway stations which reported maximum PM10 concentration mostly in spring across the entire locations, the interiors of the subway stations reported the maximum PM10 concentration in spring, winter, and even summer, depending on their location. PM10 concentration was highest on Saturday and lowest on Sunday. The numbers of days when PM10 concentration exceeded 100 ㎍/㎥ and 80 ㎍/㎥ per day over the last three years at the subway stations in Busan were 36 and 239, respectively. The findings of this research are expected to enhace the understanding of the fine particle characteristics at subway stations in Busan and be useful for developing a strategy for controlling urban indoor air quality.

This study investigates weekday/weekend characteristics of PM10 and PM2.5 concentration and metallic elements in Busan in the springtime of 2013. PM10 concentration on weekday/weekend were 77.54 and 67.28 ㎍/㎥, respectively. And PM2.5 concentration on weekday/weekend were 57.81 and 43.83 ㎍/㎥, respectively. Also, PM2.5/PM10 concentration ratio on weekdays/weekend was 0.75 and 0.65, respectively. The contribution rates of Na to total metallic elements in PM10 on weekday/weekend were 38.3% and 38.9%, respectively. It would be useful in control effectively with management of urban fine particle to understand characteristics of fine particle concentration on weekday/weekend.

Ambient particulate matters(PM10 and PM2.5) were investigated at GNTECH university in Jinju city. Samples were collected using a dichotomous sampler(series 240, Andersen Corp.) and a TEOM(Tapered Element Oscillating Microbalance) monitor period from November 2012 to October 2013. For the dichotomous sampler measurements, daily 24-h integrated PM2.5 and PM10–2.5 ambient air samples were collected at a total flow rate of 16.7 L /min. For the TEOM monitor measurements, daily 1-h integrated PM10 ambient air samples were collected at a flow rate of 16.7 L /min. The annual average concentrations of PM10-2.5 and PM2.5 by a dichotomous sampler were 10.0±6.1 μg/m3 and 22.6±9.3 μg/m3, respectively. And PM10 concentration by dichotomous sampler were similar to TEOM monitor by 32.7±12.9 μg/m3 and 31.7±11.3 μg/m3, respectively. And good correlation (R2=0.964) between the two methods was observed. The annual average of PM2.5/PM10 ratio was 0.70±0.12.

The study investigates weekday/weekend characteristics of PM10 and PM2.5 concentrations and meteorological elements in Busan. The PM10 concentration is highest on Wednesday and Thursday, and lowest on Sunday. On the other hand, the PM2.5 concentration is highest on Wednesday and lowest on Sunday. The location where concentrations of weekdays and weekend differ the most is Hwakjang-dong, the industrial area, and where they differ the least is Gijang-up and Joa-dong, the residential area. Fine particle concentration in the industrial area was consistent at dawn and in the morning, but varied in the afternoon and at night. The visibility of Sunday was 0.49 km higher than that of weekdays, and the solar radiation of Sunday was 0.11 MJ/㎡ higher than that of weekdays. These results indicate that the concentration of fine particles had influence on the change of visibility and solar radiation.

This study analyzes the chemical composition of metallic elements and water-soluble ions in PM10 and PM2.5. PM10 and PM2.5 concentrations in Busan during 2010-2012 were 97.2±67.5 and 67.5±32.8 ㎍/㎥, respectively, and the mean PM2.5/PM10 concentration ratio was 0.73. The contribution rate of water-soluble ions to PM10 ranged from 29.0% to 58.6%(a mean of 38.6%) and that to PM2.5 ranged from 33.9% to 58.4%(a mean of 43.1%). The contribution rate of sea salt to PM10 was 13.9% for 2011 and 9.7% for 2012, while that to PM2.5 was 17.4% for 2011 and 10.1% for 2012. PM10 concentration during Asian dust events was 334.3 ㎍/㎥ and 113.3 ㎍/㎥ during non-Asian dust events, and the PM10 concentration ratio of Asian Dust/Non Asian dust was 2.95. On the other hand, the PM2.5 concentration in Asian dust was 157.4 ㎍/㎥ and 83.2㎍/㎥ in Non Asian dust, and the PM2.5 concentration ratio of Asian Dust/Non Asian dust was 1.89, which was lower than that of PM10.

This study introduces a novel approach to the differentiation of two phenomena, Asian Dust and haze, which are extremely difficult to distinguish based solely on comparisons of PM10 concentration, through use of the Optical Particle Counter (OPC), which simultaneously generates PM10, PM2.5 and PM1.0 concentration. In the case of Asian Dust, PM10 concentration rose to the exclusion of PM2.5 and PM1.0 concentration. The relative ratios of PM2.5 and PM1.0 concentration versus PM10 concentration were below 40%, which is consistent with the conclusion that Asian Dust, as a prime example of the coarse-particle phenomenon, only impacts PM10 concentration, not PM2.5 and PM1.0 concentration. In contrast, PM10, PM2.5 and PM1.0 concentration simultaneously increased with haze. The relative ratios of PM2.5 and PM1.0 concentration versus PM10 concentration were generally above 70%. In this case, PM1.0 concentration varies because a haze event consists of secondary aerosol in the fine-mode, and the relative ratios of PM10 and PM2.5 concentration remain intact as these values already subsume PM1.0 concentration. The sequential shift of the peaks in PM10, PM2.5 and PM1.0 concentrations also serve to individually track the transport of coarse-mode versus fine-mode aerosols. The distinction in the relative ratios of PM2.5 and PM1.0 concentration versus PM10 concentration in an Asian Dust versus a haze event, when collected on a national or global scale using OPC monitoring networks, provides realistic information on outbreaks and transport of Asian Dust and haze.

In order to investigate the variations and corelation among PM10, PM2.5 and PM1 concentrations, the hourly concentrations of each particle sizes of 300 ηm to 20 μm at a city, Gangneung in the eastern mountainous coast of Korean peninsula have been measured by GRIMM aerosol sampler-1107 from March 7 to 17, 2004. Before the influence of the Yellow Dust event from China toward the city, PM10, PM2.5 and PM1 concentrations near the ground of the city were very low less than 35.97 μg/m3, 22.33 μg/m3 and 16.77 μg/m3, with little variations. Under the partial influence of the dust transport from the China on March 9, they increased to 87.08 μg/m3, 56.55 μg/m3 and 51.62 μg/m3. PM10 concentration was 1.5 times higher than PM2.5 and 1.85 times higher than PM1. Ratio of (PM10-PM2.5)/PM2.5 had a maximum value of 1.49 with an averaged 0.5 and one of (PM2.5-PM1)/PM1 had a maximum value of 0.4 with an averaged 0.25. PM10 and PM2.5 concentrations were largely influenced by particles smaller than 2.5 μm and 1 μm particle sizes, respectively. During the dust event from the afternoon of March 10 until 1200 LST, March 14, PM10, PM2.5 and PM1 concentrations reached 343.53 μg/m3, 105 μg/m3 and 60 μg/m3, indicating the PM10 concentration being 3.3 times higher than PM2.5 and 5.97 times higher than PM1. Ratio of (PM10-PM2.5)/PM2.5 had a maximum value of 7.82 with an averaged 3.5 and one of (PM2.5-PM1)/PM1 had a maximum value of 2.8 with an averaged 1.5, showing PM10 and PM2.5 concentrations largely influenced by particles greater than 2.5 μm and 1 μm particle sizes, respectively. After the dust event, the most of PM concentrations became below 100 μg/m3, except of 0900LST, March 15, showing the gradual decrease of their concentrations. Ratio of (PM10-PM2.5)/PM2.5 had a maximum value of 3.75 with an averaged 1.6 and one of (PM2.5-PM1)/PM1 had a maximum value of 1.5 with an averaged 0.8, showing the PM10 concentration largely influenced by corse particles than 2.5 μm and the PM2.5 by fine particles smaller than 1 μm, respectively. Before the dust event, correlation coefficients between PM10, PM2.5 and PM1 were 0.89, 0.99 and 0.82, respectively, and during the dust event, the coefficients were 0.71, 0.94 and 0.44. After the dust event, the coefficients were 0.90, 0.99 and 0.85. For whole period, the coefficients were 0.54, 0.95 and 0.28, respectively.