• Journal of Korean Society for Atmospheric Environment
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• v.13 no.6
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• pp.415-426
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• 1997

Some arguments have been about over the representativeness of government-run air quality monitoring stations among scholars and non-governmental organizations (NGOs). However, it is not a simple problem to move monitoring stations because of continuity of data and high cost. So it is necessary to complement the monitoring data if it do not represent the ambient air quality properly. The purpose of this study was to evaluate the representativeness of some monitoring stations using passive $NO_2$ samplers and to find a complementary method from linear regression. Two stations were chosen for the evaluation: Shinlim Station was one of the most controversial stations in Seoul and Banpo Station had the best reputation. Air qualities were surveyed at seven points around each monitoring station with consideration of land use and distance. The ratios of the average $NO_2$ levels of the areas to these at the monitoring stations were 1.59 for Shinlim Station and 1.03 for Banpo Station. The differences between the average $NO_2$ levels and those at the monitoring stations were 10.75 ppb for Shilim Station and 0.34 ppb for Banpo Station. The correlation coefficients between the two levels were 0.7668 for Shinlim and 0.7662 for Banpo. The average coefficients of determination $(R^2)$ were 0.61 for Shinlim and 0.61 for Banpo. The Shinlim Station could not represent the air quality of Shinlim-Dong good because it is located in a green area at an outskirt of Shinlim-Dong. But the Banpo Station located in a central residential area of Banpo-Dong showed a fair representativeness. However, air quality turned out to be different with land use such as residential area, green area or road: the air quality data from a monitoring station located at a certain land use should not be interpreted as representing the air quality at any sites around the station. Equations to predict the average $NO_2$ levels of each area from the data from the monitoring stations were presented based on linear regression.

• Journal of Environmental Impact Assessment
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• v.5 no.1
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• pp.79-85
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• 1996

Simultaneous monitoring in many locations is necessary to evaluate the air quality and analyze future trend of a city, For this purpose, it is essential to install air pollution monitoring network. The first automatic air pollution monitoring network was introduced Seoul in 1973. As of 1995, 20 monitoring stations are now in operation. Concerning the management of the air pollution monitoring network, there was some argument among the relavant scholars, non-governmental organization(NGO) and the government organization. So far, there was no extensive evaluation and analysis about the network. The purpose of this study was to evaluate the representativeness of air quality monitoring network through actual measurement of the concentration of the air pollutant. The concentration of NOx was extensively measured widely in Seoul area three times using the TEA simple measuring technique. Even the judgement level for the area representativeness was lowered to 80%, Ssangmun-dong monitoring station tend to overestimate the pollutant concentration of the covered area. While, Sinlimdong monitoring station tend to underestimate the pollutant concentration of the covered area.

• Journal of Environmental Impact Assessment
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• v.20 no.1
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• pp.49-59
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• 2011

The results of comparing $PM_{10}$ concentration between 'Namsan' and 'Yongsan-gu' air quality monitoring stations show similar values with averaged concentration in the whole Seoul. The correlation factors in both sites were 0.865, 0.828 in 2005, 2006, respectively. For 'Bukhansan' and 'Gangbuk-gu' air quality monitoring stations, different from the results mentioned above, they showed clear differences as altitude changes. PM10 concentration in 'Bukhansan' monitoring stations was 10 ${\mu}g/m^3$ lower than 'Gangbuk-gu' monitoring station which is located near the ground. Also, averaged PM10 concentration in 'Bukhansan' and 'Gangbuk-gu' monitoring stations was lower than that in the whole Seoul. When comparing $NO_2$ concentration between 'Namsan' and 'Yongsan-gu' monitoring stations, $NO_2$ concentration in 'Namsan' monitoring station was lower than 'Yongsan-gu' monitoring station. For $NO_2$ concentration in 'Bukhansan', 'Gangbuk-gu' and 'the whole Seoul', there were the same pattern in 'Gangbuk-gu' and the 'the whole Seoul' and low values in 'Bukhansan' monitoring station. The correlation factors of $NO_2$ concentration in 'Bukhansan' and 'Gangbukgu' was 0.525, 0.549 in 2005, 2006, respectively, which stands for low correlationship.

• Journal of Environmental Science International
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• v.25 no.5
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• pp.673-681
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• 2016

The adequacy of urban air quality monitoring networks in the largest metropolitan city, Seoul was evaluated using multivariate analysis for $SO_2$, $NO_2$, CO, PM10, and $O_3$. Through cluster analysis for 5 air pollutants concentrations, existing monitoring stations are seen to be clustered mostly by geographical locations of the eight zones in Seoul. And the stations included in the same cluster are redundantly monitoring air pollutants exhibiting similar atmospheric behavior, thus it can be seen that they are being operated inefficiently. Because monitoring stations groups representing redudancy were different depending on measurement items and several pollutants are being measured at the same time in each air monitoring station, it is seemed to be not easy to integrate or transmigrate stations. But it may be proposed as follows : the redundant stations can be integrated or transmigrated based on ozone of which measures are increasing in recent years and alternatively the remaining pollutants other than the pollutant exhibiting similar atmospheric behavior with nearby station's can be measured. So it is considered to be able to operate air quality monitoring networks effectively and economically in order to improve air quality.

• Journal of Environmental Science International
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• v.18 no.9
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• pp.941-952
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• 2009

The urban microscale wind field around the air quality monitoring station was investigated in order to check how a building complex influences it. For this study as the high density areas Jwa-dong and Yeonsan-dong monitoring sites in Busan were chosen. As the direction of inflow which is perpendicular to the building of the monitoring station was expected to cause the considerable variation of the wind field, that direction was selected. The model Envi-met was used as the diagnostic numerical model for this study. It is suitable for this investigation because Envi-met has the microscale resolution. After simulating it, on the leeward side around a building complex the decrease of flow velocity and some of vortexes or circulation area were discovered. In addition, on the edge of the top at the building and at the back of the building the upward flow was developed. If the sampling hole of monitoring site were located in this upward flow, it would be under the influence of upward flow from the near street.

• Journal of Environmental Science International
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• v.20 no.1
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• pp.81-91
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• 2011

Air quality monitoring networks are very important facilities to manage urban air pollution control and to set up an environmental policy. Since air quality monitoring network of Daegu was allocated from 1980s to mid-90s, there is need to reevaluate it and relocated its site. This study was evaluated the position of Daegu air quality monitoring station by unit environmental sensitivity index, grid emission rate, CAI (Comprehensive Air-quality Index) point. The investigation domain covered an area of 16 $\times$ 24 km centered at the metropolitan area of Daegu with grid spacing of 2 km. The location of alternative air quality monitoring networks was selected through optimization and quintiles analysis of total score. The result showed that all things considered, new air quality monitoring network need to install grid numbers 10, 28, 36, 37, 46. We also recommand three scenarios of alternative air quality monitoring network when considering unit environmental sensitivity index, emission rate and CAI point.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.4
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• pp.405-420
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• 2006

This study was conducted to understand the change of spatial environmental factors including populations, air pollution source and land-use in Busan, during the period of 1995 and 2004. Firstly, the grids (5 km $\times$ 5 km) were divided using the TM coordinates of Busan and the statistical data of populations and land-use were marked on each grid during studying period. Secondly, the SO$_2$, NO$_2$ and O$_3$ concentrations of areas where air quality monitoring station was not established were estimated on the basis of these air pollutants measured at close air quality monitoring station by kriging method. In order to understand spatial change of air pollution and to investigate duplication and reduction of existing stations, semivariogram, correlation and cluster analysis were carried out. This study showed that the population increased in 2004 only on 8 grids compared to in 1995. The spatial change of SO$_2$, NO$_2$ and O$_3$ was investigated by semivariogram in Busan area. As the results of semivariogram, the spatial change of 502 become smaller and simpler, while that of NO2,03 become larger and more complex in 2004 than in 1995, According to the result of correlation and cluster analysis, the reduction of measurement item or the relocation of air quality monitoring station can be needed in the high dense grid area.

• Proceedings of the IEEK Conference
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• 2009.05a
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• pp.48-50
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• 2009

This paper presents an IAQ(Indoor Air Quality) Monitoring System using equipments for measurement of fine Particle($PM1{\sim}PM10$), $CO_2$, VOCs(Volatile Organic Compounds), temperature and humidity for IAQ monitoring of subway station which millions of people use a day. The necessity of IAQ monitoring system is getting increased for more effective subway station monitoring in line with the recent government's regulation for IAQ is reinforcing. Subway Station is an unusual case. The structure of subway station is closed and complicated. Therefore when data of equipments are transferred, transmission error can happen occasionally. To prevent transmission error, an IAQ Monitoring System is needed the appropriate position and selection of equipments or sensor module. In addition IT(Information Technology) can be utilized like "WiBro(Wireless Broadband)" and "GateWay" for facilitate movement of data and construction of IAQ monitoring system of subway station.

• Journal of Korean Society for Atmospheric Environment
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• v.30 no.3
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• pp.233-244
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• 2014

The objective of this study was to explore the characteristics of concentration of indoor air pollutants, such as $PM_{10}$, $CO_2$, and $NO_2$, measured by tele-monitoring system in a Seoul Metropolitan underground railway station from January 1, 2008 to December 31, 2012. The annual average concentration of indoor air pollutants actually varied over a wide range and was found to exhibit marked variation with time and measurement sites (tunnel inlet, platform, and concourse). After installing platform screen doors, the average $PM_{10}$ concentration on platform and concourse was decreased by 43.8% and 31.2%, respectively during the study periods. The relationship between the concentration of $PM_{10}$ and meteorological parameters (relative humidity and rainfall) or the Asian dust events was regarded as statistically significant. The correlations between the number of boarding/alighting passengers and $PM_{10}$, $CO_2$, and $NO_2$ were calculated. A p-value of less than 0.01 was regarded as significant except $NO_2$. The I/O ratio of $PM_{10}$ concentration was elevated after a congested time (about 08:00 am). The average I/O ratios of $NO_2$ were observed in concourse and platform on 03:00 am with $1.76{\pm}0.91$ and $1.50{\pm}0.51$, respectively. The average daily variation of standard excess rate of $PM_{10}$ and $NO_2$ concentration in concourse and platform was investigated. The highest standard excess rate was observed on 21:00 (09:00 pm).

• Particle and aerosol research
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• v.16 no.2
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• pp.31-47
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• 2020

Although interest in air quality has increased due to the frequent occurrence of high-concentration fine particulate matter recently, the official fine particulate matter measuring network has failed to provide spatial detailed air quality information. This is because current measurement equipment has a high cost of installation and maintenance, which limits the composition of the measuring network at high resolution. To compensate for the limitations of the current official measuring network, this study constructed a spatial high density measuring network using the fine particulate matter simple measuring device developed by Observer, W-Station. W-Station installed 48 units on Jeju Island and measured PM_2.5 for six months. The data collected in W-Station were corrected by applying the first regression equation for each section, and these measurements were compared and analyzed based on the official measurements installed in Jeju Island. As a result, the time series of PM_2.5 concentrations measured in W-Station showed concentration characteristics similar to those of the environmental pollution measuring network. In particular, the results of comparing the measurements of W-Station within a 2 km radius of the reference station and the reference station showed that the coefficient of determination (R²) was 0.79, 0.81, 0.67, respectively. In addition, for W-Station within a 1 km radius, the coefficient of determination was 0.85, 0.82, 0.68, respectively, showing slightly higher correlation. In addition, the local concentration deviation of some regions could be confirmed through 48 high density measuring networks. These results show that if a network of measurements is constructed with adequate spatial distribution using a number of simple meters with a certain degree of proven performance, the measurements are effective in monitoring local air quality and can be fully utilized to supplement or replace formal measurements.