Five Year Trends of Particulate Matter Concentrations in Korean Regions (2015–2019): When to Ventilate?

Abstract

Indoor air quality becomes more critical as people stay indoors longer, particularly children and the elderly who are vulnerable to air pollution. Natural ventilation has been recognized as the most economical and effective means of improving indoor air quality, but its benefit is questionable when the external air quality is unacceptable. Such risk-risk tradeoffs would require evidence-based guidelines for households and policymakers, but there is a lack of research that examines spatiotemporal long-term air quality trends, leaving us unclear on when to ventilate. This study aims to suggest the appropriate time for ventilation by analyzing the hourly and quarterly concentrations of particulate matter (PM)10 and PM2.5 in seven metropolitan cities and Jeju island in South Korea from January 2015 to September 2019. Both areas’ PM levels decreased until 2018 and rebounded in 2019 but are consistently higher in spring and winter. Overall, the average concentrations of PM10 and PM2.5 peaked in the morning, declined in the afternoon, and rebounded in the evening, but the second peak was more pronounced for PM2.5. This study may suggest ventilation in the afternoon (2–6pm) instead of the morning or late evening, but substantial differences across the regions by season encourage intervention strategies tailored to regional characteristics.

Diurnal and Seasonal Variations of Particulate Matter Concentrations in the Urban Forests of Saetgang Ecological Park in Seoul, Korea

“…Moreover, springsummer seasons may also increase the PM concentrations due to stationary air masses, intense secondary aerosol formation, and increased occurrences of forest fires [28][29][30][31][32][33][34][35]. In Korea, the PM concentrations are lower in summer than in other seasons because of active mixing by turbulent flow, such as rains and typhoons [36]. At the national level, a period of high PM concentrations due to large air currents appears as a seasonal feature; however, as the emissions of roads and automobiles, which are major pollutants in cities, are relatively constant throughout the year, the seasonal characteristics of PM in urban forests can be identified.…”

Indoor concentrations of particulate matter 2.5 in a pediatric emergency service

“…Its respirable fraction (2.5 μm) is able to reach the small airway caliber and promote alveolar deposition; besides, it is associated to the higher prevalence of several respiratory, cardiovascular and metabolic diseases conditions. 10 Therefore, we proposed to evaluate if air quality in the waiting room of an emergency pediatric service is influenced by the number of people circulating in the room.…”

Real-Time Low-Cost Personal Monitoring for Exposure to PM2.5 among Asthmatic Children: Opportunities and Challenges

“…Most of these studies emphasize the cumulative effects of PM exposure over an extended period time, which emphasizes the importance of personalized continuous monitoring and the need for control of indoor and outdoor PM levels in surrounding atmosphere of individuals who experience relevant symptoms [5]. However, in many countries, air quality management and health impact evaluation are still based on ambient air monitoring using the traditional stationbased system [6][7][8]. This monitoring system is typically equipped with high-performance and expensive sensors with strong calibration stability, producing accurate data on outdoor air quality measurements for surrounding environments [9].…”

“…Therefore, they are unable to indicate the true level of exposure for individuals, depending on their lifestyle, mobility and actual location. Most people nowadays tend to stay indoors for longer periods of time and the impact of indoor PM on their health is far more important than that of outdoor air pollution, especially due to its long-term exposure at low concentration levels [7]. Thus, personalized PM monitoring based on real-time locations has been proven itself to be a better alternative for exposure assessment and is being actively researched due to the advances in IoT (Internet of Things) devices and networks [13].…”