Changes in NO2 Concentration from Major Cities and Provinces in Korea: A Case Study from 1998 to 2003

Abstract

In this paper, the spatio-temporal distribution characteristics of nitrogen dioxide (NO 2) were investigated using data obtained routinely from air quality monitoring stations located in seven major cities and nine provinces in Korea for the period 1998 to 2003. The results indicate that annual trends in NO 2 concentrations generally reflect changes in environmental conditions, while exhibiting cyclic and systematic patterns across seasons. Its wintertime concentrations were most prominent, with concentrations decreasing gradually across spring, fall, and summer. If concentration patterns are examined among different cities and/or provinces, the highest mean values were found from the Capital city, Seoul (34.7 ppb) and the surrounding province, Gyunggi (30.2 ppb). In contrast, remarkably reduced NO 2 concentrations were seen in such regions as the remote island, Jeju and Jeonnam province with mean values of 17.5 and 16.5 ppb, respectively. The overall results of our study indicate that there are strong geographical gradients in NO 2 distributions to exhibit strongly polluted patterns consistently in densely populated urban areas (e.g., major city), compared to large rural areas (e.g., province).

Seasonal variation of Nitrogen dioxide and particulate matter in the capital City (City of Tshwane) of South Africa and its compliance to South African Air Quality Standards

“…This process involves decreased photochemical interactions between NO2 and hydroxyl (OH) radicals, forming nitric acid (HNO3). Several ambient air quality monitoring studies have also observed this pattern (Nguyen et al, 2006;Al Katheeri et al, 2012).…”

Air Quality Trends in Metropolitan Zones in Veracruz, México

“…When stratified in periods according the EURO standards, the ratio NO 2 /NOx increased in 7/9 cities, NO/NO 2 ratio decreased in 8/9 cities and a permanent inversion in NO/NO 2 ratio was observed to occur in 2003 in 5/9 cities. Nguyen and Kim analyzed the nitrogen dioxide (NO 2 ) in cities and major provinces in Korea from 1998 to 2003, finding that concentrations of this gas reflected changes due to environmental conditions and seasonal patterns, where the highest levels were observed in winter, with decreasing patterns during spring, autumn and summer [8]. These observed levels of NO 2 pollution were spatially distributed in greater numbers over highly populated urban areas with peaked values from 38 to 56 μg/m 3 (with a single case at 75 μg/m 3 ) compared with rural areas, which showed values from 38 to 47 μg/m 3 .…”