In carbon emissions data that Daniel Moran’s research group gathered from 13,000 cities worldwide, Seoul and the population of the surrounding metropolitan area, where about half of South Korea’s 52 million population resides, had extremely high carbon emissions.The city came in No. 1, with an output of 276.1 metric tons of carbon dioxide a year as of 2015, data show.The results were published Thursday in the international science journal Environmental Research Letters.Five other local cities in the country are in the top 500 for carbon footprint, including Busan at No. 50 with an output of 42.3 metric tons of carbon dioxide, Daegu at No. 115, Daejeon at No. 126, Gwangju at No. 132 and Ulsan at No. 155.In terms of carbon footprint per capita, Seoul ranked 200th at 13 kilograms of carbon dioxide per year, while Hong Kong came in first at 34.6, according to data.Seoul and the metropolitan area often see the daily average of air quality hit “extremely bad” levels, with airborne particulate matter categorized as harmful by the World Health Organization, as it can penetrate the respiratory system.According to the National Institute of Environmental Research on Sunday, the country’s average concentration levels of particulate matter last year marked 44 micrograms per cubic meter and 25 for fine dust, two times higher than other advanced cities, including Paris, Los Angeles, London and Tokyo, during the same period.The environment institute announced last year that nearly 35 percent of the country’s particulate matter originates from China, while 9 percent comes from North Korea and the rest stems from within the country.Earlier this year, President Moon Jae-in officially raised concerns over worsening air pollution here originating from China during his talks with Chinese special envoy Yang Jiechi, urging the Chinese government to do more to stop it.By Bak Se-hwan ( sh@heraldcorp.com