According to the report compiled by the United Nations Environment Program (UNEP) together with the North's environment ministry, the average sulfur dioxide concentration in Pyongyang stood at 0.009 parts per million (ppm) in 2008, higher than the 0.006 ppm measured in Seoul the same year.
Sulfur dioxide, which is produced when burning fossil fuels, can cause respiratory problems and exacerbate conditions such as asthma and bronchitis.
The pollution in the atmosphere has been attributed to an increase in coal-fired plants in Pyongyang as well as the rising household consumption of coal, according to the report.
Other factors such as the quality of water and the rate at which forests are declining were also found to be at severe levels.
Pyongyang (AP-Yonhap file photo)
A lack of sewage treatment facilities has left the Taedong River, which flows through Pyongyang, with an average chemical oxygen demand of 2.15 ppm in 2008, falling behind the environmental standard of 3 ppm, according to the report.
The river's average coliform count stood at more than three times the standard amount recommended for the potentially hazardous bacteria, the report added.
North Korea's forested land area has also been declining rapidly, as the area of timber forests was reduced by nearly 6,000 square kilometers between 1990 and 2002, due largely to soil erosion and the country's push to convert forests into agricultural land, the report showed.
In response to its findings, the UNEP report said the North should set concrete environmental standards and should implement eco-friendly technologies to protect the environment and promote sustainable development.