The impact of nitrogen oxides emitted from cement manufacturing facilities on the PM 2.5 concentration in the atmosphere

             Cement is an essential material for construction, but cement manufacturing factories are concentrated in areas where the raw materials are produced and the manufacturing process requires a large amount of energy. In Republic of Korea, a total of 50,237 tonnes in 2023 are produced at 13 manufacturing plants composed of 9 cement companies. Among these 13 plants, 6 are located in Gangwon-do Province. The cement production process generates a large amount of pollutants, including nitrogen oxides, sulfur oxides, and fine dust, causing various environmental issues and complaints from local residents in the surrounding areas near by the cement manufacturing factories.

In Republic of Korea, the proportion of using waste materials (especially plastic waste) as an alternative fuel instead of anthracite coal has been increasing recently. Additionally, the nitrogen oxide emission limit for cement manufacturing plants is set at 270 ppm (for facilities installed before 2007), which is much alleviated level than the 70 ppm limit for waste incineration plants (with a capacity of 2 tonnes per hour or more).

             Nitrogen oxides emitted into the atmosphere can act as precursor substances for acid rain, and they can also convert into fine dust (<PM 2.5) through photochemical reactions, potentially affecting the concentration of fine particulate matter in the air. The high concentrations of nitrogen oxides emitted from cement manufacturing facilities can impact the fine dust concentration in Gangwon-do Province, where these facilities are concentrated.

             Therefore, the objectives of this study are as follows: First, to calculate the proportion and amount of waste materials (specifically plastic waste) used as fuel in the cement manufacturing process; second, to examine the impact of nitrogen oxides on the fine dust (<PM 2.5) generation characteristics in Gangwon-do Province, considering the conversion rate of nitrogen oxides into fine dust; and third, to evaluate the proportion of fine dust attributable to nitrogen oxides. Using these results, the study aims to assess how much the fine dust concentration can be reduced by tightening the nitrogen oxide emission limit for cement plants to the level of waste incineration plants, and to propose policy alternatives to the government and Gangwon-do Province.

 

Acknowledgments

"This research was supported by Particulate Matter Management Specialized Graduate Program through the Korea Environmental Industry & Technology Institute(KEITI) funded by the Ministry of Environment(MOE)"