The researchers studied how activated carbon can help reduce harmful nitrogen oxides (NOx) in the air using ammonia (NH3). They found that when the ratio of nitrogen dioxide (NO2) to NOx was 1.0, more NOx was converted at temperatures between 90-210°C. Ammonium nitrate (NH4NO3) formed on the activated carbon at lower temperatures, but disappeared at higher temperatures, leading to better NOx conversion. The reaction rate increased with temperature, reaching a maximum of 79.5% at 210°C. The study showed that NH4NO3 plays a crucial role in the process, forming from NH3 and NO2, and being consumed by NO and carbon. This research provides insights into how activated carbon can be used as a catalyst to remove NOx at low temperatures.