The study analyzed different chemical components in tobacco leaves from Qujin to understand their quality. The researchers found that most chemical levels met quality standards, except for some variations in sugar, nicotine, and potassium. The levels of most chemicals remained stable across different counties, years, and tobacco varieties. They also discovered strong correlations between certain chemicals, like sugar and nicotine. To improve the quality of Qujin tobacco, the researchers suggest controlling sugar levels, balancing sugar to nicotine ratios, and increasing potassium content.