In recent years, more and more young people from Hong Kong, Macao and Taiwan have come to universities in Chinese Mainland for higher education. However, due to the differences in political, economic and cultural environment between Hong Kong, Macao and Taiwan regions and Chinese
Mainland, these young people have encountered psychological problems such as examination anxiety, interpersonal loneliness and lack of sense of meaning in life due to the related learning and life difficulties in Chinese mainland universities, which affect their growth and success. Many of
the students originally thought that smoking was used in a more secluded environment to relieve stress, psychological counseling and energy recovery, but in fact smoking brings more harm. In the creation of a smoke-free campus, a variety of measures are adopted to give full play to the positive
emotions of students to promote their mental health, which will help to achieve the creation of a smoke-free campus and share a healthy life on the campus. Based on the survey of a total of 658 undergraduates from Hong Kong, Macao and Taiwan in H University on their positive affect and mental
health, the following conclusions are drawn through data analysis: undergraduates from Hong Kong, Macao and Taiwan in Chinese Mainland have positive affect at the upper-middle level, negative affect and overall affect at the lower-middle level; some undergraduates from Hong Kong, Macao and
Taiwan in Chinese mainland universities have middle-level mental health status and significant differences in grade and family relationship satisfaction; family relationship satisfaction has an important impact on students' emotional and mental health; the negative emotional performance and
mental health of senior students, science students and students with low family relationship satisfaction need more attention from educators. Correlation analysis shows that positive affect is positively correlated with health concerns, energy status, satisfaction and interest in life, mood
status, control of emotions and behaviors, relaxation and tension, and total score of mental health (P < 0.01). Regression analysis shows that positive affect has significant positive predictive effects on six factors in mental health, such as "health concerns", "satisfaction
and interest in life", "energy", "mental state", "control of emotions and behaviors", "relaxation and tension" and mental health. The enlightenment of this study lies in the suggestions that actions should be taken from the two levels of school
education and home-school combination to strengthen the cultivation of positive affect of Hong Kong, Macao and Taiwan undergraduates in Chinese mainland universities, so as to improve their mental health level.
Long-term O<sub>3</sub>–precursor relationships in Hong Kong: field observation and model simulation
