Inclusion Criteria:  Daily consumption of tobacco products (including traditional cigarettes, electronic cigarettes, and heated tobacco products) in the past week; Age ≥18 years; Owning a mobile smartphone with internet access; Staying in Hong Kong during the 1-week EMA study period; Able to read and write Chinese Exhaled carbon monoxide will be measured and required to be 4ppm or above  Exclusion Criteria:  Plan to use smoking cessation services or medication in the coming month Using smoking cessation services, or using nicotine replacement therapy in the past 7 days Having mental illnesses Female smokers who are pregnant