BACKGROUND: Ambient air pollution could increase the risk of hypertension; however, evidence regarding the relationship between long-term exposure to particulate matter and elevated blood pressure in plateau areas with lower pollution levels is limited. METHODS: We assessed the associations of long-term exposure to particulate matter (PM, PM, PM, and PM) with hypertension, diastolic blood pressure (DBP), systolic blood pressure (SBP) and pulse pressure (PP) in 4.235 Tibet adults, based on the baseline of the China multi-ethnic cohort study (CMEC) in Lhasa city, Tibet from 2018-19. We used logistic regression and linear regression models to evaluate the associations of ambient PM with hypertension and blood pressure, respectively. RESULTS: Long-term exposure to PM, PM, and PM is positively associated with hypertension, DBP, and SBP, while negatively associated with PP. Among these air pollutants, PM had the strongest effect on hypertension, DBP, and SBP, while PM had the strongest effect on PP. The results showed for hypertension odds ratio (OR) = 1.99; 95% confidence interval (CI) = 1.58, 2.51 per interquartile range (IQR) μg/m increase in PM, OR = 1.93; 95% CI = 1.55, 2.40 per IQR μg/m increase in PM, and OR = 2.12; 95% CI = 1.67, 2.68 per IQR μg/m increase in PM. CONCLUSIONS: Long-term exposure to ambient air pollution was associated with an increased risk of hypertension, elevated SBP and DBP levels, and decreased PP levels. To reduce the risk of hypertension and PP reduction, attention should be paid to air quality interventions in plateau areas with low pollution levels.