Impacts of PM 2.5 on Ambulatory Blood Pressure Monitoring Indicators Attenuated by Blood Pressure Control Status and Treatment — Two Cities and Two Municipalities, China, 2017−2019

What is already known about this topic? Short-term PM2.5 exposure has been associated with hourly, 24-hour, daytime, and nighttime blood pressure (BP) levels, and further studies focusing whether and how the associations with other ambulatory BP monitoring indicators are warranted. What is added by this report? This study observed that short-term PM2.5 exposure was associated with BP elevations and was the first to report the associations of short-term PM2.5 exposure with BP variability. Circadian rhythm of BP and BP load among hypertensive patients were found to be modified by controlled BP status or taking angiotensin receptor blockers (ARBs). What are the implications for public health practice? This study suggested that antihypertensive therapy, especially with well-controlled BP status may be potential measurements to attenuate adverse impacts of PM2.5 for hypertensive patients with intermediate-to-high risk of cardiovascular disease (CVD).