Particulate Matter, Blood Pressure, and the Sympathetic Nervous System
Condition: Air Pollution
Study type: Interventional

Summary: 
      Healthy volunteers will be exposed to ambient air near a roadway under the conditions of with
      and without a facemask and their responses will be evaluated.
    

Detailed description: 
      The investigators will enroll 50 healthy nonsmoking adults (20-65 years old) into a protocol
      involving 2 separate 5 day long "study blocks". Each block will consist of 5 separate 2
      hour-long "exposure periods" conducted 5 days in a row (Monday - Friday; start: 8 am to end:
      10 am) (Table 2: Study flow chart). Investigators will enroll 2 patients to undergo the trial
      study blocks simultaneously (one subject starting block 1 in the active intervention by
      wearing the facemask and the other wearing no facemask to begin block 1). Day 1 (Monday) of
      each study block will occur in a non-polluted clean indoor setting (Research Exam Room, Suite
      A 1310; Lobby A, Dominos Farms). All subsequent exposure periods (days 2-5, Tuesday through
      Friday) of each study block will all take place at the same designated "exposure site", an
      Ann Arbor Transportation Association (AATA) parking lot area nearby several busy roadways in
      Ann Arbor MI. To complete the entire study, each subject will perform 2 separate study
      blocks. Minimal total study duration is 2 weeks (washout period = 2 days over weekend) to a
      maximal period of 6 weeks (wash out period = 5 weeks). During one block, subjects will wear
      an N-95 respirator facemask (active intervention) during all exposure periods (days 1-5, even
      during day 1 indoor exposures). Subjects will remove the mask at the end of the study day
      after all testing is completed. Active versus control intervention ordering will be performed
      in a randomized single-blind cross-over order. During the other block subjects will wear no
      facemask (control) during exposure periods. While subjects will necessarily be aware of the
      intervention type, the study investigators responsible for evaluating the results will be
      blinded to the intervention type during all data analyses (i.e., single blind trial).
      Throughout all exposure periods, subjects will wear ambulatory BP monitors (ABPM) and ECG
      Holter monitors to determine brachial BP/aortic hemodynamics measured every 10 minutes and
      heart rate variability (HRV) metrics measured continuously and averaged into 10 minute epochs
      corresponding to same time periods as the BP levels, respectively. Air pollution exposures
      (PM2.5, black carbon (BC), and ultrafine particle (UFP) count), ambient temperature levels,
      and noise intensity will be measured continuously at the near-roadway exposure site during
      all exposure periods (Days 2-5). All environmental exposure metrics will also be averaged
      into 10 minute epochs during the exposure periods corresponding to the health outcome times.
      Following completion of exposure periods on day 4 (Thursday), subjects will have endothelial
      function measured by endoPAT (RHI) immediately post-exposures at the near-roadway site, after
      lying supine resting 5 minutes on a portable support. Patients will wear facemask throughout
      RHI testing when in the active intervention block. On the final day 5 of each study block,
      all subjects will have blood drawn. A sub-group (n=20) of subjects (enrolled on a first-come
      basis) will have SNS activity measured by MSNA. After blood draws on each study visit day
      subjects will remove the facemasks and can thereafter carry on with their routine daily
      activities. However, subjects will be asked to not deviate from their usual lifestyle during
      each study block. Subjects will be specifically directed to not significantly change their
      lifestyle (e.g., diet, sleep patterns) and/or any routine activity (e.g., exercise regimen,
      work, commutes, travel) throughout each study block.
    

Intervention name(s): exposure to particulate matter with N 95 facemask; exposure to particulate matter with no face mask
Intervention type(s): Other; Other
Intervention description(s): 2 hours' / day exposure to particulate matter face mask worn during exposure.; 2 hours'/ day exposure to particulate matter with no face mask
Other intervention name(s): Dettol PROTECT+ Smart Mask
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: None (Open Label)
Primary purpose: Prevention