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Completed

NCT Number: NCT02769208

Influence of Indoor Air Filtration Strategies on Occupant Health Indicators

The purpose of this study is to evaluate whether two different central air purification technologies reduce air pollutant exposure and beneficially influence health as evaluated with a suite of biological markers related to cardiovascular and respiratory disease risk.

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Key information

Conditions

Risk Factors for Respiratory and Cardiovascular Disease Cardiovascular Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Shanghai First People's Hospital

Shanghai, Shanghai Municipality, 201620, China

About this study

This study will test two common types of central air handling unit filtration technologies, high-efficiency particulate air (HEPA) filters and electrostatic precipitators (ESPs), to evaluate the impacts of these technologies on personal exposure to air pollutants and the associated cardiovascular and respiratory health outcomes. HEPA filters remove a high percentage of the particulate matter in the air, as do ESPs, but ESPs also generate ozone, which may have its own detrimental health effects. These air purification technologies will be placed in different combinations with a coarse pre-filter to protect the air exchange machinery (combinations: pre-filter only, pre-filter + HEPA, and pre-filter + HEPA + ESP) in both the residences and offices of study participants living on a factory campus in Changsha, Hunan Province, China. Large dormitories and office buildings with central air handling units are common in China and around the world, and so adding air purification into the central ducts represents a practical strategy to reducing personal exposure to air pollution and related health outcomes. The Changsha area commonly suffers from high air pollution, and the dormitories and offices on this workspace are already outfitted with both HEPA filters and ESPs. Therefore, testing these technologies in this environment presents a natural experimental condition to test the benefits of air purification. The study investigators hypothesize that both the pre-filter + HEPA and pre-filter + HEPA + ESP conditions will reduce particulate matter exposure and reduce biological markers of cardiovascular and respiratory disease compared to the pre-filter alone, but that the ESP will generate enough ozone to lead to lower health benefits than HEPA+pre-filter condition.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Healthy adults;
  • Live and work at the Broad Town work campus in eastern Changsha, Hunan Province, China

Exclusion criteria

  • Has any of the following diseases: chronic respiratory, cardiovascular, liver, renal, hematological disease; diabetes mellitus;
  • Has any other diseases that may confound or complicate the effects of the intervention
  • Pregnant females

Treatment and study plan

Central air handling unit air purification technologies

Device

As described in the arm descriptions, the interventions involve changing the baseline pre-filter + HEPA + ESP conditions by removing either just the ESP or both the ESP and the HEPA for a five week period.

Other names: Pre-filter, HEPA filter, Electrostatic precipitator (ESP)

Primary outcomes

  1. Change from baseline FEV1

    Time frame: At baseline, 2 weeks and 4 weeks into the intervention period, and then 2 weeks post-intervention

    FEV1 (forced expiratory volume in the first second of exhalation, unit: liter) was measured by spirometry in all subjects at four separate time points to compare FEV1 changes at different times before, during, and after the filtration intervention as a marker of lung function.

  2. Change from baseline soluble P-selectin

    Time frame: At baseline, 2 weeks and 4 weeks into the intervention period, and then 2 weeks post-intervention

    Soluble P-selectin (a protein shed by activated platelets in the blood, unit: ng/ml) was measured by ELISA in plasma in all subjects at four separate time points to compare levels at different times before, during, and after the filtration intervention as a marker of platelet activation.

  3. Change from baseline von Willebrand factor (VWF)

    Time frame: At baseline, 2 weeks and 4 weeks into the intervention period, and then 2 weeks post-intervention

    VWF (a glycoprotein released by damaged vascular cells into the blood, unit: ug/ml) was measured by ELISA in plasma in all subjects at four separate time points to compare levels at different times before, during, and after the filtration intervention as a marker of endothelial cell damage.

  4. Change from baseline augmentation index (AI)

    Time frame: At baseline, 2 weeks and 4 weeks into the intervention period, and then 2 weeks post-intervention

    AI (a measure of how much the reflecting pulse wave augments the outgoing systole pulse wave, unit: N/A (index)) was measured by pulse wave analysis in all subjects at four separate time points to compare levels at different times before, during, and after the filtration intervention as a marker of arterial stiffness.

  5. Change from baseline systolic blood pressure (SBP)

    Time frame: At baseline, 2 weeks and 4 weeks into the intervention period, and then 2 weeks post-intervention

    Brachial SBP (unit: mm Hg) was measured by an oscillometric method in all subjects at four separate time points to compare levels at different times before, during, and after the filtration intervention as a marker of vasoconstriction.

  6. Change from baseline fractional exhaled nitric oxide (FeNO)

    Time frame: At baseline, 2 weeks and 4 weeks into the intervention period, and then 2 weeks post-intervention

    FeNO (produced from inflammatory nitric oxide signalling in the lung, unit: ppb) was measured with an ambient NO-scrubbing collection method and chemiluminescence in all subjects at four separate time points to compare levels at different times before, during, and after the filtration intervention as a marker of airway inflammation.

Secondary outcomes

  1. Change from baseline C-reactive protein (CRP)

    Time frame: At baseline, 2 weeks and 4 weeks into the intervention period, and then 2 weeks post-intervention

    CRP (an inflammatory protein in the blood, unit: ng/ml) was measured with an ELISA in blood samples for all subjects at four separate time points to compare levels at different times before, during, and after the filtration intervention as a marker of systemic inflammation.

  2. Change from baseline 8-hydroxy-2'-deoxyguanosine (8-OHdG)

    Time frame: At baseline, 2 weeks and 4 weeks into the intervention period, and then 2 weeks post-intervention

    8-OHdG (a product of DNA oxidation found in the urine, unit: ng/ml) was measured with LC-MS in urine samples for all subjects at four separate time points to compare levels at different times before, during, and after the filtration intervention as a marker of systemic oxidative stress.

  3. Change from baseline exhaled breath condensate malondialdehyde (EBC MDA)

    Time frame: At baseline, 2 weeks and 4 weeks into the intervention period, and then 2 weeks post-intervention

    EBC MDA (a product of lipid oxidation found in the exhaled breath, unit: nM) was measured with HPLC in exhaled breath condensate samples for all subjects at four separate time points to compare levels at different times before, during, and after the filtration intervention as a marker of airway oxidative stress.

  4. Change from baseline exhaled breath condensate nitrite + nitrate (EBCNN)

    Time frame: At baseline, 2 weeks and 4 weeks into the intervention period, and then 2 weeks post-intervention

    EBCNN (a product of airway inflammatory NO signaling found in the exhaled breath, unit: uM) was measured with HPLC in exhaled breath condensate samples for all subjects at four separate time points to compare levels at different times before, during, and after the filtration intervention as a marker of airway inflammation.

  5. Change from baseline exhaled breath condensate pH (EBC pH)

    Time frame: At baseline, 2 weeks and 4 weeks into the intervention period, and then 2 weeks post-intervention

    EBC pH (a characteristic of exhaled breath associated with inflammation, unit: pH) was measured with a pH meter in exhaled breath condensate samples for all subjects at four separate time points to compare levels at different times before, during, and after the filtration intervention as a marker of airway inflammation.

  6. Change from baseline diastolic blood pressure (DBP)

    Time frame: At baseline, 2 weeks and 4 weeks into the intervention period, and then 2 weeks post-intervention

    DBP (unit: mm Hg) was measured with an oscillometric method for all subjects at four separate time points to compare levels at different times before, during, and after the filtration intervention as a marker of vasoconstriction.

  7. Change from baseline forced vital capacity (FVC)

    Time frame: At baseline, 2 weeks and 4 weeks into the intervention period, and then 2 weeks post-intervention

    FVC (unit: liter) was measured with spirometry for all subjects at four separate time points to compare levels at different times before, during, and after the filtration intervention as a marker of airway function.

Sponsors and collaborators

Lead sponsor

Feng Li

Other

Collaborators

  • Duke University
  • Rutgers University
  • Tsinghua University

Registry information

Important dates

Study start
2014
Primary completion
2015
Study completion
2015
First posted
May 11, 2016
Registry last updated
Jun 1, 2016

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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