According to a new study I co-authored, individuals living near busy highways can experience short-term improvements in blood pressure by using air filters indoors. Areas surrounding major roadways have high levels of air pollution, including ultrafine particles from burning fuel that are microscopic, invisible, and odorless. Alongside my colleagues Neelakshi Hudda and Misha Eliasziw, we investigated the impact of using indoor air filters near highways to reduce exposure to ultrafine and other particulate pollutants and how this affects blood pressure. Our research involved 77 participants who attended three two-hour sessions in a room adjacent to a busy highway. We varied the pollution levels in the room using portable air filters, windows, and doors, creating low, medium, and high exposure scenarios to ultrafine and other particles. Blood pressure measurements were taken from the participants every 10 minutes.
Our findings indicated that blood pressure correlates with the level of exposure to ultrafine particles: higher pollution levels led to higher blood pressure. Importantly, we also discovered that air filters effectively reduce pollution and the related increase in blood pressure. Although the blood pressure differences between high and low exposures were relatively minor, less than 3 mm of mercury, such changes could affect the risk of heart attacks and strokes if maintained over longer periods than our two-hour sessions. Numerous studies have associated living near heavily trafficked roads with negative health outcomes. Researchers acknowledge that particulate air pollution can impact cardiovascular health, with much of the research focusing on larger particles, known as PM2.5. My colleagues and I are contributing to the Community Assessment of Freeway Exposure and Health, which targets much smaller ultrafine particles.
Presently, there are no regulations governing ultrafine particle emissions, and they have not been as extensively studied as PM2.5. Our work and other research have linked them to increased inflammation markers and elevated blood pressure. Motor vehicles will continue to emit pollutants for the foreseeable future. Since the source of these pollutants isn’t likely to disappear soon, improving indoor air quality for residents living near busy roads seems to be an effective strategy for enhancing their health. Our study indicates that air filters can significantly lower blood pressure. Although this work is promising, its controlled setting might not translate to everyday life benefits. For those who are often home with closed windows, it seems likely that air filters would provide a similar reduction in blood pressure as seen in our study. However, many individuals leave their homes for work or school for extended periods. Whether there will be sufficient blood pressure reduction to yield health benefits in these instances is uncertain. My colleagues and I are currently enrolling participants for a new study to investigate whether such benefits can be achieved by placing air filters in people’s homes in real-life situations.