Sub-Clinical Effects of Outdoor Smoke in Affected Communities

Area of Science:

• Environmental Health
• Respiratory Medicine
• Toxicology

Background:

• Australians frequently experience landscape fire smoke from wildfires and planned burns.
• Older populations may be particularly vulnerable to the health impacts of smoke exposure.

Purpose of the Study:

• To investigate the effects of outdoor smoke from planned burns, wildfires, and a coal mine fire on inflammation biomarkers.
• To assess the relationship between fine particulate matter (PM2.5) concentrations and health measures in an exposed population.

Main Methods:

• Continuous measurement of PM2.5 concentrations in three southeastern Australian communities.
• Recruitment of predominantly older participants to perform health measures during and without smoke events.
• Analysis of changes in biomarkers, including fractional exhaled nitric oxide (FeNO), total white cell, and neutrophil counts, in response to PM2.5 levels.

Main Results:

• Increased FeNO levels were associated with a 4-hour lag following a 10 µg/m³ increase in PM2.5 from outdoor smoke.
• Wildfire smoke showed effects on FeNO at 4, 12, 24, and 48-hour lags; coal mine fire smoke showed effects at a 4-hour lag.
• Total white cell and neutrophil counts declined in response to a 10 µg/m³ increase in PM2.5.
• No significant effects were observed on other blood biomarkers from exposure to landscape fire smoke.

Conclusions:

• Landscape fire smoke, including from wildfires, planned burns, and coal mine fires, can impact respiratory inflammation (FeNO) and blood cell counts in older adults.
• FeNO is a sensitive biomarker for short-term exposure to PM2.5 from various outdoor smoke sources.
• Further research is needed to understand the long-term health consequences and the impact on other biomarkers.