A comprehensive study by UNC-Chapel Hill and international collaborators found that aged biomass smoke, heavy with 4-nitrocatechol, poses a substantial threat to lung health. The team’s findings emphasize urgent public health concerns for areas prone to both wildfires and urban pollution.
Burning biomass — whether from wildfires, household wood stoves or agricultural activities — emits vast quantities of tiny particles and harmful chemicals into our atmosphere. These airborne pollutants are not just detrimental to the environment; they also pose significant health risks, particularly to the respiratory system. A recent study published in Environmental Pollution sheds light on why aged smoke may be more hazardous than fresh emissions.
The study, co-authored by Jason Surratt, a professor of chemistry at the University of North Carolina at Chapel Hill, examined the effects of two crucial components of biomass smoke — levoglucosan and 4-nitrocatechol — on human lung cells. The research brings to the forefront the heightened dangers of aged biomass smoke, which undergoes chemical transformations in the atmosphere.
“Biomass smoke, especially aged smoke containing 4-nitrocatechol, can have serious health consequences,” Surratt said in a news release.
Biomass burning refers to the process of burning organic materials like wood, leaves and crop residues, releasing carbon-based aerosols that greatly contribute to air pollution. Among the myriad chemicals produced, levoglucosan and 4-nitrocatechol are noteworthy.
Levoglucosan, a sugar-like compound, is released during the burning of wood. In contrast, 4-nitrocatechol forms when smoke interacts with nitrogen oxides common in urban settings, a process termed chemical aging.
The study aimed to reveal the toxicological effects of these compounds on lung health. The team, encompassing experts from the UNC Gillings School of Global Public Health, the Polish Academy of Sciences and the Príncipe Felipe Research Center Foundation (CIPF), carried out lab experiments on two types of lung cells: normal lung-lining cells (BEAS-2B) and lung cancer cells (A549).
Exposing these cells to various concentrations of levoglucosan and 4-nitrocatechol over 24 and 48 hours, the researchers measured cell survival, stress levels and mitochondrial damage. The study found that 4-nitrocatechol was significantly more cytotoxic than levoglucosan.
Their striking results showed that even at low doses, 4-nitrocatechol drastically reduced cell survival and induced oxidative stress, an imbalance that can pave the way for lung diseases. It also impaired mitochondrial function, leading to apoptosis — programmed cell death — which could potentially contribute to long-term lung complications.
While levoglucosan also caused cellular stress, its effects were less severe. Cells exposed to levoglucosan displayed signs of mitochondrial distress but were capable of recovering over time.
Given that 4-nitrocatechol forms when biomass smoke reacts with urban air pollutants, areas experiencing both wildfire smoke and traffic pollution face heightened risks. This revelation calls for urgent action and improved public health strategies in vulnerable regions.
To mitigate the health risks of biomass smoke, individuals can adopt several protective measures:
- Use HEPA air purifiers to remove fine particles and keep windows and doors closed to minimize smoke infiltration.
- Ensure homes are well-sealed to prevent smoke entry through cracks, vents or poorly fitted windows and doors.
- Avoid indoor sources of pollution, such as candles, gas stoves or burning wood.
- In severe conditions, consider using gas masks with activated carbon filters to remove particles and harmful gases.
- If air quality remains hazardous, relocating to areas with cleaner air may be the safest option.
“Our study reinforces concerns that exposure to biomass smoke — especially aged smoke containing 4-nitrocatechol — can have serious health consequences,” Surratt added. “Long-term exposure to these pollutants has been linked to respiratory diseases such as asthma, chronic obstructive pulmonary disease and lung cancer. People who live in wildfire-prone areas or who frequently burn wood for heating should take extra precautions.”
The findings emphasize the urgent need for robust public health policies and improved air quality management, particularly in regions susceptible to wildfires and heavy traffic pollution.