Wildland-Urban Interface (WUI) Smoke Production and Exposure Mitigation

Summary

Wildland-Urban Interface (WUI) fires generate significant smoke, but little is known about the smoke production rates and compounds found in the smoke when communities burn and the potential harm they may cause.  The exposure to smoke from these fires poses risks to first responders, evacuees, and residents of nearby communities. Moreover, buildings can be exposed to smoke during WUI fires affecting human health and building habitability after the fires are out. This project seeks to quantify the smoke production and chemical composition of WUI smokes and inform protective actions and mitigation activities.  

Description

Flaming combustion of a mixed fuel crib of wood, gypsum wallboard and plastics to simulate the fuel components of a residential structure. 

Credit: NIST

Objective
Develop measurement science and technology that enables 1) accurate estimates of WUI smoke production and its chemical makeup, and 2) assessment of hazards and effective mitigation actions to limit the smoke exposure to first responders, building occupants and WUI fire evacuees.  

What is the Problem?
Emissions from WUI fires can have significant negative impacts on human health, not only for those in the immediate vicinity—such as firefighters and residents—but also for individuals hundreds to thousands of kilometers downwind, especially in the case of large fires. Despite the scale of these risks, little is known about the specific emissions from WUI fires, including the amount of smoke produced by buildings, vehicles, and other infrastructure, as well as the chemical composition of that smoke. The presence of WUI smoke poses a serious threat to the health of occupants, evacuees, and first responders, both during the fire and afterward. Even after the flames are extinguished, smoke and ash can remain trapped inside buildings that survive the fire, prolonging exposure and exacerbating health risks.

Research Plan
The Fire Research Division has unique capabilities and expertise to gather WUI smoke emissions data including smoke yields, particle size and chemical constituents from small-scale experiments to full-scale experiments in the National Fire Research Laboratory at NIST where smoke from items as large as vehicles, large trees, and even small homes can be quantified. The Fire Research Division also partners with the Indoor Air Quality group in NIST’s Building Energy & Environment Division to address indoor air quality impacts and investigate mitigation from WUI smoke exposures to provide guidance to communities and input to codes and standards. The research plan is to develop the measurement capability to accurately gather representative samples of smoke from burning objects and deploy new sampling protocols and analytical methodologies for smoke chemical components in gaseous and solid particulate phases. Of particular interest are the yields of combustion gases, volatile organic compounds (VOCs) , semi-volatile organic compounds (SVOCs) , and elemental analysis including metals and halogen compounds using analytical equipment including Fourier transform infrared spectroscopy (FTIR), gas chromatograph-mass spectrometry (GC/MS), inductively-coupled plasma mass spectrometry (ICP-MS), combustion ion chromatography (CIC).

Smoke samples from objects found in the wildland urban interface and burned in the various calorimetry hoods are being gathered and analyzed to more fully characterize the smoke yields and chemical constituents. Efforts are underway to develop a WUI smoke source surrogate from small scale objects that will produce smoke with similar characteristics to full-scale items like homes. A standardized and well-characterized WUI smoke surrogate is essential for indoor air quality research within NIST and beyond. This is crucial for a wide range of studies, including smoke deposition and off-gassing experiments to evaluate non-thermal smoke damage and mitigation strategies. Additionally, it is needed for research on smoke aging, secondary aerosol formation, the evaluation of filtration systems for both particulate and gaseous pollutants, and studies on firefighter gear exposure to smoke and cleaning effectiveness..

Research is being conduction to assess the fate of WUI smoke that enters buildings from initial exposure to high levels of smoke to days after, and the effects of active filtration after exposure using advanced instrumentation to gather real time data. Efforts to bring relevant scientific knowledge to address WUI and wildfire smoke exposures to buildings to keep indoor air quality within safe levels being pursued through engagement with relevant codes and standards and best practices guidelines.