California Air Resources Board

Principal Investigator/Author: Allen Goldstein

Contractor: University of California, Berkeley

Sub-contractor: Kelley Barsanti (University of California, Riverside)

Contract Number: 19RD008

Project Status: Completed Dec 2023

Relevant CARB programs:AB 32 Climate Change Scoping Plan

Topic areas: Air Quality, State Implementation Plans (SIPs), Wildfire Emission Estimates

Research Summary:

California’s wildfires are getting worse with increased fire risks, higher frequency of occurrence, larger burn areas, and a longer fire season. Tracking with rising temperatures, California’s 2020 fire season has also been record-breaking, not only in the total amount of acres burned but also in wildfire size that destroyed over 10,000 structures and cost over $12 billion in damages. Prescribed/controlled burning is one wildfire mitigation strategy that can significantly reduce the spread and intensity of large wildland fires while improving forest resiliency, reduce overall GHG emissions, reduce the chance of extreme air quality degradation, and reduce human exposure to smoke. This research project will incorporate the use of novel measurement techniques such as all-terrain vehicles —equipped with comprehensive particulate matter (PM) and gaseous sampling platform—to surround all burn areas coupled with airborne (drone)-based measurements that were used to sample near-fire emissions during controlled burns at the Blodgett Research Station.

The objectives of this research project are:

• Improve prescribed burning and wildfire Emission Factors (EF) of gaseous and particulate pollutants from controlled burns and compare with those from wildfires, in order to understand how reducing fire risk through prescribed burns also alters emissions;
• Analyze data from black carbon network during wildfire smoke episodes reaching populated regions of California in 2018 and 2020; and
• Quantify indoor PM2.5 intrusions from outdoors using PurpleAir Network sensors during wildfire smoke episodes reaching populated regions of California in 2018 and 2020.

Data from this research project will provide us with the information needed to improve statewide wildfire emission estimates, understand and help mitigate future wildfire risks, and helps us understand the role of wildfires on ambient PM2.5 and the formation of secondary air pollutants. This project will also provide critical inputs for air quality modeling, and guidance for management efforts to reduce wildfires that are consistent with optimizing forest carbon storage, protecting public health, and promoting environmental justice.

Keywords: Emission Factors (EFs); prescribed/controlled burn; Blodgett Research Station; wildfire; First Order Fire Effects Model (FOFEM); volatile, intermediate, and semi-volatile organic compounds (I/S/VOCs); drone; all-terrain vehicles; community impacted by biomass burning plumes; understanding the dominant source materials burned; fire characteristics; atmospheric transformations; health implications

Final Report: Please email research@arb.ca.gov to request the Final Report generated by this research contract.