UC Berkeley

Worldwide, nearly 3 billion people—40% of the global population—burn wood, coal, and other solid fuels every day to cook their food; this number is even larger when including those who heat their homes with solid fuels as well. Exposure to pollution from heating and cooking fires causes about 3 million deaths each year, making it one of the biggest environmental health problems the world faces. The harm from this smoke is not restricted to those who breathe it, however: it contains gases and particles that contribute to global climate change as well.

Chapter 2 shows that household cooking with solid fuels caused an estimated 12% of population-weighted ambient PM2.5 worldwide in 2010. Exposure to this air pollution caused the loss of 370,000 lives and 9.9 million disability-adjusted life years (DALYs) globally in the same year.

In Chapter 3 I demonstrate that household heating with solid fuels caused an estimated 21% of population-weighted ambient PM2.5 in 2010 in Central Europe, 13% in Eastern Europe, 12% in Western Europe, and 8% in North America. Exposure to this air pollution results caused approximately 60,000 premature deaths in Europe, and nearly 10,000 deaths in North America, as well as an estimated 1.0 million disability-adjusted life years (DALYs) in Europe and 160,000 DALYs in North America.

Chapter 4 addresses drivers of household wood combustion pollution in the San Francisco Bay Area, where the sector is the largest source of PM2.5 and regulators recently introduced amendments to wood burning rules for the airshed. Fireplaces are the source of the vast majority (84%) of PM2.5 from residential wood combustion in the San Francisco Bay Area, despite their use primarily as an aesthetic or recreational combustion activity. By evaluating hypothetical fuel and combustion device changeouts, I find that replacing fireplaces with gas would yield significant health and economic benefits. Specifically, retrofitting frequently used fireplaces (300,000 units) to gas inserts in the Bay Area’s nine counties would reduce sector emissions by about 90%, avoiding approximately 140-310 premature deaths and 19,000 lost days of work each year, and creating upwards of $1 billion in annual financial benefits from improved public health.

Chapter 5 explains methodological overlaps and differences between the previous chapters. In Chapter 6, I explore the current regulatory and policy mechanisms specific to household heating with solid fuels, and relate these to the climate change implications associated with the sector. In Chapter 7, I highlight the relative dearth of data on household heating with biomass and its nuanced climate implications. This leads to a series of recommendations for future research, including collection of better household heating data in China and further work to understand how household combustion of biomass interfaces with both local air quality policy and climate change mitigation, outlining areas where this topic is currently visible in California.