Burning gas, wood, and biomass in buildings now has more negative health effects than burning coal in many states, says a new study from Harvard T.H. Chan School of Public Health. The peer-reviewed study, published in Environmental Research Letters, is the first to examine the effects of burning different fuels and quantify those impacts in terms of both early deaths and monetary cost in the United States.
Below, RMI’s Carbon-Free Buildings team answers seven key questions about the study, particularly as it relates to buildings.
What is the study about?
Over the past decade, coal pollution dropped dramatically, but the public health burden of outdoor air pollution from other sources has not been well understood. This study fills an important gap by providing an inventory of outdoor health impacts from stationary sources — power plants, buildings, industrial boilers, and other industries. It analyzes how the US energy transition from 2008 to 2017 has affected public health by examining the impacts of particulate matter (PM2.5) and its precursor emissions on early deaths and the resulting economic health cost.
The burning of fuels releases PM2.5, a mixture of solid particles and liquid droplets, some of which are visible — such as smoke, dust, or soot — and some of which are invisible. PM2.5 pollution is particularly dangerous due to its tiny size (2.5 microns or smaller), as the microscopic particles can penetrate deep into the lungs and even the bloodstream. PM2.5 exposure can lead to a variety of negative health impacts, including cardiovascular and respiratory disease, stroke, asthma, autism spectrum disorder, and premature mortality.
What are the key takeaways about buildings and their impact on health?
In just a decade, the leading estimated cause of death from stationary source outdoor air pollution changed dramatically. In 2008, coal plant emissions were the most harmful sources of PM2.5 air pollution, but by 2017, the sum of emissions from gas, biomass, and wood burned in industrial boilers and buildings surpassed the impact from coal plants. Study projections for 2018 show that trend likely continued.
Taken together, commercial and residential buildings are now responsible for approximately 18,300 early deaths and $205 billion in health impacts — one-third of the health burden from stationary sources in the United States. This statistic is conservative, as it only includes health impacts from one outdoor pollutant and does not account for emissions generated by fuel extraction or the potentially significant health impacts from indoor air pollution generated by burning fuels.
The message is clear: to improve health outcomes, we must stop burning fuels in buildings. Swapping one polluting fuel source for another is not a pathway to a healthy energy system. Combustible fuels such as gas, biomass, and wood lead to substantial health burdens that have grown over the past decade.
How can we put these figures into perspective?
Overall, the study’s findings are staggering. Early deaths attributed to air pollution from stationary sources are between 48,000 and 64,000 a year. If this type of air pollution was considered a “cause of death,” it would rank as the eighth leading cause of death in the United States, just below diabetes and similar to influenza and pneumonia.
These stationary sources were responsible for an estimated $615 billion in health impacts in 2017. This is substantial, considering that only six companies have ever been valued at over $600 billion (Tesla, Amazon, Apple, Facebook, Google/Alphabet, and Microsoft).
What new insights does this study provide that we didn’t have before?
Although other studies have presented similar analyses, this is the first to break down and quantify premature deaths and health burdens explicitly by different fuel sources (gas, coal, oil, biomass, wood) burned in coal plants, buildings, industrial boilers, and other industries.
The Harvard study is also the first to quantify the public health burden, in dollars, of burning fuels in US stationary sources. If the $615 billion attributed to 2017 health impacts from these sources were distributed across the US population, every American would get a check for nearly $2,000. Buildings were responsible for approximately one-third of the total cost (nearly $205 billion).
What trends appeared?
The big picture is that as the health impact of coal declined, the relative influence of gas and other dirty fuels has increased. In 2017, the health impacts of gas surpassed coal in at least 19 states plus D.C. in nearly every stationary sector except electricity generation.
The impacts from gas are particularly prominent in the building sector. In commercial buildings, gas is the leading fuel source contributing to early deaths and health costs. In residential buildings, health impacts are dominated by wood, followed by gas. It is important to note that although gas is the dominant fuel source in most US homes, wood leads in health impacts in most states because it emits much higher levels of primary PM2.5 compared to other fuels.
Two states — New York and Illinois — appear to be outliers, as gas leads health impacts from the residential sector, whereas the rest of the states are dominated by wood. As coal plants continue to close, these trends are likely to continue.
How did the researchers calculate the impacts?
To calculate these impacts, the authors used:
- National Emissions Inventory (NEI) data from the Environmental Protection Agency,
- the State Energy Data System (SEDS) from the US Energy Information Administration,
- and three reduced complexity models that estimate health-related social costs of air pollution emissions in the United States.
The 2008–2017 data was collected from the contiguous 48 states, the District of Columbia, and Indigenous American Land. In the absence of NEI data for 2018, the researchers made projections based on available state data.
The study focused on PM2.5, which includes primary PM2.5 and four precursor pollutants: nitrogen oxides (NOx), sulfur dioxide (SO2), volatile organic compounds (VOCs), and ammonia (NH3). Whereas primary PM2.5 is particulate matter released directly into the air, precursor pollutants are gases that react in the atmosphere to form secondary PM2.5. The researchers used estimates of how the risk of premature death increases with greater PM2.5 exposure to calculate the premature deaths for this study. To calculate the costs of the health burden, the researchers estimated the value of a statistical life at $11.2 million, which is a commonly used method in public health research and by the EPA to estimate the benefits of reducing human mortality risk. Essentially this means that every premature death caused by PM2.5 pollution is worth $11.2 million. Another way to think about this is that the value of reduced risk of dying from air pollution is worth $11.2 million per life.
More importantly, the reported health impacts of these pollutants are conservative estimates because they only account for emissions from stationary sources into the outside air and do not include the full-life cycle emissions. This means the study does not account for indoor exposure or the emissions from the extraction or production of any of the fuels. Additionally, due to the complexity of the models, the study only considered PM2.5, but there are other harmful pollutants that, if considered, would show an even more significant health burden. For instance, ozone and direct exposure to NO2 both cause health problems.
How can states act on this new information? And how does building electrification fit in?
As a first step, we need to draw attention to the health impact of burning fuels in buildings. While pollution from other sectors, like transportation and industry, are prioritized by policymakers and advocates, this study provides concrete data showing that building pollution has contributed substantially to negative health impacts and will likely continue to do so.
Policymakers can ensure that new construction is all-electric, saving money and safeguarding health at the same time. States should reevaluate regulations on wood and biomass appliances, while also committing to decarbonizing stationary sources as well as cars and other industry. This research is an important tool for policymakers considering how to regulate building emissions and increase building electrification in tandem with decarbonizing the grid. Using state data from the study, RMI has created an interactive map that breaks down the health impact in terms of early deaths and cost burden by state. This information is valuable for policymakers in conducting cost-benefit analysis and providing a fact base for action.
Our health and energy policies are inextricably linked. Many policies have supported switching from coal to gas, but the healthiest option is to leapfrog to clean electricity or other noncombusting energy sources to power our stationary sources and reduce air pollution. Policymakers can and should use this research to factor in the health impacts of energy policy decisions.
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