A news study out from researchers at Harvard University this week looked at an under explored component of energy transition, air pollution. For years, when researchers, activists, or politicians talked about moving from coal to natural gas, they focused on greenhouse gas emissions and specifically carbon dioxide emissions, which are
lower for gas than coal. Over the past five years or so, we've gotten plenty of studies around that other greenhouse gas, methane, and how the transition to gas has generated a massive amount of it, But we haven't heard much about air pollution, so researchers at Harvard's School of Public Health turn their attention there. The good news is that overall energy use is less of a contributor to air pollution than it was when everything was coal fired.
The bad news is that it's still a primary contributor, and that gas and biomass are the key culprits. In other words, once again, we're finding out that these bridges to clean energy have only really served to impede progress and perpetuate the same old problems. Two of the studies authors, Jonathan Bonacore and Parishar Salimifhard, joined me to discuss their findings. That conversation coming up after this quick break you're listening
to drill. I'm Amy Westervelt. I'm really interested in this paper, and I wanted to kind of start with maybe having you both introduce yourselves and then tell me a little bit about what prompted you to look into this in the first place.
So let's start. I guess I'm Jonathan Buincorr. I'm a research scientist at the Center for Climate Health and the Global Environment at the Harvard tch chance School of Public Health.
Hi, my name is Patty Chasteli Mifad. I'm a post doctor LFLO and how books.
Okay, great, I guess I guess to start with the how we kind of got started down this line of inquiry was that, I mean, as you're probably aware, there's been all kinds of research about the climate effects of natural gas and the transition away from coal to gas.
There's been all this research about how the conversion in the electricity sector from cole to gas has affected greenhouse gas missions of the United States, and some discussion on the life cycle greenhouse gas impacts with like methane links and those kinds of things. And this research is all great there's a lot of good stuff out there, but one of the things that it doesn't do is it does not address questions about what the changes to health
impacts due to the energy choices were. So that's part of the emphasis of this paper is just to kind of get started answering that particular question is what is you know, we know a fair amount about the greenhouse gas implications of this transition from coal to gas, and this is starting to fill in that question regards to public.
Health, right right. You know, I have to say that I was surprised at how much biomass impact there is, just because I feel like, I don't know, it just doesn't get talked about as much as something that was widely embraced. It almost seemed like from the climate side, it seemed like people talked about it a lot and then kind of decided, oh, actually this isn't a great solution, and then stop talking about it. But it seems like from your research that quite a few buildings tansition to
biomass and it's having a big impact. So I'm curious about what you found on that front. And then I want to get into the natural gas stuff after that.
Yeah, so the finding about biomass was kind of a surprise to us too. We kind of figured, like, you know, while we're looking at coal and gas, we might as well look at all the other energy resources that have been used in you know, buildings, electricity, and industrial boilers. And yeah, that was a big surprise to us too, is that the impact of wood and residential buildings, wooden biomass and commercial buildings and the wooden biomass use in
industrial boilers were all growing. And for the boilers and industrial boilers and for residential buildings, those were really high impacts and kind of made it to kind of the top shelf of impactful sources that we found.
Just adding to John has point and also to what you mentioned your question, actually that because that is true that because in our climate policy and climate action plans we have been many focused on being huse gas emissions some of these and I just also have been kind of going under the radar of how we have looked at them and their emissions. And the biomass can be an example because we also regard them usually as renewables.
But they didn't talk about or did not have a good understanding of how much of health impacts they have, and that can be a good example of why health and energy should be looked at together and we shouldn't look at climate actions just by focusing on doing husse gas emissions.
Yeah. Yeah, did you get a sense in your research of just, you know, kind of what percentage of buildings are actually using biomass now as opposed to other I just like I when I was reading your paper, I was like, God, I hadn't realized that it had been that widely adopted that it would now be like a dominant source of air push.
So right, Yeah, So the data that we used was based on it was a missions data that's collected by the EPA, So we don't have information on like the number of buildings that are using these different field sources.
But I think one of the things that contributed to that is rather than not just like the sheer number of buildings that are converted, it's more of the fact that these sources looks like they can be fairly high emitting a few a few sources that could be small will admit a fair amount, right, And that's more what's driving the impact parsure. You had something you looked into the emissions factors for some of that right, Yes, that is so.
Adding to what Jonathan said, we don't have the percentage of how many number of buildings are using what fuel type, but we do have amount of energy consumption in residential building sector. Just looking at the quantity the amount of energy that is being used in residential buildings, for example, natural gas has much higher amount of energy use compared to biomass. However, we see health impacts of biomass is dominating the residential sector and is because of what Jonathan
mentioned is the emission factor. So for one unit of energy that biomass is providing, we have higher emissions usually, however, I should not hear that there is a variation in emission factors. So we have different types of biomass, and would some of them have lower emission factors some of them have higher. For example, wood is one of the highest air putent emit emitting fuels in the biomass category.
But looking at the health impacts specifically, one thing that we did find in our results was that looking at the different states in residential sector, combustion of wood and combustion of wood was dominating the health impacts in almost every state except for just two which was New York State and Illinois.
Wow. Wow, that's really interesting. I'm curious to hear more about the natural gas impacts too. So there was one line in your paper that I was like, wow, that's interesting, and that was let's see it says all three RCMs indicate that gas had higher health impacts than coal in eight states in two thousand and eight, and that number increased to twenty in twenty seventeen. Could you talk a
little bit about that? And I think there is this kind of persistent idea that because of what you were talking about before, that we focus on greenhouse gas emissions and climate and not you know, the more sort of immediate health impacts that I do think that people have kind of glossed over the fact that natural gas does actually create immediate pollution too. So yeah, I'm curious to have you just lay out, you know, what that result
kind of means. And I know you do that in your paper, but just to have it on audio too.
Yeah, Well, I think, I mean, I think pretty simply what it means is that like basically, if you swap out one combusting fuel for another combusting fuel that is not a catholic, that's going to get you to a healthy energy system. I mean, when you combust anything, it will produce air pollution, and you know if you inhale that it is going to be harmful no matter where it comes from.
Do you think you know there should be more studies of this this type that look at you know, kind of beyond greenhouse gas emissions around energy sources. But also do you think that like this kind of feeds into the need to to just sort of rethink how how we evaluate and embrace you know, quote unquote climate solutions in the first place, that this this kind of idea of just sort of swapping out one energy source for another is maybe a bit simplistic.
Yeah, I definitely agree on that point that it's simplistic. I mean with in greenhouse gas world and just climate world. I mean, energy choices gets a lot of the intention, I feel like, and I think there's there's not as much attention paid as there should be to the fairly large impact that air pollution has on public health. I mean we've been seeing kind of study after study about this.
I mean recently there was the study showing that there's like around eight million deaths worldwide due to air pollution from fossil fuels. So it's a big deal for public health, and I think yeah, so, I think I think it's it's not evaluated as much as it really should be. And what we're seeing is that these kinds of health decisions are Sorry, the kind of health aspects of energy is.
It's becoming more and more a really big factor in terms of decision making about what type of energy and climate policies we have, and I think that's only going to continue in the future as we're continuing to rightfully put more and more focus on both public health and sort of the equity implications where you know, again with a lot of these fuel combusting sources, they're often around you know, black, indigenous or communities of color, So making
the correct choices around what those folks are getting exposed to is really important for not just public health, but for equity and in frontal justice as well.
Yeah.
Yeah, Can you talk a little bit about the specific health related emissions associated with natural gas kind of what they are and their impacts.
Yeah, so we do see it's a pretty steep decline in health impacts due to coal combustion and a lot of with coal, a lot of the impacts there are coming from primary PM two point five emissions. So these are things that are admitted sort of, this is what everybody gets exposed to in the end, and this is like just primary exposure of just particles that are suspended in the air. The other thing, other main pollutant leading to the coal health impacts is SO two sulfur dioxide.
It forms sulfuric g acid and forms sulfate particles, which is a type of PM two point five, which then people inhale and results in all the health effects that we know about for PM two point five. So in terms of the air pollution from natural gas gas, that's a little bit of a different profile. There is some emissions of that primary PM two point five, but with gas there's a bigger proportion of it is coming from
NOTO a NOx NOx similar to SO two. It can when it's emitted, it eventually reacts with other pollutants downwind and forms PM two point five, which we then get exposed to and causes the harmful health effects we know about.
The other one, strangely is ammonia. This was another kind of almost atmospheric chemistry surprise, where there's a fairly high ammonia emissions from natural gas, especially when it's burnt in residential buildings, which leads to fairly high impacts areas around those buildings.
That's super interesting too, So what do you plan to look at next? I know, I saw something in here about you know that kind of looking at current projections, it seems like these trends continue in twenty eighteen. So I imagine that you're planning to continue looking at this as data is available. But are there other kind of areas that you want to look into?
Yeah? I think, as I was talking about with this kind of the comparison to the greenhouse gas footprint, you have to look across again the full life cycle, including both combustion, pipeline, storage, processing, and activity in the well.
So that's largely been done for greenhouse gas emissions, hasn't been done for health, and we would like to do that to look at the full life cycle health impacts of gas from wellhead to point of combustion, whether that's a power plan in a building or a innustrial boiler. The other thing we'd like to do on top of that is to rerun this using a different, different set
of modeling platforms. Lets us catch health impacts of exposures to more different pollutants and do it in more geographic details. We'll be able to get county level health estimates and get estimates of the health of other health impacts related their pollution exposure like asthma, respiratory countiovascular hospitalizations, and other health impacts related their pollution exposure. Okay, py, sure you want to talk about the other stuff going on.
You have also some other studies that we are looking at to one of the previous points that we talked about having a more holistic assessment of climate policy plans that doesn't look at just climate impacts and going house gas emissions, but also health impacts of different client policies that are being proposed, specifically in building sector. So that is one of our other studies that we have been
working on. One example of that has been looking at the health and climate impacts of Local Law ninety seven in New York City that aims to that has actually mandated emission reduction from energy use in building sector from buildings that are larger than twenty five thousand square feet with the goal of reducing their gin house gas emissions forty person by twenty thirty and eighty percent by twenty fifty.
But that policy also being another example of focusing on even the goals are explicitly just talking about HAS gas emission reduction, we are looking at how that can impact health impacts.
Got it, That's interesting. Thank you guys both so much for speaking with me. That's it for this time. Big thanks to Jonathan and PARISHARV for joining me. I'll stick a link to their study in the show notes for those of you who want to dig in further. Also
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