Air Pollution Kills Thousands of Americans Yearly – Here’s a Low-Cost Strategy to Help
By Jason West and Yang Ou
About one of every 25 deaths in the U.S. occurs prematurely because of exposure to air pollution. Dirty air kills roughly 110,000 Americans yearly, which is more than all transportation accidents and shootings combined.
When the U.S. Environmental Protection Agency (EPA) weighs decisions about air pollution regulations, it typically selects candidate actions from one or more sectors, such as electric power generation and industry. For each strategy considered, the agency carefully estimates the costs and benefits, then decides which actions to pursue.
We study air pollution and options for reducing it. In a newly published study, we flipped the traditional approach around by starting with the goal of finding emission control actions, among all sources, that could save a specified number of lives for the lowest cost. In doing so, we identified a set of low-cost actions to reduce air pollutant emissions from highly polluting industrial and residential sources, such as residential wood-burning furnaces, that can provide highly cost-effective health benefits.
The U.S. has made tremendous progress in reducing air pollution since 1990, and this has produced significant public health improvements. But air pollution still imposes a serious health burden on the U.S. population, and there are signs that past progress in improving air quality may now be leveling off. New ways of analyzing actions to control air pollution and its health impacts can help.
The number of bad air days in 35 major U.S. cities has plateaued since 2013. U.S. EPA
An Alternative Approach
Under the 1970 Clean Air Act, it is the EPA's job to set National Ambient Air Quality Standards. These regulations limit concentrations of six major air pollutants that harm public health and the environment. Then each state adopts actions that will meet these standards, such as reducing emissions from power plants or large industries.
The EPA also sets limits on emissions from some specific sources over which it has legal authority, including new power plants and motor vehicles. In doing so, the agency aims for air that is considered healthy for all Americans to breathe.
For each strategy considered, the EPA often runs a full cost-benefit analysis. This approach requires a complex atmospheric model to estimate how each proposed action will affect air pollutant concentrations, and the health impacts that will result. This limits the number of options that can be considered.
Our study focused on fine particulate matter, known as PM2.5. We created a framework that simplified the complexity of the atmosphere and air pollution's health impacts. For each U.S. state we calculated impact factors, which represent deaths related to PM2.5 exposure per ton of emissions of different chemical components from different sources. Then we fed these impact factors into an economic model of the U.S. energy system, allowing the model to calculate deaths for any strategy.
Next we set a limit on total deaths caused by PM2.5, and let the model select the least expensive set of actions that would meet energy needs – an important factor because energy use is a major air pollution source – while keeping PM2.5-related deaths below our ceiling. Our model projected future scenarios to 2050, so we considered different ceilings at various points in time, and observed the actions the model selected.
This alternative approach has the advantage of considering a wide range of possible control strategies that affect many different sources. It prioritizes the actions that most cost-effectively reduce premature deaths. Further, by considering these actions in the context of the broader energy system, we can include actions like fuel switching and energy efficiency as alternatives, and quantify consequences of actions throughout the U.S. energy system.
High Particulate Emitters
Using this approach, we pinpointed a set of sources whose emissions contribute disproportionately to PM2.5 mortality impacts. They include factories and other industrial facilities powered by coal and oil, and wood-fired residential furnaces. Emissions from these sources are rising and may continue to increase in the future without additional controls.
Our model showed that reducing emissions from these sources – mainly by electrifying them – could cut projected national air pollution-related deaths in 2050 in half very cost-effectively. Overall national health benefits from these reductions would be roughly seven times the cost of the pollution controls. As many studies have found, air pollution controls tend to be very cost-effective because these emissions cause people to die prematurely through cardiovascular diseases, stroke, lung cancer and other long-term illnesses.
Our study shows that this approach would reduce PM2.5-related emissions in each state. Progress would be greatest in northern and eastern states, including Ohio and Pennsylvania. These regions have many large industrial sources and are densely populated, which means that many people benefit from cleaner air.
Ohio has the largest potential for cost-effectively reducing PM2.5 deaths through cutting industrial coal emissions. California would benefit most from controls on residential wood burning, and Texas would see the greatest reductions in emissions from large petrochemical industries.
We also found that these actions had little influence on overall energy usage in the U.S., and therefore little effect on greenhouse gas emissions. This was interesting because previous research has found that most initiatives to reduce greenhouse gases – which typically involve switching to less-polluting fuels, such as going from coal to natural gas to renewables – also reduce air pollutant emissions, with significant benefits for public health. But the opposite is not true: Low-cost air pollution controls do not appear to have a big influence on U.S. greenhouse gas emissions.
The costs and health benefits of identified low-cost actions to reduce projected national 2050 PM2.5-related deaths by 10% to 50%. Yang Ou, CC BY-ND
Looking Forward to Cleaner Air
Our approach finds the least-cost way of reducing the health impacts of fine particle pollution among all Americans. But it does not ensure that current standards will be met everywhere. One limitation of our method is that we analyzed emissions at the state level, but our current model does not permit us to look more closely at air quality and health impacts for individual urban areas within states that exceed fine particle standards.
Still, our methods offer another tool that the EPA and states can use to help in planning air quality improvements, and the actions identified as being cost-effective for improving health can be compared with those currently being pursued. Spotlighting alternative pollution reduction options can help federal and state regulators make decisions about energy resources and their environmental and health impacts for the coming decades.
As natural gas and renewable energy prices fall, energy industries are in the midst of a transition driven by new technologies and changing economics. As this shift takes place, it is important to consider how to meet new energy demands while reducing greenhouse emissions and the health impacts of air pollutants. We hope our methods will be useful in informing these decisions in the U.S. and elsewhere.
Inefficient wood stoves and wood-burning furnaces are major fine particle sources. Madison & Dane County Public Health
Jason West is a professor of environmental sciences and engineering at the University of North Carolina at Chapel Hill.
Yang Ou is a postdoctoral associate at the Pacific Northwest National Laboratory.
Disclosure statements: Jason West receives funding from the EPA, NASA, NSF, the Donald and Jennifer Holzworth Faculty Acceleration Fund in Climate Change, and the State of North Carolina.
Yang Ou was supported by the Research Participation Program at the Center for Environmental Measurement and Modeling, U.S. Environmental Protection Agency, administered by the Oak Ridge Institute for Science and Education (ORISE).
Reposted with permission from The Conversation.
- Trump Administration Removes Federal Database That Tracked ... ›
- Half of U.S. Air Pollution Deaths Linked to Out-of-State Emissions ... ›
EcoWatch Daily Newsletter
Mangroves play a vital role in capturing carbon from the atmosphere. Mangrove forests are tremendous assets in the fight to stem the climate crisis. They store more carbon than a rainforest of the same size.
- Protecting Mangroves Can Prevent Billions of Dollars in Global ... ›
- Could the 'Mangrove Effect' Save Coasts From Sea Level Rise ... ›
Monday is World Oceans Day, but how can you celebrate our blue planet while social distancing?
- 5 Things to Know About Earth's Warming Oceans - EcoWatch ›
- Bioluminescent Waves Mesmerize California Beachgoers, Surfers ... ›
- NOAA: 2020 Could Be Warmest Year on Record - EcoWatch ›
- On June 8, We Celebrate Our Oceans, Our Future - EcoWatch ›
- 5 Things to Know About the State of Our Oceans for World Oceans Day ›
By Jacob L. Steenwyk and Antonis Rokas
From the mythical minotaur to the mule, creatures created from merging two or more distinct organisms – hybrids – have played defining roles in human history and culture. However, not all hybrids are as fantastic as the minotaur or as dependable as the mule; in fact, some of them cause human diseases.
When Looking Through a Microscope Isn’t Close Enough.<p>For the last few years, <a href="http://www.rokaslab.org/" target="_blank">our team at Vanderbilt University</a>, <a href="https://www.researchgate.net/lab/Gustavo-Goldman-Lab" target="_blank">Gustavo Goldman's team at São Paulo University in Brazil</a> and many other collaborators around the world have been collecting samples of fungi from patients infected with different species of <em>Aspergillus</em> molds. One of the species we are particularly interested in is <a href="https://doi.org/10.1006/rwgn.2001.0082" target="_blank"><em>Aspergillus nidulans</em>, a relatively common and generally harmless fungus</a>. Clinical laboratories typically identify the species of <em>Aspergillus</em> causing the infection by examining cultures of the fungi under the microscope. The problem with this approach is that very closely related species of <em>Aspergillus</em> tend to look very similar in their broad morphology or physical appearance when viewing them through a microscope.</p><p>Interested in examining the varying abilities of different <em>A. nidulans</em> strains to cause disease, we decided to analyze their total genetic content, or genomes. What we saw came as a total surprise. We had not collected <em>A. nidulans</em> but <em>Aspergillus latus</em>, a close relative of <em>A. nidulans</em> and, as we were to soon find out, <a href="https://doi.org/10.1016/j.cub.2020.04.071" target="_blank">a hybrid species that evolved through the fusion of the genomes</a> of two other <em>Aspergillus</em> species: <em>Aspergillus spinulosporus</em> and an unknown close relative of <em>Aspergillus quadrilineatus</em>. Thus, we realized not only that these patients harbored infections from an entirely different species than we thought they were, but also that this species was the first ever <em>Aspergillus</em> hybrid known to cause human infections.</p>
Several Different Fungal Hybrids Cause Human Disease.<p>Hybrid fungi that can cause infections in humans are well known to occur in several different lineages of single-celled fungi known as yeasts. Notable examples include multiple different species of <a href="https://doi.org/10.1002/yea.3242" target="_blank">yeast hybrids</a> that cause the human diseases <a href="https://rarediseases.info.nih.gov/diseases/6218/cryptococcosis" target="_blank">cryptococcosis</a> and <a href="https://www.cdc.gov/fungal/diseases/candidiasis/index.html" target="_blank">candidiasis</a>. Although pathogenic yeast hybrids are well known, our discovery that the <em>A. latus</em> pathogen is a hybrid is a first for molds that cause disease in humans.</p>
(Left) Candida yeasts live on parts of the human body. Imbalance of microbes on the body can allow these yeasts, some of which are hybrids, to grow and cause infection. (Right) Cryptococcus yeasts, including ones that are hybrids, can cause life-threatening infections in primarily immunocompromised people. Centers for Disease Control and Prevention<p><a href="https://doi.org/10.1371/journal.ppat.1008315" target="_blank">Why certain <em>Aspergillus</em> species are so deadly</a> while others are harmless remains unknown. This may in part be because <a href="https://doi.org/10.1016/j.fbr.2007.02.007" target="_blank">combinations of traits, rather than individual traits</a>, underlie organisms' ability to cause disease. So why then are hybrids frequently associated with human disease? Hybrids inherit genetic material from both parents, which may result in new combinations of traits. This may make them more similar to one parent in some of their characteristics, reflect both parents in others or may differ from both in the rest. It is precisely this mix and match of traits that hybrids have inherited from their parental species that <a href="https://www.nytimes.com/2010/09/14/science/14creatures.html" target="_blank">facilitates their evolutionary success</a>, including their ability to cause disease.</p>
The Evolutionary Origin of an Aspergillus Hybrid.<p>Multiple evolutionary paths can lead to the emergence of hybrids. One path is through mating, just as the horse and donkey mate to create a mule. Another path is through the merging or fusion of genetic material from cells of different species.</p><p>It is this second path that appears to have been taken by our fungus. <em>A. latus</em> appears to have two of almost everything compared to its parental species: twice the genome size, twice the total number of genes and so on. But unlike other hybrids, which are often sterile like the mule, we found that <em>A. latus</em> is capable of reproducing both asexually and sexually.</p><p>But how distinct were the parents of <em>A. latus</em>? By comparing the parts contributed by each parent in the <em>A. latus</em> genome, we estimate that its parents are approximately 93% genetically similar, which is about as related as we humans are with lemurs. In other words, <em>A. latus</em>, an agent of infectious disease, is the fungal equivalent of a human-lemur hybrid.</p>
How A. Latus Differs From its Parents.<p>Elucidating the identity of closely related fungal pathogens and how they differ from each other in infection-relevant characteristics is a key step toward reducing the burden of fungal disease. For example, we found that <em>A. latus</em> was three times more resistant than <em>A. nidulans</em>, the species it was originally identified as using microscopy-based methods, to one of the most common antifungal drugs, <a href="https://www.drugbank.ca/drugs/DB00520" target="_blank">caspofungin</a>. This result provides a clear example of the potential importance of accurate identification of the <em>Aspergillus</em> pathogen causing an infection.</p><p>We also examined how <em>A. latus</em> and <em>A. nidulans</em> interact with cells from our immune system. We found that immune cells were less efficient at combating <em>A. latus</em> compared to <em>A. nidulans</em>, suggesting the hybrid fungus may be trickier for our immune systems to identify and destroy.</p><p>In the midst of the COVID-19 pandemic, our quest to understand <em>Aspergillus</em> pathogens is becoming more urgent. Growing evidence suggests that <a href="https://doi.org/10.1111/myc.13096" target="_blank">a fraction of COVID-19 patients are also infected with <em>Aspergillus</em>.</a> More worrying is that these <a href="https://doi.org/10.3201/eid2607.201603" target="_blank">secondary <em>Aspergillus</em> infections</a> can worsen the clinical outcomes for those infected with the novel coronavirus. That being said, we stress that little is known about <em>Aspergillus</em> infections in COVID-19 patients due to a lack of systematic testing, and none of the infections identified so far appear to have been caused by hybrids.</p><p>So, when it comes to hybrids, some are fantastic (the minotaur), some are helpful (the mule) and some are dangerous (<em>Aspergillus latus</em>). Understanding more about the biology of <em>Aspergillus latus</em> may help in our understanding of how microbial pathogens arise and how to best prevent and combat their infections.</p>
This Saturday, June 6, marks National Trails Day, an annual celebration of the remarkable recreational, scenic and hiking trails that crisscross parks nationwide. The event, which started in 1993, honors the National Trail System and calls for volunteers to help with trail maintenance in parks across the country.
- As Protests Rage, Climate Activists Embrace Racial Justice ... ›
- First-Ever Black Birders Week Tackles Racism Outdoors - EcoWatch ›
- 15 EcoWatch Stories on Environmental and Racial Injustice ... ›
- Take a Hike Day Is Around the Bend. What's Your Dream Hike ... ›
By John Letzing
This past Wednesday, when some previously hard-hit countries were able to register daily COVID-19 infections in the single digits, the Navajo Nation – a 71,000 square-kilometer (27,000-square-mile) expanse of the western US – reported 54 new cases of what's referred to locally as "Dikos Ntsaaígíí-19."
The Navajo Nation covers the corners of three different states. Google Maps
Growing Contribution<img lazy-loadable="true" src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzM3NDY5Ny9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTY0NjM4MTgyM30.IuQTKQs1stvYYKD6vaVTrqAyoBsUG0BhDvlhxsyKwPA/img.png?width=980" id="02a05" class="rm-shortcode" data-rm-shortcode-id="2841f82b1785df5d5ed7bf64d3bb882b" data-rm-shortcode-name="rebelmouse-image" />
World Economic Forum
- Black and Hispanic Americans Suffer Disproportionate Coronavirus ... ›
- Native American Tribes' Pandemic Response Is Hindered by ... ›
- Navajo Nation Has Highest Covid-19 Infection Rate in the U.S. ... ›
World Environment Day: A Time to Consider the Planet We’ll Return To, and Decide How to Care for It Going Forward
It's a different kind of World Environment Day this year. In prior years, it might have been enough to plant a tree, spend some extra time in the garden, or teach kids the importance of recycling. This year we have heavier tasks at hand. It's been months since we've been able to spend sufficient time outside, and as we lustfully watch the beauty of a new spring through our kitchen's glass windows, we have to decide how we'll interact with the natural world on our release, and how we can prevent, or be equipped to handle, future threats against our wellbeing.
Scuba divers around the world are holding their metaphorical breath to see if a coronavirus infection affects the ability to dive.
DAN medical experts explained the difference between normal lungs, on the left, and "very serious lungs caused by COVID-19," on the right. Matias Nochetto / Divers Alert Network (DAN)
- How the COVID-19 Coronavirus Attacks the Entire Body - EcoWatch ›
- What Does 'Recovered From Coronavirus' Mean? - EcoWatch ›
- Scuba Divers Make Face Masks out of Recycled Ocean Plastic ... ›