Story at a glance
- Air pollution is created when fuels are burned and release chemical compounds into the atmosphere.
- Research has shown that air pollutants can affect physical and mental health at low concentrations.
- Renewable energy has the potential to reduce emissions and lower air pollution levels.
Air pollution affects the health of everyone everywhere. The World Health Organization estimates that outdoor ambient air pollution caused 4.2 million deaths in 2016. While many of these deaths are in low- and middle-income countries, the health effects are felt by people all around the world.
Air pollution is created in part by burning fuel, which releases particles into the air. There are many types of compounds that can contaminate the air, including ozone and nitrous oxides. Once released into the atmosphere, it is difficult to mitigate the effects of the pollutants. Instead, a better strategy is to prevent emissions before they occur.
Greater use of renewable energy has the potential to reduce emissions and lower air pollution levels. For example, a study published in February in the journal Renewable Energy reports an analysis of hybrid energy systems that pull energy from fossil fuel-based sources, as well as renewable energy sources. For a case study of Iran, the researchers found that if renewable energy made up more than 72 percent of the energy system that would reduce CO2 emissions by 2000 kg per household annually.
If governments were to put in place policies to reach that proportion of renewable energy production, they could reach this target “very soon,” said the study’s first author Armin Razmjoo at the Universitat Politécnica de Catalunya in Spain in an email to The Hill.
The physical and mental health effects
Air pollution has been studied intensively for several decades, and the evidence for its negative effects on health has only grown.
“The more we look the more we see in terms of different health outcomes that are associated with air pollution and then also the health effects at low levels of air pollution,” said environmental epidemiologist Cathryn Tonne, an associate professor at ISGlobal, to The Hill.
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Some of the long-term health effects are directly related to inhalation of air pollution and particulate matter (PM), affecting the lungs. Researchers are also concerned about its effects on children, who because of their size are exposed to more pollution per surface area than adults.
“Initially, much of the research focused on the respiratory system, which as you know is quite intuitive that your lungs would be impacted by what you breathe in,” said Tonne. “It's associated with such an enormous range of health outcomes.”
It affects lung function and neurodevelopment, and in fetal development, it is also linked to preterm births. Other long-term health effects are related to the cardiovascular system, brain and even kidney function. A study published in 2018 in PLOS One found a connection between county level air pollution and prevalence of chronic kidney disease among the Medicare population.
Recent research has also tied air pollution levels to mental health and depression. For example, a study in Spain found links between increased air pollution concentration and increased odds of depression in a population over the span of five years. Other research has found links between increases in particulate matter and visits to the emergency room for mental health reasons.
Air pollution effects are really the most common diseases, says Tonne. You take diseases that are very common in a population and add air pollution, which leads to additional disease in the population. That's where you really see the big burden that’s attributable to air pollution.
Exposure to air pollution and other types of pollution are not equitable. “Exposure is dictated by race,” said author and ethicist Harriet Washington, who dives into environmental racism and its effects on African American communities in her book “A Terrible Thing to Waste.” “It's because of our social and political behavior over the centuries, a long history of relegating African Americans to only being able to live in certain places, and in places that were the least desirable for human habitation.”
We are seeing these health effects in Black communities and communities of color. Risk of death related to air pollution is higher among these populations, especially in men, Black people and people who are eligible for Medicaid, according to a study published in the New England Journal of Medicine. And environmental racism that increases exposure to pollution not only increases risk of mortality, it affects cognitive abilities and neurodevelopment, Washington discusses in her book.
On correlations and thresholds
Because of the nature of pollution exposure and how it is studied, much of what we know is based on correlations and long-term observational studies. But that does not make the evidence any less important.
“We've developed a bad habit as a culture, in minimizing the importance of correlation,” said Washington. “In fact, if this evidence comes from different sources and all points to the same risk factor that lends power to the correlation. Sometimes correlations are the best evidence we can get.”
We have to ask how powerful the correlations are, Washington said. If they are powerful enough to account for a good amount of the risk, “then that’s actionable, especially when considerate people's lives are being lost,” she said. “Sometimes these correlations tell us very powerfully that we have a source of injury.”
Many air pollution studies in recent years have focused on low-level exposure to air pollution, like that found in many areas in Europe and the U.S.
“They're looking at different health outcomes but almost universally find evidence of health effects at low levels of air pollution and in some cases really low levels of air pollution,” said Tonne. “So we're talking about Denmark, Sweden, parts of the US that have very, very low levels of air pollution.”
For example, a study in Gothenburg, Sweden, found associations between low levels of air pollution and ischemic heart disease in all participants and stroke in women. The air pollution concentrations were around 13 and 9 micrograms per cubic meter for PM10 and PM2.5.
There seems to be no threshold, no safe level of air pollution, says Tonne. And this is concerning because the way air quality is regulated is often based on thresholds.
Regulating for our health
Many current air pollution regulations have established thresholds for pollution concentrations and may also focus on specific geographic hotspots. What policies could do instead of focusing on thresholds or hotspots is to focus on “shifting the whole distribution of exposure in a population downwards,” said Tonne. Policy should focus not just in urban areas where you might have exceedances under the current standards, but also in rural areas where there's still important air pollution from agriculture and other sources.
Governments could choose to focus on incentivizing renewable energy. For example, Denmark has achieved 30 percent renewable energy. Germany has done even better at nearly 52 percent renewable energy during the first three months of 2020.
“There are some things we know to do that we simply aren't doing,” Washington said. “It's a staggering variety of ailments and incapacitation that is due to air pollution, and...we're not acting against it vigorously enough.”
A version of this story appeared on The Hill.
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