Study predicts major rise in deaths due to extreme temperatures and air pollution

Posted on November 22, 2024 by Respro® UK Ltd

New study projects a sharp rise in temperature- and pollution-related mortality, with the impact of temperature surpassing that of pollution for a fifth of the global population.

Mortality attributable to air pollution and extreme temperatures is a major concern,  and it is expected to heighten in the future. In a new study led by the Max Planck Institute for Chemistry, an international research team found that, under the most probable projection, annual mortality rates linked to air pollution and extreme temperatures could reach 30 million by the end of the century. The research, based on advanced numerical simulations, suggests a concerning trend:  pollution-related deaths are expected to increase five-fold, while temperature-related mortality could rise seven-fold, posing a more critical health risk than air pollution for at least 20% of the world’s population.

The researchers base their calculations on projections from 2000 to 2090, analyzed in ten-year intervals. “In 2000, around 1.6 million people died each year due to extreme temperatures, both cold and heat. By the end of the century, in the most probable scenario, this figure climbs to 10.8 million, roughly a seven-fold increase. For air pollution, annual deaths in 2000 were about 4.1 million. By the century’s close, this number rises to 19.5 million, a five-fold increase,” explains Dr. Andrea Pozzer, group leader at the Max Planck Institute for Chemistry in Mainz and adjunct associate professor at The Cyprus Institute in Nicosia, Cyprus.

The study shows significant regional differences in future mortality rates. South and East Asia are expected to face the strongest increases, driven by aging of the population, with air pollution still playing a major role. In contrast, in high-income regions-; such as Western Europe, North America, Australasia, and Asia Pacific-;deaths related to extreme temperatures are expected to surpass those caused by air pollution. In some countries within these regions, such as the United States, England, France, Japan and New Zealand, this shift is already occurring. The disparity is likely to grow, with extreme temperatures becoming a more significant health risk than air pollution also in countries of Central and Eastern Europe (e.g., Poland and Romania) and parts of South America (e.g., Argentina and Chile).

By the end of the century, temperature-related health risks are expected to outweigh those linked to air pollution for a fifth of the world’s population, underscoring the urgent need for comprehensive actions to mitigate this growing public health risk.

“Climate change is not just an environmental issue; it is a direct threat to public health,” says Andrea Pozzer. “These findings highlight the critical importance of implementing decisive mitigation measures now to prevent future loss of life”, adds Jean Sciare, director of the Climate and Atmosphere Research Center (CARE-C) of The Cyprus Institute, key contributor to the study.

Source:

Max Planck Institute for Chemistry

Study predicts major rise in deaths due to extreme temperatures and air pollution
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New study finds air pollution increases inflammation primarily in patients with heart disease

Posted on November 19, 2024 by Respro® UK Ltd

A new study by heart researchers at Intermountain Health in Salt Lake City finds that patients with heart disease, specifically those with heart failure, are especially vulnerable to the impacts of air pollution and poor air quality and can take steps to protect themselves.

Results from the Intermountain Health study, presented at the American Heart Association’s 2024 Scientific Sessions international conference in Chicago, found that two inflammatory markers—CCL27 (C-C motif chemokine ligand 27) and IL-18 (interleukin 18)—were elevated in heart failure patients who were exposed to poor air quality, but did not change in those without heart disease.

This indicates that such air pollution events put more strain on the bodies of patients who already have heart problems.

While previous research has shown that people with some chronic health conditions, like heart failure, coronary disease, asthma, and COPD, struggle during spikes in air pollution, the new Intermountain Health study demonstrates that cardiac inflammation levels specifically rise in people with heart disease during periods of poor air quality.

“These biomarkers rose in response to air pollution in people who already had heart disease, but not in patients who were heart disease free, showing that heart failure patients are not as able to adapt to changes in the environment,” said Benjamin Horne, Ph.D., principal investigator of the study and professor of research at Intermountain Health.

For the retrospective study, Intermountain Health researchers worked with scientists at Stanford University and the Harvard School of Public Health to examine the blood of patients enrolled in the Intermountain INSPIRE registry, which collects blood and other biological samples, medical information and laboratory data from healthy individuals and those who have been diagnosed with a variety of medical conditions.

Researchers specifically looked at blood tests for 115 different proteins that are signs of increased inflammation in the body.

They then examined blood draws of 44 patients with heart failure with preserved ejection fraction, and 35 people without heart disease. Some blood was drawn on days with low air pollution, where ambient PM2.5 levels were under 7 micrograms per cubic meter (μg/m3) of air; those test results were compared to draws done in other people on days when air pollution spiked to PM2.5 levels of 20 μg/m3 or over.

These spikes were caused by either wildfire smoke in the summer, or during a winter inversion, where air pollution is trapped when warm air holds pollution closer to the ground.

Researchers found that two inflammatory markers—CCL27 and IL-18—were elevated in heart failure patients, but did not change in those without heart disease, indicating that such air pollution events put more strain on the bodies of patients who already have heart problems.

These findings “give us some information about mechanisms in people with heart failure who are having inflammation and suggest they’re not as capable in responding to acute inflammation as people who are healthy,” said Dr. Horne.

He added that the results from the study suggest that heart failure patients need to take extra precautions during times when air pollution is high.

“It’s important that individuals with known heart disease, including those diagnosed with heart failure, need to be especially cautious during periods of poor air quality. This includes exercising indoors, making sure to take their prescribed medications, and avoiding areas like roadways and highways where there’s a lot more traffic and pollution,” he said.

New study finds air pollution increases inflammation primarily in patients with heart disease
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Delhi’s air pollution turns ‘severe’ as temperatures, wind speeds drop

Posted on November 14, 2024 by Respro® UK Ltd

Air pollution in India’s national capital increased to ‘severe’ on an official index on Wednesday for the first time this season as temperatures and wind speeds dropped, reducing visibility and affecting some flights.

Delhi overtook Pakistan’s Lahore as the world’s most polluted city in Swiss group IQAir’s live rankings, and India’s pollution control authority said the national capital territory’s 24-hour air quality index (AQI) score had touched 418.

The Central Pollution Control Board defines an AQI reading of 0-50 as “good”, and above 401 as “severe”, which affects healthy people and “seriously impacts” those with existing diseases.

The Indian capital battles smog – a toxic mix of smoke and fog – every winter as cold air traps dust, emissions, and smoke from illegal farm fires.

Authorities have on occasion closed schools, stopped some building work, and placed restrictions on private vehicles to curb the problem.

Pakistan’s Punjab province, which shares a border with India and is also battling toxic air, has this month banned outdoor activities, closed schools and ordered some shops, markets, and malls to close early.

The concentration of PM2.5 – particulate matter measuring 2.5 microns or less in diameter that can be carried into lungs, causing deadly diseases and cardiac issues – in Delhi was more than 120 times the World Health Organisation’s recommended levels on Wednesday morning, IQAir said.

Weather department officials also blamed the smog, which reduced visibility to zero in some places, on high humidity, low wind speed, and the minimum temperature dropping to 17 degrees Celsius (63 degrees Fahrenheit) from 17.9 C a day before.

At least eight flights were diverted from the city’s Indira Gandhi International Airport, news agency ANI reported.

Dense fog – defined as that which reduces visibility to 50-200 metres (164-657 ft) – was expected to continue over northwest India for the “next 2-3 days”, the India Meteorological Department said.

Delhi’s air pollution turns ‘severe’ as temperatures, wind speeds drop | Reuters
https://www.reuters.com/world/india/visibility-drops-parts-delhi-pollution-surges-2024-11-13/
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Almost a third of asthma cases are attributable to long-term exposure to fine particular matter, global study suggests

Posted on October 29, 2024 by Respro® UK Ltd

Drawing on evidence involving about 25 million people worldwide, an international research team led by the Max Planck Institute for Chemistry demonstrates that long-term exposure to ambient PM2.5 significantly increases the risk of asthma, affecting both children and adults. The researchers find that approximately 30% of new asthma cases worldwide were linked to fine particulate matter (PM2.5) exposure, highlighting the dramatic threat air pollution poses to public health.

Asthma is currently an incurable disease that severely impairs quality of life, with recurring symptoms such as wheezing, coughing, and shortness of breath. As of today, about 4% of the world’s population suffers from asthma, with more than 30 million new cases arising annually.

Evidence suggests that long-term exposure to air pollution of fine particulate matter (PM2.5) is an important risk factor for developing asthma. However, inconsistencies in findings from earlier epidemiological studies have left this potential health risk open to debate, as some studies observed an increased risk while others found no association.

To resolve this controversy, Dr. Ruijing Ni, the first author of the study published in the journal One Earth, and her colleagues at the Max Planck Institute for Chemistry have conducted a comprehensive global meta-analysis with researchers from China, the U.S., and Australia.

The research team determined the data from 68 epidemiological studies from 2019 conducted across 22 countries, including those in North America, Western Europe, East Asia, South Asia, and Africa. They conclude that there is now sufficient evidence with high confidence level to support an association between long-term exposure to ambient PM2.5 and asthma.

11% of new cases of asthma in Germany are attributable to particulate matter

“We estimate that globally in 2019, almost a third of asthma cases are attributable to long-term PM2.5 exposure, corresponding to 63.5 million existing cases and 11.4 million new cases. In Germany, the pollution may have been responsible for 11% of new asthma cases, which corresponds to 28,000 people. We also find that the risk of asthma associated with PM2.5 is much higher in children than in adults, reflecting the age-related vulnerability,” says Dr. Ni.

Typically, the full maturation of lung and immune function is gradually completed until early adulthood. As a result, children may be more susceptible to air pollution exposure, which can lead to airway oxidative stress, inflammation, and hyper-responsiveness, as well as changes in immunological responses and respiratory sensitization to allergens. All these factors play a role in the development of asthma.

Further using these data, the research team established exposure-response curves for both childhood and adult asthma. Such curves are widely employed to quantitatively assess health risks by illustrating the relationship between the level of exposure to a particular substance, e.g., PM2.5 and the magnitude of the effect it produces, e.g., asthma risk.

The exposure-response curves were determined by incorporating evidence from countries and regions across various income levels, which capture the global variation in PM2.5 exposure. “This initiative is important for quantifying global health effects of air pollution,” comments Prof. Yuming Guo, an epidemiologist from Monash University.

Countries with different income levels and particulate matter pollution considered

Populations in low- and middle-income countries (LMICs) are typically exposed to higher concentrations of air pollution and bear a greater burden of PM2.5. In contrast, research on the health effects of PM2.5 has been limited in these regions previously, with the majority of studies conducted in North America and Western Europe.

Consequently, attempting a global health impact assessment of PM2.5 exposure necessitates extrapolating exposure-response associations observed in high-income countries to LMICs. The approach may introduce large uncertainty due to the differences in air pollution sources, health care systems, and demographic characteristics between high-income countries and LMICs.

The inclusion of evidence from several LMICs mitigates the limitation in approach and enables the exposure-response curves to be applicable to assess city- to global-scale attributable burden of asthma, as well as asthma health benefits associated with air pollution reductions, e.g., health benefits obtained from policy-driven reductions in air pollution under different scenarios.

“Our findings highlight the urgent need for policymakers to enforce stringent legislation to continuously combat air pollution, while personal protective measures, such as wearing masks, can also help reduce individual exposure and mitigate the risk of asthma,” emphasizes Prof. Yafang Cheng, the corresponding author of the study and the director at the Max Planck Institute for Chemistry.

The study was conducted by researchers from the Max Planck Institute for Chemistry (Germany), the Institute of Atmospheric Physics at the Chinese Academy of Sciences (China), University of Washington (U.S.), and Monash University (Australia).

Almost a third of asthma cases are attributable to long-term exposure to fine particular matter, global study suggests
https://phys.org/news/2024-10-asthma-cases-attributable-term-exposure.html
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Air pollution linked to higher risk of infertility in men

Posted on September 5, 2024 by Respro® UK Ltd

Long term exposure to fine particulate matter (PM2.5) air pollution is linked to a higher risk of infertility in men, whereas road traffic noise is linked to a higher risk of infertility in women over 35, finds a Danish study published by The BMJ.

If these findings are confirmed in future studies, they could help guide strategies to regulate noise and air pollution to protect the general population from these exposures, say the researchers.

Infertility is a major global health problem affecting one in seven couples trying to conceive.

Several studies have found negative links between particulate air pollution and sperm quality and success after fertility treatment, but results on fecundability (the likelihood of conceiving) are inconsistent, and no studies have investigated the effects of transport noise on infertility in men and women.

To address this uncertainty, researchers set out to investigate whether long term exposure to road traffic noise and fine particulate matter (PM2.5) air pollution was associated with a higher risk of infertility in men and women.

Their findings are based on national registry data for 526,056 men and 377,850 women aged 30–45 years, with fewer than two children, cohabiting or married, and residing in Denmark between 2000 and 2017.

This group was selected to include a high proportion of people actively trying to become pregnant, and thus at risk of an infertility diagnosis. Individuals with an existing infertility diagnosis were excluded, as were women who had undergone surgery that prevents pregnancy and men who were sterilized.

Yearly average PM2.5 concentrations and road traffic noise levels at each participant’s address (1995–2017) were calculated, and infertility diagnoses were recorded from the national patient register.

Infertility was diagnosed in 16,172 men and 22,672 women during an 18-year follow-up period (average of just over 4 years).

After adjusting for several potentially influential factors including income, education level, and occupation, exposure to 2.9 µg/m3 higher average levels of PM2.5 over five years was associated with a 24% increased risk of infertility in men aged 30-45 years. PM2.5 was not associated with infertility in women.

Exposure to 10.2 decibels higher average levels of road traffic noise over five years was associated with a 14% increased risk of infertility among women older than 35 years. Noise was not associated with infertility among younger women (30–35 years).

In men, road traffic noise was associated with a small increased risk of infertility in the 37-45 age group, but not among those aged 30-37 years.

The higher risk of noise related infertility in women and PM2.5 related infertility in men was consistent across people living in rural, suburban, and urban areas as well as across people with low, medium, and high socioeconomic status.

This is an observational study, so it can’t establish cause, and the researchers acknowledge that couples not trying to conceive may have been included, and that information on lifestyle factors and exposure to noise and air pollution at work and during leisure activities was lacking.

However, this was a large study based on reliable health and residential data that used validated models to assess pollution and noise levels, and the researchers were able to account for a range of important social and economic factors.

As such, they conclude, “If our results are confirmed in future studies, it suggests that political implementation of air pollution and noise mitigations may be important tools for improving birth rates in the Western world.”

More information: Long term exposure to road traffic noise and air pollution and risk of infertility in men and women: nationwide Danish cohort study, The BMJ (2024). DOI: 10.1136/bmj-2024-080664

Journal information: British Medical Journal (BMJ) 

Air pollution linked to higher risk of infertility in men

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Exposure to Wildfire Smoke Greatly Raises Risk of Dementia Diagnosis

Posted on July 30, 2024 by Respro® UK Ltd

Key Takeaways

  • Wildfire smoke may be particularly hazardous to brain health, according to a 10-year study of more than 1.2 million southern Californians.
  • Exposure to wildfire smoke increases the risk of being diagnosed with dementia more than other forms of air pollution.
  • The risk of exposure to fine particulate matter (PM2.5) air pollution is much more pronounced when the source is wildfire smoke than when it comes from other sources, such as motor vehicles and factories.
  • To lower their risk, people should update their home air filtration systems when possible, stay inside when the air quality is unhealthy, and wear an N95 mask outside when the Air Quality Index reaches 100.

Exposure to wildfire smoke increases the risk of being diagnosed with dementia more than other types of air pollution, according to a decade-long study of more than 1.2 million people in southern California. The findings, reported today at the Alzheimer’s Association International Conference® (AAIC®) 2024, in Philadelphia and online, suggest the brain health threat posed by wildfire smoke is higher than other forms of air pollution.

Wildfire smoke, motor vehicles and factories all emit a type of air pollution called fine particulate matter (PM2.5). This is a microscopic mixture of solid and liquid droplets in the air that are 30 times smaller than the width of an average human hair. Researchers found that the risk of dementia diagnosis due to exposure to PM2.5 in wildfire smoke was notably stronger — even with less exposure — than the risk due to the other sources of PM2.5 air pollution. Exposure to non-wildfire PM2.5 raised the risk of dementia diagnosis, but not as much as wildfire smoke.

High levels of PM2.5 also have been shown to raise the risk of heart disease, asthma and low birth weight.

“With the rising global incidence of wildfires, including in California and the western U.S., exposure to this type of air pollution is an increasing threat to brain health,” said Claire Sexton, DPhil, Alzheimer’s Association senior director of scientific programs and outreach. “These findings underscore the importance of enacting policies to prevent wildfires and investigating better methods to address them.”

Researchers analyzed the health records of 1,227,241 socioeconomically diverse Kaiser Permanente southern California members who were 60 years or older between 2009-2019, none of whom had been diagnosed with dementia at the beginning of the study. Total PM2.5 was estimated from various sources, including satellite-derived aerosol properties and Environmental Protection Agency monitoring. Researchers used air quality monitoring data, satellite imagery and machine learning techniques to separate wildfire and non-wildfire PM2.5. They determined each study participant’s exposure to both sources of PM2.5 according to where they lived. They compared that information to subsequent diagnoses of dementia in participants’ health records.

Reported for the first time at AAIC 2024, the researchers observed a 21% increase in the odds of dementia diagnosis for every increase of 1 microgram per meter — or µg/m3, which is the amount of particulate matter in a cubic meter of air — in the three-year average wildfire PM2.5 exposure. Comparatively, they determined study participants had a 3% increased risk of dementia diagnosis for every increase of 3 µg/m3 in the three-year average of non-wildfire PM2.5 exposure.

“Previous research has found that exposure to PM2.5 is associated with dementia, but in light of our large, long-term study, it’s apparent the risk from exposure due to wildfire smoke is an even bigger concern,” said Holly Elser, M.D., Ph.D., the study’s first author and a neurology resident at the Hospital of the University of Pennsylvania, Philadelphia. “Air pollution produced by wildfires now accounts for more than 70% of total PM2.5 exposure on poor air quality days in California. This is a real problem.”

Dr. Elser noted several reasons why PM2.5 produced by wildfires might be more hazardous to health: they are produced at higher temperatures, contain a greater concentration of toxic chemicals and, on average, are smaller in diameter than PM2.5 from other sources. She said more research needs to be done to determine the exact mechanisms.

“The findings appeared most pronounced among individuals from racially and ethnically minoritized groups and in high poverty areas,” said Joan A. Casey, Ph.D., senior author of the study and assistant professor in the Department of Environmental and Occupational Health Sciences at the University of Washington, Seattle. “These findings underscore that clinical and health policies seeking to prevent dementia-associated disparities should include efforts to reduce exposure to long-term wildfire and non-wildfire PM2.5.”

Drs. Elser and Casey recommend that people update their air filtration systems and check the air quality on their weather app if they use one. An Air Quality Index (AQI) number of 100 or higher means the air is unhealthy to breathe. To reduce their risk when the AQI is 100 or higher, people should stay inside when possible and close the windows, and wear an N95 mask when they go outside.

Exposure to Wildfire Smoke Raises Risk of Dementia | alz.org

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Large-scale and intense wildfires carrying smoke across northern hemisphere

Posted on July 23, 2024 by Respro® UK Ltd

Late spring and early summer blazes in Canada, Alaska and eastern Russia add to carbon emissions


The northern hemisphere has had a large number of intense wildfires in the first half of summer, carrying vast amounts of smoke across Eurasia and North America.

Research by the Copernicus Atmosphere Monitoring Service (Cams) showed large-scale and intense wildfires had been developing throughout the late spring and summer, with numerous fires burning in Canada, Alaska and eastern Russia.

These wildfires are generally caused by long periods of hot and dry conditions in areas of high vegetation, and have resulted in increased carbon and smoke emissions. Smoke has also begun to extend much farther north, reaching across the Arctic Ocean to the high Arctic.

Emissions from Russian wildfires in June and July were higher than for the preceding two years, and fires in the region of Amur Oblast led to the estimated release of 17.2 megatonnes of carbon for the two-month period, the highest in 22 years.

Canada has also had some of its highest totals on record, with total carbon emissions of 11.1 megatonnes and 13.2 megatonnes for British Columbia and Alberta respectively across June and July.

Mark Parrington, a senior scientist at Cams, said: “We have been closely monitoring boreal fires in Cams over a number of years and noted some particularly extreme wildfire emissions and atmospheric impacts during that time, particularly in Canada, eastern Russia and the Arctic.”

Increasing wildfire activity is a major factor in these rising smoke emissions.

Guillermo Rein, a professor of fire science in the department of mechanical engineering at Imperial College London, said: “In recent years the fire season is expanding, starting earlier and lasting longer. But it’s not just the fact the wildfire season is widening, it’s also that the intensity of wildfire season is becoming unprecedented.”

According to official Russian figures, the number of wildfires this year has decreased by 30% compared with the previous year, but the area burnt is 50% larger, highlighting the intensity of the wildfires.

These increased smoke emissions have led to very high levels of air pollution and can lead to various health complications.

“In the short term, the most obvious complications are to respiratory systems, proving particularly dangerous for people that have underlying conditions like asthma, heart disease and lung disease,” says Dr Marina Romanello, a research fellow at the UCL Institute for Global Health.

“However, as the incidence of wildfires is increasing, people are being repeatedly exposed to acute levels of wildfire related air pollution, increasing their risk of developing chronic conditions like cardiovascular disease and cancer.”

Concentrations of very small harmful particulates in the smoke, known as PM2.5, have been found to be several times higher than the World Health Organization’s recommended 24-hour mean exposure threshold across a widespread region that includes eastern Mongolia, north-eastern China and northern Japan.

Romanello said: “PM2.5 particles are … able to go very deep into the lungs, past the lung-blood barrier, and enter the bloodstream, making these high levels of smoke emissions particularly concerning.”

While 2024’s estimated wildfire carbon emissions are very high so far, the season is still well short of the catastrophic 2023 season, when much of North America experienced record high levels of PM2.5.

Rein said: “We don’t think this season is going to break any records but it’s a strange situation where we’ve been seeing the worst in the records for so long that when you see it you think things are OK, when actually it’s still pretty bad.”

Large-scale and intense wildfires carrying smoke across northern hemisphere | Wildfires | The Guardian

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More Black Americans die from effects of air pollution, study shows

Posted on July 18, 2024 by Respro® UK Ltd

Everyone knows that air pollution is bad for health, but how bad depends a lot on who you are. People of different races and ethnicities, education levels, locations and socioeconomic situations tend to be exposed to different degrees of air pollution. Even at the same exposure levels, people’s ability to cope with its effects—by accessing timely health care, for example—varies.

A new study by Stanford Medicine researchers and collaborators, which takes into account both exposure to air pollution and susceptibility to its harms, found that Black Americans are significantly more likely to die from causes related to air pollution, compared with other racial and ethnic groups.

They face a double jeopardy: more exposure to polluted air along with more susceptibility to its adverse health effects because of societal disadvantages.

“We see differences across all factors that we examine, such as education, geography and social vulnerability, but what is striking is that the differences between racial-ethnic groups—partially due to our methodology—are substantially larger than for all of these other factors,” said Pascal Geldsetzer, MD, Ph.D., assistant professor of medicine and lead author of the study published July 1 in Nature Medicine.

The results demonstrate how air pollution can drive health inequities, contributing a large portion to the difference in mortality rates among different groups.

Yet, by the same token, the researchers say that reducing air pollution could be a powerful and achievable way to address these inequities.

Fine particles

Air quality throughout the U.S. has improved dramatically over the last few decades, thanks in large part to regulations such as the Clean Air Act, which sets limits on air pollutants emitted by industries and other sources.

Among the pollutants most linked to health, and the focus of the new study, is fine particulate matter, referred to as PM2.5 because it includes particles less than 2.5 micrometers in diameter. These particles are small enough to enter the bloodstream and affect vital organs.

“It’s very well recognized that PM2.5 is the biggest environmental killer globally,” said Tarik Benmarhnia, Ph.D., associate professor at the University of California, San Diego’s Scripps Institution of Oceanography and the senior author of the study.

Exposure to these fine particles can exacerbate asthma and chronic obstructive pulmonary disease in the short term, and in the long term contribute to heart disease, dementia, stroke and cancer.

In 1990, 85.9% of the U.S. population was exposed to average PM2.5 levels above 12 micrograms per cubic meter—the threshold set by the Environmental Protection Agency. In 2016, only 0.9% of the population was exposed to average levels above the threshold. (In February, the agency lowered the limit to 9 micrograms per cubic meter.)

Despite these significant improvements, not all communities have benefitted equally.

Benefits may vary

In the new study, the researchers wanted to see just how much PM2.5 levels contributed to mortality in people of different races and ethnicities, education, location (metropolitan or rural) and socioeconomic status.

They used existing county-level data on mortality along with census-tract-level data on PM2.5 air pollution and population from 1990 to 2016. They employed models derived from previous epidemiological studies, known as concentration-response functions, that linked certain deaths to air pollution levels. They chose a model that accounted for differences in susceptibility among racial and ethnic groups.

“Concentration-response functions are essentially saying, if you get exposed to this much more air pollution, then you would expect, on average, this much more risk of death,” Geldsetzer said.

Though deaths related to PM2.5 levels fell overall, some groups remained more affected than others. The researchers found higher rates of PM2.5-attributable mortality in people with less education; those living in large metropolitan areas; and those who were more socially vulnerable due to housing, poverty and other factors. People in the Mountain West states were less likely to die from PM2.5 pollution than people in other regions.

But the starkest disparities appeared when researchers sorted the data by race and ethnicity.

In 1990, the PM2.5-attributable mortality rate for Black Americans was roughly 350 deaths per 100,000 people, compared with less than 100 deaths per 100,000 people for each of the other races. By 2016, PM2.5-attributable mortality had fallen for all groups. Black Americans experienced the largest decline, to about 50 deaths per 100,000 people, yet were still the highest among all groups.

These relative trends were consistent throughout the country. In 96.6% of counties, Black Americans had the highest PM2.5-attributable mortality.

Among all the factors the researchers considered, race was the most influential in determining mortality risk from air pollution. They found that Black Americans have more exposure to air pollution, and its effects on mortality are amplified by factors such as poverty, existing medical conditions, more hazardous jobs, and lack of access to housing and health care.

Race and racism play into many of these amplifying factors, the researchers noted.

“Racism is an upstream driver of all these components of social inequality,” Benmarhnia said.

Taking action

“Air pollution is increasingly being recognized in public health as a cause of adverse health consequences that’s larger than people initially thought,” Geldsetzer said.

Harmful levels of PM2.5 can be imperceptible, but experienced day after day, year after year, they contribute to disease. And climate change means more wildfires (which produce particularly toxic fine particles) combined with extreme heat, increasing health risks.

“Even today there is a lot of resistance toward trying to reduce air pollution,” Benmarhnia said, citing the recent Supreme Court ruling against a plan to limit air pollution drifting across state lines.

Environmental policies should reduce air pollutants as much as possible, the researchers said, but also need to address the fact that some communities are more susceptible—something that major environmental organizations are not yet doing.

The silver lining is that the groups who suffer more from increasing air pollution would also benefit more from decreasing air pollution.

For every unit of reduction in PM2.5, for example, the associated mortality risk would decrease more for Black Americans than for other groups, helping close the racial gap.

“We want to emphasize how air pollution is a very good way to reduce health disparities, because it’s actionable,” Benmarhnia said. “We know we can do something about air pollution.”

More information: Pascal Geldsetzer et al, Disparities in air pollution attributable mortality in the US population by race/ethnicity and sociodemographic factors, Nature Medicine (2024). DOI: 10.1038/s41591-024-03117-0

Journal information: Nature Medicine 

More Black Americans die from effects of air pollution, study shows

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