Particulate matter, ozone, allergens ‘worsening with climate change’
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Key takeaways:
- Three environmental factors that have an impact on lung health are being worsened with events of climate change.
- Climate change sparks a domino effect of harmful events/conditions.
BOSTON — Amidst climate change, it is important that pulmonologists/critical care experts consider the impact worsening particulate matter, ozone and allergens have on their patients, according to a presentation at the CHEST Annual Meeting.
Vanessa Kerry, MD, MSc, critical care physician and director of the program in global public policy and social change in the department of global health and social medicine at Harvard Medical School, presented this idea at this year’s keynote address.
Kerry, also CEO and co-founder of Seed Global Health as well as the director general’s special envoy for climate change and health for WHO, highlighted these three factors to demonstrate how climate change plays a major role in lung health.
Air pollution, particulate matter
The first factor she addressed was air pollution and particulate matter.
Although air pollutants are especially harmful to patients with lung diseases/conditions, Kerry noted that they impact all individuals. According to her presentation slide, air pollution is behind 8.34 million deaths a year.
“What's happening is that the chemical species that lead to the degradation in air quality are frequently being co-emitted with greenhouse gasses,” Kerry said. “As we’re driving up temperatures from greenhouse gasses, we’re also emitting the factors that directly damage our lung health, be it nitric oxides, ozone or particulate matter.”
Other important environmental factors to consider within the context of air pollution are wildfires, droughts and increasing temperatures, Kerry said. As Healio previously reported, patients with asthma used reliever inhalers more on days with unhealthy air quality during the Canadian wildfires.
Notably, when looking at the entire world, individuals living in low- and middle-income countries are more frequently those who die due to long-term exposure to ambient particulate matter (PM2.5) and ozone, Kerry said.
“About 92% of all pollution-related deaths are being seen in those countries, but ... nowhere in the world is necessarily immune,” Kerry said.
A key player in high all-cause mortality attributable to air pollution is fossil fuels. During her presentation, Kerry emphasized this point by showed that removal of all fossil fuel emissions would lower these deaths by 85% in high-income countries. She also said that an even greater decrease in deaths due to air pollution in these countries would be seen if removal of all anthropogenic emissions took place (94%).
Encompassed within air pollution is particulate matter, which Kerry noted can be divided into three categories based on size/where it penetrates the lung: PM10 is 10 µm or less in diameter, PM2.5 is 2.5 µm or less in diameter and PM0.1 is 0.1 µm or less in diameter. As Healio previously reported, exposure to PM2.5 and PM10 was associated with a higher risk for respiratory ED visits.
“While all particulate matter of any size is a concern, the small diameter is particularly worrisome because it can penetrate deeply,” Kerry said.
To drive home the point that particulate matter is dangerous to the lungs, Kerry highlighted a study from 2019 analyzing exposure to PM10 and PM2.5 in adults from the U.K. Biobank.
“The study found that higher exposures to each pollutant were significantly associated with lower lung function and COPD,” Kerry said.
“There's no safe threshold level in any of this,” Kerry added. “The problem is that our particulate matter exposure is variable and not always in our control.”
When discussing how individuals have little control over air pollutant exposure, Kerry revisited wildfires and mentioned this disaster in the domino effect that comes with climate change.
“Climate change is increasing heat and drought, leading to the increased risk of wildfires, and smoke from wildfires create particulate matter, ozone and toxic gasses and chemicals, which are all linked to shortness of breath, asthma, COPD [and] have been associated with premature death in infants and low birth weight,” Kerry said.
As climate change continues to progress, Kerry brought up the need for policy changes and highlighted the U.S. Environmental Protection Agency (EPA) finalized change to the National Ambient Air Quality Standard for fine particulate pollution from 12 µg/m3 to 9 µg/m3 in February.
As Healio previously reported, the EPA wrote that this change will prevent up to 4,500 premature deaths, prevent 290,000 lost workdays and result in as much as $46 billion in net health benefits in 2032.
Ozone, allergens
Ozone is the second environmental factor that influences lung health and is being worsened because of climate change, Kerry said during her presentation.
“Ozone, as you well know, creates bronchial inflammation, airway hyperresponsiveness via oxidative injury and inflammation,” Kerry said.
A notable patient group that struggles when ground level ozone levels are high are those with COPD. According to Kerry, one of every nine COPD deaths globally is attributable to ozone.
“Seventy percent of those deaths are in India and China, so maybe not the United States because of dense urban populations, large populations and terrible air quality, but don’t kid yourself, those exist in our communities here, maybe not at countrywide scale, but certainly at a community level and a neighborhood scale, and probably is affecting your patients,” Kerry said.
Ozone also impacts asthma events, which Kerry highlighted through a study published in JAMA that tracked ozone and other air pollutant levels before, during and after the 1996 Olympics in Atlanta. During the 17-day Olympic Games period, researchers reported a 27.9% reduction in peak daily ozone concentrations and a 41.6% reduction in acute asthma care events.
“[These findings are] demonstrating the daily impact you can imagine that many of our patients have in the community from traffic or other gas emissions and the potential for us to reduce harm through strategic interventions,” Kerry said.
The third and final environmental factor outlined by Kerry as becoming worse with climate change is allergens.
As previously reported on Healio, climate change alters factors related to pollen and aeroallergens, leading to longer pollen seasons.
“Climate change is contributing to the potency of allergens,” Kerry said. “With more carbon dioxide in the air [and] warmer temperatures, plants are producing more pollen. We’re seeing them grow in more locations [and] flower over longer periods, so we’re having earlier and longer pollen seasons [and] higher pollen potency.”
Importantly, mold growth also goes hand in hand with climate change as climate change brings about more instances of wildfires, drought and flooding, Kerry said.
References:
- Doiron D, et al. Eur Respir J. 2019;doi:10.1183/13993003.02140-2018.
- Friedman MS, et al. JAMA. 2001;doi:10.1001/jama.285.7.897.