Preparing for Climate Change’s Impact on Allergies, Asthma

ORLANDO — It’s important for pediatricians not only to understand the causes and effects of climate change but also to know how to discuss this issue with families and make risk-based adjustments to their clinical practice based on the individual health and circumstances of each patient. That’s one of the key messages delivered on September 28 at the annual meeting of the American Academy of Pediatrics (AAP) by Elizabeth C. Matsui, MD, MHS, a professor of population health and pediatrics and director of the Center for Health and Environment Education and Research at the University of Texas at Austin Dell Medical School. 

“Even though climate change has been here and has been affecting health already for a while, it’s just really impossible to ignore right now,” she told attendees in a session focused on climate change impacts on allergies and asthma. “The challenge is connecting the dots between something that is much larger, or feels much larger, than the patient and the family that’s in front of you.” 

The reality, however, is that climate change is now impacting patients’ health on an individual level, and pediatricians have a responsibility to understand how that’s happening and to help their families prepare for it. 

“From the perspective of someone who went into medicine to practice and take care of the individual patient, I think it has been more difficult to connect those dots, and for the people in this room, it’s our job to connect those dots,” Matsui said. She also acknowledged that many of the solutions are frustratingly limited to the policy level and challenging to implement, “but it doesn’t mean that we can’t make a difference for the patients who are in front of us.” 

Charles Moon, MD, a pediatrician and Pediatric Environmental Health Fellow at the Children’s Environmental Health Center, Icahn School of Medicine at Mount Sinai, New York City, found the talk particularly helpful in providing information about both the broader issue and what it means on a local practice level. 

“The biggest takeaway is that more people and more pediatricians are tuning in to this issue and realizing the dangers,” Moon told Medscape Medical News. “It’s clear that a larger community is forming around this, and I think we are at the cusp where more and more people will be coming in. We are really focusing on taking all the data and trying to figure out solutions. I think the solutions orientation is the most important part.” 

Understanding the Big Picture

Matsui opened with a general discussion of the human causes of climate change and the effects on a global scale presently and in the future. For example, over the past 800,000 years, carbon dioxide levels have never been above 300 ppm, but they surpassed that threshold in 1911 and have reached 420 ppm today. The trapping of heat in Earth’s atmosphere caused by the increase in carbon dioxide and other greenhouse gases is leading to multiple phenomena that impact health, such as longer growing seasons; increased droughts, heat waves, and wildfire seasons; and higher temperatures. These changes, in turn, affect allergens and asthma.

Children are particularly vulnerable to climate change impacts because they have a higher risk for developing asthma, allergic disease, and infections, Matsui said. Childhood is a critical period for lung and immune development, and the Environmental Protection Agency’s 2023 Climate Change and Children’s Health and Well-Being report projects that an increase of 2 °C in global warming will result in an additional 34,500 pediatric asthma cases and 228,000 allergic rhinitis cases per year, driven largely by predicted increases in ozone and 2.5-µm particulate matter. The report also forecasts an increase in 6240 asthma emergency department visits and 332 additional respiratory hospitalizations per year. 

“We know that these associations that we see between climate change exposures and poor respiratory health outcomes in kids are biologically plausible,” Matsui said. “They’re not just correlation without causation. A lot of the mechanisms for how air pollution, allergies, and other factors directly affect the lungs of the airway epithelium have been worked out.” 

An Increase in Allergens and Viral Infections

Pediatricians should prepare for anticipated growth in allergens and viral infections. The longer growing seasons mean that pollen seasons will also lengthen. Meanwhile, higher concentrations of carbon dioxide cause individual plants to produce more pollen. 

“As the winters get warmer, mice that might not be able to survive during the winter are surviving, and mice reproduce at a very rapid rate,” she said. “The increase in moisture means that dust mites, which absorb their water — they drink by absorbing humidity that’s in the air — will be present in higher concentrations, and their range will expand.”

Fungal and mold exposures are also increasing, not just outdoors but also indoors, “and there are all sorts of allergic and respiratory health consequences of fungal exposure,” Matsui said. As hurricanes and flooding increase, storm damage can also make indoor environments more conducive to fungal and mold growth. 

Extreme weather from climate change also affects infrastructure. “When there’s healthcare infrastructure disruption and other infrastructure disruption, it adds to the challenge,” she said. “It compounds all the other threat to health from climate change, so this overall problem of climate change and health is multidimensional and very complicated.”

Then there’s the impact of climate change on respiratory viruses, which are a major driver of asthma exacerbations, Matsui said. The greater variability in daytime temperatures affects environmental reservoirs, transmission patterns, geographical ranges, and seasonality of various respiratory pathogens. The prevalence of respiratory syncytial virus infections, for example, increases during humid periods. 

“This is coupled with the fact that the projected increases in air pollution increase susceptibility to respiratory virus infections,” Matsui said. “In fact, climate change and air pollution are inextricably linked.” 

Climate Change and Air Pollution

Climate disruption creates extreme weather patterns that then lead to worsening air quality due to high temperatures; heavier precipitation; and more forest fires, droughts, dust storms, thunderstorms, hurricanes, stagnation events, and other extreme weather. Matsui shared a map showing the substantial increase in days with stagnant air since 1973. During stagnation events, air pollution builds up in the atmosphere because of a stable air mass that remains over a region for several days, with low-level winds and no precipitation. 

The pollutants can then contribute to rising temperatures. Black carbon particulate matter released from the burning of forests and other biomass absorbs more solar radiation, further contributing to temperature increases. Data from the National Bureau of Economic Research has shown that the US made big strides in reducing air pollution from 2009 through 2016, but it began to reverse in 2016 as severe weather events picked up. 

Pediatricians need to be cognizant of the synergistic effect of these different impacts as well. “We oftentimes talk about these problems in a silo, so we may talk about air pollution and health effects, or allergens and health effects, or heat and health effects, but all of these interact with each other and further compound the health effects,” compared to just one of them in isolation, Matsui said.

For example, air pollution increases sensitivity to allergen exposure and increases reaction severity, which disrupts the immune tolerance to allergens. “Heat and air pollution also interact, and the combination of the two is more deadly than either one alone,” she said. 

Air pollution from wildfire smoke is also more toxic to the lungs than air pollution from other sources, so if there’s wildfire-based air pollution, the impact on respiratory hospitalizations is significantly greater. Even in places that would not otherwise be at risk for wildfires, the threat remains of air pollution from more distant fires, as New York City experienced from Canadian wildfires last year. 

“This is a problem that is not just isolated to the parts of the world where the wildfires are located,” Matsui said.

Moon, who practices in New York City, said he really appreciated Matsui’s perspectives and nuanced advice as a subspecialist “because it’s obvious that the way we deliver healthcare is going to have to change based on climate change.” He hopes to see more subspecialists from other pediatric areas getting involved in looking at climate impacts and providing nuanced advice about changing clinical care similar to the examples Matsui provided. 

Air pollution can also be deadly, as a landmark case in the United Kingdom revealed a few years ago when the court ruled that a child’s death from an asthma attack was directly due to air pollution. In addition to causing worse asthma symptoms and exacerbations, air pollution also adds to the risk of developing asthma and impedes lung growth, all of which disproportionately affects disadvantaged and minoritized communities, she said. 

Greater Impact on Disadvantaged Populations

Matsui called attention to the equity implications of climate change impacts on health. 

“If you have a community that does not have the infrastructure and access to resources, and that same community has a prevalence of asthma that is double that of their more advantaged and white counterparts, then the impacts of climate change are going to be amplified even more,” she said.

For example, a 2019 study found that the biggest predictor of the location of ragweed plants has to do with vacant lots and demolition of housing. Ragweed plants being more common in neighborhoods with vacant lots will disproportionately affect disadvantaged neighborhoods, she said. Another study found in Baltimore that mouse allergens — specifically urine — were a bigger cause of asthma in low-income children than were cockroach allergens. 

“It’s important to consider context,” including age, gender and social and behavioral context, she said. “We as pediatricians know that children are particularly vulnerable, and what happens to them has an effect across the lifespan.” 

Furthermore, pediatricians are aware that disadvantaged and minoritized communities lack infrastructure; often live in areas with greater air pollution; often have heat islands in their communities without protection, such as tree canopy; and may be at greater flooding risk. “Poverty is also associated with increased vulnerability” because of poorer housing and infrastructure, less education, less access to care, more preexisting health conditions and greater discrimination, she said.

Three Cornerstone Interventions

Interventions fall into three main buckets, Matsui said: mitigation, adaption, and resilience. 

“Mitigation means reducing greenhouse gas and air pollution production and trying to enhance sinks for greenhouse gases,” she said. Mitigation strategies primarily occur at the policy level, with improved regulation, treaties, and market-based approaches, such as carbon tax and cap and trade. 

Adaptation includes actions that lessen the impact on health and environment, such as infrastructure changes and implementation of air conditioning. Examples of climate change adaptation strategies also mostly come from policy but largely at state and local levels, where individual pediatricians have a greater voice and influence. These can include changes in urban planning to address heat islands, flooding risk, and public transportation’s contribution to air pollution and climate change. It can also include changes in housing regulation and policy and investments in healthcare, such as expanded Medicaid and health insurance and investing in disaster planning and readiness. 

“Resilience is a more holistic concept,” Matsui said, “which advocates for system-wide, multilevel changes and involves a range of strategies to enhance social, human, natural, physical, and financial capacities.”

What Pediatricians Can Do

Pediatricians have an important role to play when it comes to climate change and health impacts. 

“The first step is sort of understanding the complexity of climate change in terms of its potential health effects, but also being prepared to talk with our patients and their families about it,” Matsui said. “The second step is advocacy.” 

She drew attention to the February policy statement in Pediatrics that discusses precisely the ways in which pediatricians can leverage their expertise and credibility. 

“Pediatricians are ideal advocates with whom to partner and uplift youth and community voices working to advance zero-carbon energy policy and climate justice,” she said. “There are many opportunities to advocate for climate solution policies at the local, state, national, and even international level.” 

These roles can include educating elected officials and health insurance entities about the risks that climate change poses to allergies, asthma, and child health more broadly, as well as the benefits of local solutions, including improved air quality, tree canopy, and green space. “There are lots of opportunities to engage with the community, including speaking at public hearings, serving as an expert testimony, and writing letters to the editor,” she said. 

The impact of these efforts can be further maximized by working with other healthcare professionals. Lori Byron, MD, a pediatrician from Red Lodge, Montana, who heads the AAP Chapter Climate Advocates program, noted during Q&A that every AAP chapter in the country has climate advocates. She added that the AAP is the first medical board to have climate modules in their maintenance of certification specifically designed to incorporate climate change education into well visits.

Adjusting Clinical Care

Meanwhile, in patient care, Matsui acknowledged it can be frustrating to think about what a massive impact climate has and simultaneously challenging to engage families in discussions about it. However, a wide range of resources are available that can be provided to patients. 

“For a patient in front of you, being informed and prepared to talk about it is the first step to being able to assess their climate change risk and provide tailored guidance,” she said. Tailored guidance takes into account the child’s specific health situation and the risks they’re most likely to encounter, such as wildfire smoke, air pollution, longer pollen seasons, environmental allergens, or disruption of infrastructure. 

“If I am seeing a patient with asthma who is allergic to a particular pollen, I can anticipate that that pollen may be present in higher levels of the future, and that the season for that pollen may be longer,” Matsui said. “So if I’m thinking about allergen immunotherapy for that patient, future risk may be something that would push the conversation and the shared decision-making” from possible consideration to more serious consideration, depending on the child’s age. 

“Another example is a patient with asthma, thinking about wildfire risk and having them prepared, because we know from data that wildfire air pollution is going to be worse for that child than pollution from other sources, and there are ways for them to be prepared,” Matsui said. For instance, having an HVAC system with a high-grade air filter (at least a MERV 13) will filter the air better if a wildfire causes smoke to descend over an area. Portable, less expensive HEPA filters are also an option if a family cannot upgrade their system, and wearing an N95 or N95-equivalent mask can also reduce the impact of high air pollution levels. 

An example of thinking about the impact of potential infrastructure disruption could be ensuring patients have enough of all their medications if they’re close to running out. “It’s important for them to always have think about their medications and get those refills ahead of a storm,” she said.

Additional Resources 

Understanding that pediatricians may not have time to discuss all these issues or have broader conversations about climate change during visits, Matsui highlighted the AAP website of resources on climate change. In addition to resources for pediatricians, such as a basic fact sheet about climate change impacts on children’s health and the technical report that informed the policy statement, the site has multiple resources for families: 

The following resources can also be helpful to pediatricians and/or families:

In some states, Medicaid will provide or cover the cost of air conditioning and/or air filters.

The presentation did not involve external funding. Matsui and Moon had no disclosures. 

Tara Haelle is a Dallas-based science journalist.