Climate change, air pollution, and allergic respiratory diseases: a call to action for health professionals

Did you know that over 272 million people worldwide live with asthma—and climate change is exacerbating their risk of severe attacks? A 2020 review published in the Chinese Medical Journal by researchers from Sun Yat-sen University, the University of New South Wales, and other global institutions reveals how rising temperatures, extreme weather, and worsening air pollution are creating a “perfect storm” for allergic respiratory diseases like asthma, rhinitis, and hay fever. The findings are a urgent reminder: climate change isn’t just an environmental issue—it’s a public health crisis.

How Climate Change Hits the Lungs

The Intergovernmental Panel on Climate Change (IPCC) confirms global temperatures have risen 1.1°C since pre-industrial times, with more heat waves, storms, and wildfires ahead. These shifts directly and indirectly harm respiratory health through two key pathways: temperature extremes and extreme weather events.

Temperature Extremes: Heat, Cold, and the Airway

Both scorching heat and frigid cold trigger asthma symptoms. For people with asthma, breathing hot, humid air can spike airway resistance by 112%—more than triple the effect of room-temperature air, according to a Kentucky study. In Hong Kong, daily mean temperatures over 27°C increased asthma hospitalizations, while Brisbane’s heat waves led to acute emergency visits for children with asthma.

Cold air is just as dangerous: it constricts tracheal muscles and reduces lung blood flow. A Canadian study found female athletes who exercised in cold air had higher rates of bronchoconstriction (a hallmark of asthma). In Shanghai, cold spells raised pediatric asthma outpatient visits, and Finnish research linked cold weather to worse symptoms in people with asthma or allergic rhinitis.

Even temperature swings matter: a 1°C rise in daily temperature range increased emergency asthma hospitalizations by 2.5% in Hong Kong. And air conditioning—used to cope with heat—can backfire: sudden cold blasts trigger bronchoconstriction, while closed windows trap pollutants like dust and mold.

Extreme Weather: Storms, Fires, and Dust

Climate change is making extreme weather more frequent—and more deadly for respiratory allergy sufferers:

Thunderstorm asthma: When storms hit during pollen season, they rupture pollen grains into tiny, inhalable particles. The 2016 Melbourne thunderstorm asthma event was catastrophic: 10 deaths, 9,000 hospitalizations, and 3,365 excess emergency visits in 30 hours. Risk factors included pre-existing asthma, pollen sensitivity, and being outdoors during the storm.
Floods: Wet conditions after floods boost mold growth. A New Orleans study found elevated mold spores post-Hurricane Katrina, and a meta-analysis linked home dampness/mold to a 30–50% higher risk of respiratory disease.
Wildfires: Smoke from wildfires (worsened by drought and heat) contains fine particulate matter (PM2.5) and ozone—both linked to asthma attacks. A North Carolina peat bog fire increased asthma emergency visits by 65%, while California wildfires raised asthma and COPD hospitalizations.
Dust storms: Drought and desertification fuel dust storms, which carry allergens like pollen, mold, and dust mites. In Kuwait, children 0–14 were the only group with a significant asthma risk from dust storms.

Air Pollution: A Double Whammy for Allergies

Climate change and air pollution are locked in a vicious cycle. Rising temperatures increase ozone formation (a lung irritant), while air stagnation traps pollutants like PM2.5. Wildfires and increased energy use for heating/cooling add more toxins to the air.

For people with allergies, this is deadly:

Ozone: High levels worsen lung function and increase airway inflammation. A California study found ozone exposure raised emergency asthma visits.
Traffic pollution: Diesel exhaust and PM2.5 attach to pollen, making it more allergenic. Korean research linked living near busy roads to higher asthma rates in children.
Synergy with heat: Extreme heat and pollution work together to worsen symptoms. A study of COPD patients found heat plus air pollution increased breathlessness more than either factor alone.

Aeroallergens: More Pollen, More Problems

Climate change is supercharging pollen seasons. Rising CO2 levels make plants produce more pollen—doubling CO2 increased ragweed pollen by 30–90% in experiments. Warmer temperatures lengthen pollen seasons: North American pollen seasons are now longer due to earlier springs and later frosts.

Pollution makes pollen even more dangerous. Ozone and PM2.5 alter pollen’s allergenic profile: birch pollen exposed to high ozone was more likely to trigger allergies in susceptible people. Traffic pollution increased ragweed pollen’s allergenicity compared to rural areas.

Who’s Most at Risk?

Two groups bear the brunt of climate change’s respiratory toll:

Urban residents: Cities have “heat islands” (warmer than surrounding areas) and higher pollution. A Spanish study found urban pollen seasons were twice as long as rural ones. Urban dwellers also face multiple stressors—traffic, mold, heat—that compound risk.
Children: Their lungs and immune systems are still developing. Prenatal exposure to pollution or heat increases preterm birth (a risk factor for asthma), while early-life allergen exposure impairs lung function long-term. A New Zealand study found exotic plants (linked to climate-driven migration) increased childhood asthma risk.

A Call to Action for Health Professionals

The study’s authors warn: climate change will cause “unexpected and persistent effects” on respiratory health—unless we act. Here’s what health professionals can do:

Advocate for mitigation: Push policymakers to cut greenhouse gas emissions (45% by 2030, net-zero by 2050) to limit warming to 1.5°C (per IPCC guidelines).
Champion adaptation: Support early warning systems for thunderstorms, wildfires, and heat waves. Use the “Allergy Safe Tree Decalogue”—planting non-allergenic trees, pruning before pollen season—to reduce airborne allergens.
Protect vulnerable groups: Screen patients for climate-related risks (e.g., outdoor work during heat waves) and tailor treatments. Educate families on reducing home mold (e.g., fixing leaks) and avoiding outdoor pollen during storms.

The Bottom Line

Climate change isn’t a distant threat—it’s here, and it’s making asthma and allergies worse. The Chinese Medical Journal study is a wake-up call: health professionals must lead the charge to protect patients from a warming planet. As the authors write, “We have an urgent need to transform our societies”—and that transformation starts with advocacy, adaptation, and action.

To read the full study, visit doi.org/10.1097/CM9.0000000000000861.

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