Prof Yuming Guo

The impact of climate change, including heatwaves, poorer air quality, flooding events and more intense cyclones are affecting respiratory health, hospitalisations and mortality, according to data from a global leader in environmental epidemiology.

Professor Yuming Guo, Head of the Monash Climate, Air Quality Research (CARE) Unit, presented numerous examples from large datasets including from Australia, Brazil and China that climate change is already making its impact felt at patient and population levels.

For example,

• Life-time summer heat exposure is significantly associated with the reduction of lung function in young Chinese adults. Those with respiratory diseases and without exposure to fans and air conditioning for cooling were particularly vulnerable. [link here]
• Temperature variability was associated with asthma hospitalisations for all age groups but particular the elderly in a study of almost 3 million hospitalisations in Brazil. [link here]
• Modelling scenarios across 47 countries identified that the frequency of heat-related mortality events has been increasing for 20 years and will continue to worsen. [link here]
• Short term exposure to fine particular matter (PM_2.5) such as from bushfire smoke is associated with 1 million premature deaths globally. [link here]
• A study across 372 cities worldwide shows PM_2.5 and ozone have a synergistic impact on total, cardiovascular and respiratory mortality. [link here]
• A study across 35 countries shows that floods increase all cause, cardiovascular, and respiratory mortality for up to 60 days after exposure. [link here]
• Mortality data from 18 countries or territories shows tropical cyclone exposure is associated with a prolonged elevated risk of all-cause, cardiovascular, and respiratory mortality, with an average period of concern of about 20 days. [link here]

Professor Guo also said that green space mitigates the effects of temperature and air pollution on mortality.

Airborne threats

Professor Guy Marks

Speaking in the same session, Scientia Professor Guy Marks from the University of NSW, told the meeting not to take safe air for granted.

He said airborne threats included the aeroallergens contributing to thunderstorm asthma, bushfire smoke, workplace exposures, outdoor and indoor air pollution, and infectious agents.

Regarding options for control of airborne exposures, he said the most effective approach was to control the source by, for example, controlling the burning of biomass and fossil fuels or reducing emission from vehicles and industrial processes.

The next effective approach was to improve air quality such as by using filters to remove airborne threats in homes, workplaces, schools and other facilities.

“We can’t really control the receiver [the person who is at risk] apart from strategies such as mask use.”

Professor Adrian Lowe, Co-Head of the University of Melbourne’s Allergy and Lung Health Unit, told the meeting that climate change would impact exposures to aeroallergens such as grass pollens and fungi which were implicated in asthma.

He said it had already been modelled that increasing temperatures would expand the distribution of ragweed and extend the summer-autumn season for pollen exposure in Europe – effectively doubling the number of people being sensitized.

Meanwhile, flooding events were likely to increase exposure to moulds.

What respiratory physicians can do

Em Prof Michael Abramson

Emeritus Professor Michael Abramson, from the School of Public Health & Preventive Medicine at Monash University, told the meeting that the profession could respond to the threat of climate change through their organisations, as clinicians and as concerned citizens.

He said TSANZ had already joined other professional societies in declaring climate change a medical emergency, in making parliamentary submissions such as to the Climate Change Amendment (Duty of Care and Intergenerational Climate Equity) Bill 2023, and through relevant position statements regarding issues such as the environmental impact of inhaled medications.

As clinicians, an approach was to ensure the optimal management of patients with asthma. The UK-led CARBON study, published recently in Thorax [link here], found 47.3% of the 236,506 patients were categorised as having poorly controlled asthma.

The result of suboptimal asthma control was excess greenhouse emissions associated with more SABA inhaler use, more frequent exacerbations and routine health care resource use compared to people with well controlled asthma.

“These findings indicate that efforts to improve asthma treatment practices to curtail high SABA use as part of an overall management strategy that seeks to implement evidence-based treatment recommendations and address other contributing factors to poor asthma control, such as suboptimal adherence to medication and poor inhaler technique, could result in substantial carbon savings,” the study said.

Professor Abramson said as concerned citizens, strategies to reduce individual carbon footprints included:

• choosing ethical superannuations funds
• not investing in cryptocurrencies
• home modifications such as getting off gas and installing solar
• choosing active or public transport
• driving an electric car.