In South Indian states such as Tamil Nadu, Karnataka, and Kerala, urban and peri-urban areas report a relatively high prevalence of asthma and COPD.
Published Oct 31, 2025 | 1:11 PM ⚊ Updated Oct 31, 2025 | 1:11 PM
A man using an inhaler. (iStock)
Synopsis: A recent US study found that metered-dose inhalers are responsible for almost all inhaler-related emissions. This opens a window to India, particularly South Indian states such as Tamil Nadu, Karnataka and Kerala, where asthma is highly prevalent.
A recent US study published in JAMA found that metered-dose inhalers (pMDIs) are responsible for almost all inhaler-related emissions. The study, Inhaler-Related Greenhouse Gas Emissions in the US: A Serial Cross-Sectional Analysis, observed greenhouse gas emissions from inhalers used for asthma and chronic obstructive pulmonary disease (COPD).
A metered-dose inhaler (MDI) is a small, handheld device that delivers a set amount of medicine as a mist for you to breathe directly into your lungs. It has a pressurised canister fitted into a plastic holder with a mouthpiece and, when pressed, it releases the medication in a fine spray, helping people with asthma or other breathing problems get quick relief.
The study estimated that from 2014 to 2024, pMDIs produced about 24.9 million metric tons of carbon dioxide equivalent. In addition, the social cost of these emissions, the economic impact on society, was calculated at $5.7 billion.
While the findings are US-based, they are highly relevant for India, particularly in South Indian states such as Tamil Nadu, Karnataka, and Kerala, where urban and peri-urban areas report a relatively high prevalence of asthma and COPD.
With chronic respiratory disease burdens rising and environmental concerns gaining attention, the study opens a discussion on reducing inhaler emissions while maintaining patient care.
The JAMA study highlighted that inhaler emissions are heavily concentrated among a few high-use medications, such as albuterol, budesonide-formoterol, and fluticasone propionate.
By strategically targeting prescribing practices, for example, favouring propellant-free devices where clinically appropriate, healthcare providers could substantially reduce the carbon footprint of respiratory therapy.
Importantly, the study emphasises that these changes can be made without compromising patient care, making it a feasible and practical approach for clinicians aiming to balance environmental responsibility with effective disease management.
Beyond clinical practice, the study frames inhaler emissions as a policy-relevant issue. It suggests that regulators, healthcare systems, and procurement agencies could play a key role by promoting lower-emission inhaler options, setting guidelines for sustainable prescribing, and incentivising the adoption of propellant-free devices.
These systemic measures could not only reduce environmental impact but also raise awareness among prescribers and patients, embedding sustainability into routine respiratory care.
While the study is based on US data, the underlying mechanism is globally relevant. Hydrofluorocarbon (HFC) propellants in pMDIs contribute heavily to greenhouse gas emissions, and regions with a high burden of respiratory disease could see meaningful benefits by examining inhaler practices.
This opens a window to India, particularly South Indian states such as Tamil Nadu, Karnataka and Kerala, where asthma is highly prevalent and often coexists with allergic rhinitis, a trend highlighted by the Coexistence of Allergic Rhinitis and Asthma (CARAS) survey, which found the highest prevalence of coexisting conditions (80%) in southern regions of India (Jaggi et al., Lung India, 2019).
Dr Sameer Bansal, Senior Consultant Pulmonologist at Vaayu Chest and Sleep Specialists in Bengaluru, told South First, “HFC propellants in pressurised metered-dose inhalers have a very high global-warming potential.”
He noted that South India has a substantial burden of asthma and COPD in urban centres like Chennai, Bengaluru and peri-urban/rural belts, with risk amplified by biomass exposure, air pollution, and ageing. “That makes any avoidable emissions from chronic therapies worth examining, even if clinical control remains the top priority,” he added.
When it comes to prescribing, there are simple opportunities to reduce environmental impact. Dr Bansal explained, “Where a patient can use a dry powder inhaler effectively, this can lower emissions without affecting their treatment.”
Device technique matters too: pMDIs require coordination between pressing and inhaling, and studies in India show higher error rates with these devices. Structured training, combined with using breath-actuated DPIs or soft mist inhalers where suitable, can improve both patient outcomes and reduce carbon impact.
Policy and healthcare systems also have a role to play. India’s commitment to an HFC phase-down under the Kigali Amendment and its national strategy finalised in 2023 can push manufacturers and hospitals toward low-emission alternatives.
Dr Bansal suggested practical steps: Encourage procurement of low-GWP inhalers, provide CO₂e information per device, and set up pharmacy take-back programs for spent pMDIs to avoid releasing leftover propellant.
Patient awareness rounds out the approach. “Start with control, not carbon,” Dr Bansal advised. Patients need to understand that symptom management comes first, but where equally effective, lower-emission devices can be considered.
Demonstrating proper technique, using teach-back methods, and discussing safe disposal are simple but effective ways to engage patients. Neutral tools showing the carbon footprint can help patients participate in decision-making without feeling pressured.
Dr Bansal emphasised a practical, stepwise approach: First, ensure the right drug, dose, and technique; second, optimise device choice with DPIs, SMIs, or low-GWP pMDIs; and third, implement system-level measures like CO₂e-informed procurement, technique coaching, and canister take-back programmes.
“Communities that face the highest burden of respiratory disease also face climate vulnerability,” he said, and added, “A patient-first approach to decarbonising inhaler use protects both health and the environment.”
(Edited by Muhammed Fazil.)
