Switching to ‘green’ inhalers could reduce carbon footprint by 37-fold

Asthma sufferers who switch to ‘green’ inhalers would have the same effect on the environment as cutting out meat, scientists say. 

The NHS has been urged to replace metered-dose inhalers, after researchers found they had a carbon footprint 37 times that of dry powdered ones. 

Metered dose inhalers accounted for 70 per cent of the 50million inhalers that were prescribed in the UK in 2017. 

Replacing one in ten of them for a dry powder alternative could reduce annual CO2 emissions by 58,000 tonnes, Cambridge University experts found.

This is the same amount of pollution that would be emitted during 180,000 return car journeys from London to Edinburgh. 

Metered dose inhalers contain substances known as hydrofluorocarbons to help propel the drug into the respiratory system.

Asthma patients are being encouraged to use more environmentally-friendly inhalers (file image)

They have an estimated carbon footprint of 18oz (500g) of carbon dioxide equivalent per dose.

Five doses from a metered dose inhaler can have the same carbon emissions as a nine-mile (14km) trip in a car.

They contain around 100 doses, meaning they have emitted the same amount of carbon as a 180mile (290km) car trip by the time they are empty. 

At the individual level each of these inhalers replaced by a dry powder inhaler could save the equivalent of between 5291oz (150kg) and 14110oz (400kg) of CO2 annually, the scientists say.  

The team, led by Dr Alexander Wilkinson, claim this could have the same effect on the environment as recycling or cutting out meat. 

But people should not cut back on their medication to try to reduce emissions, the researchers warned.

Instead, patients should discuss whether environmentally friendly inhalers are available and appropriate for them to use, they said. 

The carbon footprint of the devices accounts for almost four per cent of the NHS’ entire greenhouse gas emissions.

There have been calls to move to more environmentally sustainable alternatives for several years.


Many asthmatics currently use metered dose inhalers, which contain substances known as hydrofluorocarbons to help propel the dose into their respiratory system.

These devices have an estimated carbon footprint of 500g of carbon dioxide equivalent per dose.

Five doses from a metered dose inhaler can have the same carbon emissions as a nine-mile trip in a car, Nice said.

By comparison, dry powder inhalers contain just 20g of carbon dioxide per equivalent dose and work well for many patients.

But health authorities have repeatedly baulked at the price of greener, dry powder inhalers.

But, in their study published in BMJ Open, the researchers argue the NHS could actually cut costs by making their prescription inhalers more environmentally-friendly.

They say replacing one in 10 metred dose inhalers with the least expensive brands of dry powder equivalents could reduce drug costs by £8.2million annually.

Dr Wilkinson, consultant in respiratory medicine from East and North Hertfordshire Trust, said: ‘Any move towards “greener” inhalers would need to ensure that replacements were cost effective.

‘By switching to less expensive brands, we’ve shown it would still be possible to make a positive impact on carbon emissions while at the same time reducing drug costs.

‘It’s important to stress that patients shouldn’t stop using their usual treatments to reduce their carbon footprint.’  

People can also make sure they are using their inhalers correctly, return finished ones to pharmacies for proper disposal and avoid throwing away half-full items to help reduce the carbon footprint of their medication, he said.

Study co-author Dr James Smith, consultant in public health at Cambridge University, added: ‘Climate change is a huge and present threat to health that will disproportionately impact the poorest and most vulnerable on the planet, including people with pre-existing lung disease.

‘Our study shows switching to inhalers which are better for the environment could help individuals, and the NHS as a whole, reduce their impact on the climate significantly.

‘This is an important step towards creating a zero carbon healthcare system fit for the 21st Century.’ 

Jessica Kirby, head of health advice at Asthma UK, said: ‘We recognise the need to protect the environment, but it’s critically important that people with asthma receive the medicines they need to stay well and avoid a life-threatening asthma attack.

‘Switching to a different type of inhaler can be complicated for people with asthma, as it involves learning a new inhaler technique, so it should only be done with support from a GP or asthma nurse.

‘Taking inhalers properly is essential to get the medicine you need and reduce the chance of side effects.

‘It is vital that you keep using your inhalers as prescribed. If you are concerned about the environmental effects, talk to your doctor or asthma nurse at your next annual asthma review, to see whether there is another type of inhaler that would work for you.’ 


According to the Environmental protection Agency, there are six major pollutants which can impact on human health and well-being. 

Particulate matter: Particulate matter is the term for a mixture of solid particles and liquid droplets found in the air.

These particles come in many sizes and shapes and can be made up of hundreds of different chemicals.

Some are emitted directly from a source, such as construction sites, unpaved roads, fields, smokestacks or fires.

Fine particles (2.5 parts per million)are the main cause of reduced visibility (haze) in parts of the United States, including many of our treasured national parks and wilderness areas. 

Carbon monoxide: Breathing air with a high concentration of CO reduces the amount of oxygen that can be transported in the blood stream to critical organs like the heart and brain.

At very high levels, which are possible indoors or in other enclosed environments, CO can cause dizziness, confusion, unconsciousness and death.  

Nitrogen dioxide: Nitrogen dioxide primarily gets in the air from the burning of fuel. NO

It forms from emissions from cars, trucks and buses, power plants, and off-road equipment.

Breathing air with a high concentration of NO can irritate airways in the human respiratory system. Such exposures over short periods can aggravate respiratory diseases, particularly asthma, leading to respiratory symptoms (such as coughing, wheezing or difficulty breathing).   

Sulfur dioxide: The largest source of Sulfur dioxide in the atmosphere is the burning of fossil fuels by power plants and other industrial facilities.

Short-term exposures to SO can harm the human respiratory system and make breathing difficult. Children, the elderly, and those who suffer from asthma are particularly sensitive to effects of SO.

Ground-level Ozone: The ozone layer in the lower area of the lower portion of the stratosphere, approximately 12 to 19 miles above the surface of the planet (20 to 30 km). 

Although ozone protects us against UV radiation, when it is found at ground level it can cause health problems for vulnerable people who suffer from lung diseases such as asthma. 

It is created by chemical reactions between oxides of nitrogen (NOx) and volatile organic compounds (VOC) – that are found in exhaust fumes – in the presence of sunlight.

Lead: Major sources of lead in the air are ore and metals processing and piston-engine aircraft operating on leaded aviation fuel. 

Other sources are waste incinerators, utilities, and lead-acid battery manufacturers. The highest air concentrations of lead are usually found near lead smelters.

 Depending on the level of exposure, lead can adversely affect the nervous system, kidney function, immune system, reproductive and developmental systems and the cardiovascular system.

Infants and young children are especially sensitive to even low levels of lead, which may contribute to behavioural problems, learning deficits and lowered IQ.

Source: EPA 

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