The “baby-on-board”-style card, which can be downloaded from the TfL website or shown on a mobile phone, was launched following concerns from asthma sufferers who were facing scrutiny from fellow passengers for not wearing a mask.
Since 15 June, face coverings have been mandatory on public transport in England following changes to government guidelines.
The new rules mean that anyone travelling by train, Tube, bus, ferry or plane in England should be wearing a face covering, and those travelling by train will be asked to cover their face as they enter a station.
However, some groups are exempt from the rule, including children under the age of 11, people with disabilities or breathing problems and anyone travelling with someone who lip-reads.
Anyone who is unable to use a face covering because of a physical or mental illness, as defined by the 2010 Equality Act, is also exempt, as well as TfL staff, on-duty police officers and emergency services employees.
Shona Muraldo-Parks, an asthma sufferer from London, told the Evening Standard that she wore a home-made “I have asthma” badge after being criticised by fellow passengers for not wearing a face covering after they became mandatory from June 15.
Noting that her condition would be exacerbated by wearing a face covering, Muraldo-Parks called on TfL to design cards that are similar to its “Baby-on-Board” and “please offer me a seat” badges.
She said: “There was a couple on the bus and, as I walked past, I heard the man say to the woman: ‘See how people don’t have any respect.’
“Then on Tuesday I went to my mum’s and the bus driver signalled for me to put on a mask. I just said I have got asthma and he let me on. On the bus, everyone is very worried about everyone else and I did notice people looking at me.”
Jessica Kirby, Head of Health Advice at Asthma UK, said: “For some people with asthma, wearing a face covering might not be easy. It could make it feel harder to breathe.
"The UK government has advised that people with respiratory conditions don’t need to wear face coverings, so if you are finding it hard, then don’t wear one. If you’re comfortable to wear a face covering, please use a cloth or home-made one, not a medical type face mask.”
TfL is temporarily handing out free face coverings at a number of Tube and bus stations.
Staynton Brown, Director of Diversity, Inclusion and Talent for TfL, said: “TfL staff and policing partners have been fully briefed on the exemptions, and to support customers and to make it easier for staff and the police to know who should and shouldn’t wear a face covering, we have introduced a new exemption card that customers will be able to download and carry with them or display on their mobile phone.
“This will provide reassurance to a number of different groups, including those with some conditions, who might have difficulties wearing face coverings.
“We’d like to remind customers to treat everyone on the transport network with respect and compassion, and to understand that some customers and staff will be unable to wear a face covering for medical reasons that may not be immediately obvious.”
The latest guidelines extend to hospitals, where all visitors and outpatients in England are advised to wear face coverings, unless exempt. Health staff will now wear surgical masks at all times.
Uber has also made face coverings mandatory for customers and drivers, while taking additional safety measures such as regularly sanitising their cars. Customers will also be reminded to sit in the backseat only and to roll down the windows for ventilation.