Gao Yuhan, 51, is the "ambulance" in his west Beijing community.
He and other volunteers carry elderly people down stairways when they are too unwell to walk down themselves.
On receiving a call for help, Gao hurries to the patient's house with a stretcher and informs other stretcher bearers. Carrying a patient to the ground floor usually takes about five minutes. Sometimes he responds faster than an ambulance.
China's emergency medical response teams usually comprise a doctor and a nurse. Without help, two medical staff can struggle to get a patient to an ambulance.
Though not big, Gao says he is strong enough, steady enough and fast enough for the task. Since 2008, his stretcher team has grown from six to 21 members, including cleaners, security guards and volunteer residents. They have helped many people get timely treatment.
"He's like a member of my family," says neighbor Liu Yunmao, 63. Gao, the Communist Party secretary of Jian'gangnanli community, carried her to hospital after she broke her leg in 2013.
China had more than 230 million people aged 60 or over at the end of 2016, or 16.7 percent of the total population. This group is expected to be a quarter of the population by 2030.
However, most residential buildings in Gao's community were built in 1960s and are six stories high, but without elevators. Elderly people living on the fifth floor or above find going downstairs difficult.
Jian'gangnanli has almost 5,000 residents, most of them retired. Gao says 40 percent of residents are over 60. A third do not live with their children and "they don't want to go to a nursing home."
First aid resources are tight. Beijing emergency center dispatches ambulances about 900 to 1,000 times a day on average, but there were fewer than 50 stretcher bearers in 2016. Professional stretcher bearers are dispatched only for very urgent cases.
If a doctor and a nurse cannot carry a patient to the ambulance, they usually ask neighbors to help, but it can delay treatment.
Instead of an ambulance, some residents call the stretcher team. In Beijing, an ambulance callout usually costs 180 yuan, but Gao's service is always free.
Gao will never forget the day his father called him to say his mother had suffered a stroke at home. He immediately left work, but it still took two and a half hours to get there. When he arrived, his mother had died.
"I could not sleep for a long time," he recalls.
A few months later, he took a job on the residents' committee and eventually took charge of the stretcher team. Gao has helped carry more than 80 elderly people more than 280 times in the past nine years.
"It has helped me come to terms with my mom's death," he says.
Gao recalls a woman asking him to help carry her husband, a 200-kilogram man, who was almost 80 years old and in a critical condition.
Gao called seven teammates to help. They took 15 minutes to carry the man from the sixth floor to the ambulance. It was winter, but they were drenched with sweat and their legs trembled under the weight. The patient survived.
Gao has also helped carry the dead. But not all volunteers do that job, as many Chinese believe that touching a corpse will bring misfortune.
Gao was scared too, but he still lent a hand and refused payment from the families.
He has injured his hands and arms on handrails several times while carrying stretchers in narrow corridors. He also suffers lumbar strain.
Some people give him money to buy himself food and medicines, but Gao spends it on new stretchers, uniforms and emergency training.
Last year, Beijing set a goal of installing elevators in older buildings. In March, the municipal government issued regulations on emergency treatment, requiring the duty of carrying patients to an ambulance. The 120 Emergency Center hired hundreds of stretcher bearers this year and accelerated training of staff.
Liu Hongmei, deputy director of Beijing Emergency Center, says big cities lack stretcher bearers, emergency personnel and ambulances. High workloads and low pay also discourage people.
She suggests the private sector could help fill the gap for non-emergency patients.
Gao wants more young volunteers as the average age of stretcher bearers is 50.
"Everyone gets old. I hope I can inspire people to join and take care of the elderly."