Domestic airports have enhanced security measures after a disabled man set off a bomb on Saturday at Beijing Capital International Airport.
Explosives checks are being carried out at the entrances of the arrival and departure halls at the airport, with security personnel swiping palm-sized testing paper on passengers' luggage.
SWAT officers have been deployed in the halls, Beijing police announced on Sunday, and police dogs have also been deployed.
The anti-explosive measures came after an incident on Saturday evening when Ji Zhongxing, 34, set off a homemade bomb at the Beijing airport, injuring himself and a security guard.
Ji, from Heze, Shandong province, claimed in his blog that he had been attacked and paralysed by police in Dongguan, Guangdong province, in 2005, and his lawsuit against the police failed in 2006.
The explosion occurred outside Gate B of the Terminal 3 arrival hall, where people don't need security checks.
Beijing police said on Sunday that Ji had been taken into custody and they were investigating how he got the explosives, what his motives were and whether there were any other suspects.
Airports in many other cities, including Shanghai and Shenzhen, have also upgraded security measures.
Shanghai's Pudong and Hongqiao international airports have been checking for explosives at exits and entrances since Sunday, according to the Shanghai Airport Authority, which operates the airports.
"It's a spot check not only for the departure floor, but also the arrival floor - you'd be checked even if you're in the airport to pick up friends," said a staff member of the Pudong International Airport's inspection centre who declined to give his name.
Shi Daoxiong, spokesman for Shenzhen Airport (Group) Co, operator of Shenzhen Baoan International Airport, said the inspection only takes a few seconds.
"The inspection is a regular part of instructions from the Civil Aviation Administration of China. We used to run the check three days every month," he said.
Shi still advises passengers to arrive at the airport about half an hour earlier.
Starting on Monday, passengers at Sanya Phoenix International Airport in Hainan province have to go through extra security checks at the entrances of domestic and international terminals, the airport said on Monday morning.
Some entrances will be closed temporarily, and all others will be for one-way traffic, the Sanya airport said.
The Civil Aviation Administration of China required beefing up security measures, the airport said, reminding passengers to arrive ahead of time.
The Civil Aviation Administration of China was unavailable for comment on Monday.
Sun Ying, traveling from Beijing to Shanghai, said the enhanced security measures made her feel safe.
"The testing paper is efficient, and it doesn't take much time," she said. "Safety should always be the top priority."