In 1981, the first Beijing International Marathon attracted a meager 188 participants, most of them Chinese full-time athletes.

Schedule of Chinese marathons and road races in 2014

Thirty-two years later, the 2013 event boasted a field of 30,000, including about 1,000 foreigners, and all the race slots were filled just 13 hours after registration opened. This time, a mere 1 percent of the runners were professionals.

The transformation from an elite sport into a mass participation activity helped the Beijing Marathon generate a profit of 30 million yuan ($4.8 million) in 2013, easily making it the country's most profitable marathon. Meanwhile, statistics from Adidas show that in 2013, sales of the company's sportswear in China increased by 16.1 percent compared with the previous year, a boost attributed in part to the manufacturer's sponsorship of the event.

Duan Shijie, chairman of the Chinese Athletic Association, said the National Fitness Program, launched in 1995, has played a huge role in promoting marathon fever and running as a whole. And despite the growing number of races and runners, Duan sees room for more.

According to figures collated by Duan, the United States, the world's largest economy, hosted 780 marathons in 2012. In Japan - the third-largest economy, but with a population just 10 percent of China's - the same year saw more than 200 marathons, and if one includes half-marathons, the figure soars tenfold. Meanwhile, Germany, France, the United Kingdom, Italy, Spain and Russia each held more than 100 marathons in 2012.

However, none of those countries has had to contend with the persistent air pollution that has plagued China in recent years and generated headlines around the world. In March, the organizing committee of the Shanghai International Marathon announced that it had moved the date of the 2014 race ahead to Nov 2 after warnings of high levels of air pollution in December, the month in which the event was originally scheduled. The move was heralded as evidence that marathon management in China had moved to a new level.

Naked pig run

The poor atmospheric conditions haven't dampened the enthusiasm of Chinese runners, despite repeated warnings from doctors about the risks associated with the inhalation of harmful particulates.

In the face of the deteriorating environment, hundreds of runners gathered in heavy smog at the Olympic Forest Park on Feb 23 for the city's third "Naked Pig Run," in which participants clad only in their underwear braved the polluted air and temperatures of around 1 C to undertake a 10-km run. Many wore face masks - some even wore military gas marks - to raise public awareness of environmental protection.

"The idea of the marathon is constantly enriched and developed by the spirit of equality and inclusivity it embodies. This public spirit is promoting a green and healthy lifestyle, and has become an active, socially positive force to help people realize that a clean environment is precious and to encourage them to adopt a low-carbon lifestyle," Ren said.

Contact the writer at zhanglei@chinadaily.com.cn