If not for the heavy smog that blanketed the capital city, the 34th Beijing Marathon on Sunday would have been almost flawless.

It is my favorite race not only because it ranks No 1 in China in terms of its history, size and levels of participants, but also because I recorded my personal best during last year's event. It is my home turf, and I wanted to take advantage of it again to test my limits.

I learned about the possibility of smog days ago, but still prayed on Saturday that a magical north wind would sweep the haze away overnight, as happened on Oct 20, 2013, when Beijing was blessed with an azure sky on race day despite heavy air pollution the previous days. But good luck did not befall us this time. When I looked out of my window early in the morning, I could barely make out the surrounding buildings.

A message sent by the organizing committee to my mobile said that to counter the hazardous air quality, it had added more medical staff and ambulances equipped with oxygen machines along the course and at the finishing area. It also asked the elderly and those with respiratory problems to think twice before deciding to hit the road. It was impossible to change the race date because nearly half of the runners were from outside Beijing, it added.

For me there was no flinching nor thought of giving in. Soldiers don't choose battlefields, and marathoners never choose conditions. It was with a little sense of self-heroism that I followed crowds through several underpasses and security checks before arriving at Tian'anmen Square at 7 am for the runners' carnival.

The hustle and bustle was like deja vu, as people greeted each other, took pictures and warmed up to tunes with strong rhythm. The only difference was that besides jackets, T-shirts, shorts, leggings and shoes of all brands and colors, some runners equipped themselves with a new accessory - a face mask.

Gone were long lines in front of public toilets. Last year, pictures of many runners answering nature's call at the square and along the walls of the Forbidden City took the media spotlight. To prevent such embarrassing scenes from recurring, organizers installed 500 toilets, more than 50 percent more than last year, in the square, making one toilet available for every 33 people, the highest ratio at any Chinese race. It took me less than five minutes to wait for a toilet to become available. At 8 am, I dashed out with the 30,000-strong crowd.

The following hours were party time, to eat, drink and enjoy. The supply of water, Gatorade and bananas was ample. From time to time, I exchanged high-fives with spectators who lined the streets rooting for us. The smog was gone from my mind. It was a day of glory for every runner.

As I crossed the finish line at the Bird's Nest after four hours and 37 minutes, I heard someone say jokingly: "Can't you see the smog has become thinner. It was all because of us human air purifiers?"

I laughed, and felt our efforts were all worthwhile, although I was 10 minutes short of my best time.

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