He started by searching high and low in Guiyang.
The worst of the last month's pollution stretched 1,100 miles south, closing highways near the south-western city Guiyang.
He despairs of the local police in Guiyang, who have not nabbed the kidnapping kingpins.
They opened a stall in the Red Side vegetable market, rented a single room with one stone bed and a stove, and raised a son, whom they nicknamed Xiao Guiyang, "Little Guiyang", in honour of the town that had given them a break.Two years ago Mr Wang was caught outside the market sprinkling water over his vegetables to make them look fresher.
As he fingered the only photographs he has of his son, dressed on his third birthday as a soldier of the People's Liberation Army, the unhappy father quietly recounted what he was doing to try to find Xiao Guiyang.
One father in Guiyang considers himself now to be a relative of the family that bought his son, and has changed the name of the boy, now back with him, to include the adoptive family's name.
He was almost certainly kidnapped by a criminal gang, one of several that prey on the children of migrant workers in Guiyang.
Mr Wang went off to the police station to pay his fine, leaving five-year-old Xiao Guiyang to play in the street.
Guiyang is nothing to shout about.
It now has large plants in Henan and Sichuan provinces, and is building a facility in Guiyang, one of China's poorest regions.Cities in China's interior use tax breaks and cheap land to lure foreign investors.
The mean January temperature at Guiyang is about 41 °F (5 °C).
