LITTLE Kwok Yu-hin is a victim of the territory's filthy air. And the six-year-old will have to learn to cope because the dirt will always be there, said his mother, Kwok Chak Lai-wa, as she took him to the doctor in Kwun Tong yesterday. Yu-hin was born with a weak respiratory system and his allergies cause coughing fits when dry weather raises dust levels. 'The doctor said his lungs would get stronger after he reached five and now he is six, so I think he has stronger resistance than before,' said 33-year-old Mrs Kwok, adding, however, that Yu-hin had been coughing for the last few days. 'I can't make him stay at home whenever the air is bad. He has to get used to this kind of weather,' added Mrs Kwok, who lives in Sai Kung. Meanwhile, the Environmental Protection Department yesterday calculated the air pollution index for industrial Kwun Tong at 82 - 'moderate' - slightly lower than the previous day's record level for the year. It is forecast to be better today, ranging between 65 and 75. The problem is worst at this time of year as the dry air lets the dust float rather than being washed out by rain or humidity. Clerk Mau Wai-mun, 33, always carries a handkerchief to cover her nose and keep out the traffic fumes. She blamed vehicles and construction sites for the dust, and said she could smell the fumes from plastics factories. 'I think the construction sites here should clear up the dust and splash water on the ground. This stops dust from flying up when vehicles pass by,' she said. Newspaper seller Fung Lam Siu-tsui, 34, has been operating her newsstand for almost 20 years in Hoi Yuen Road, Kwun Tong. She has seen the pollution change - but not improve. 'A few years ago, it was the acidic fumes which spread all over from the dyeing factories. But since most of them have moved, it is now the vehicles which emit dust,' she said.