Beijing Environmental Protection Bureau has challenged a municipal government official's claim that residents' cooking contributes a large share of the city's PM2.5 pollution. Beijing Youth Daily reported on Thursday that a bureau spokesman said smoke from residents' kitchens accounts for only a small proportion of the pollution. The comments follow those of Zhao Huimin, director of the Beijing Foreign Affairs Office, who urged residents to take part in the city's air pollution control plan, saying smoke from their kitchens adds to the problem.