The air pollution mask can be a solution for short-medium term in my opinion. I saw a lot of similar products on amazon.com. As you said in big cities, especially from China where the pollution level is very high. Unfortunately, this affects our life, instead of enjoying the nature, the stone surrounded us. I live in the biggest city from Romania, but the pollution level cannot compare with the Chinese cities level. I prefer to live in a healthier city, with less pollution even I would work for less money :)