After calling my mother, she told me that when she is younger, the morning fog was very misty, even more than the ones i remember. It was very white as well, before any factories was built around Beijing. She loved it when she is little because playing in the fog was like playing in heaven, where all the goddess flying around in the clouds. She would imagine she was one of them in the sky. When the sun raises a few moment later, the sunlight would price through the mist, splashing its orange light to various color. She told me that it was like running in the dazzling air full of tiny crystals. Even though  the heavy fog still exist today, as the ones I remember, she said it is not as clear and refreshing as the one she grew up with.The air pollution that gradually build up in Beijing is visible in the morning fog through different generations.