摘要
OPENING the window and seeing rolling gray smog is a frequent reality in Beijing and other major cities in China. Whether emanating from vehicle exhaust pipes or the thick plumes of black smoke rising from industrial smokestacks, air pollution has become one of the key frustrations of China＇s urban residents. With the increasing frequency of smoggy days, the spotlight on the issue has never burned brighter. Terms like PM2.5 levels （solid particles and water/oil based aerosols less than 2.5 micrometers in diameter） are no longer restricted to scientists. Smart phone apps that allow users to check pollutant levels help anyone with an know when the air quality or just plain dangerous.
OPENING the window and seeing rolling gray smog is a frequent reality in Beijing and other major cities in China. Whether emanating from vehicle exhaust pipes or the thick plumes of black smoke rising from industrial smokestacks, air pollution has become one of the key frustrations of China＇s urban residents. With the increasing frequency of smoggy days, the spotlight on the issue has never burned brighter. Terms like PM2.5 levels （solid particles and water/oil based aerosols less than 2.5 micrometers in diameter） are no longer restricted to scientists. Smart phone apps that allow users to check pollutant levels help anyone with an know when the air quality or just plain dangerous.
