Aerosol particles suspended in the air of urban environments typically reduce visibility, interact with sunlight by scattering and absorbing radiation, and lower air quality. In addition, these tiny particles can also contribute large pollution plumes, called “brown clouds”, which have been observed to originate over South Asia in recent years and undergo long distance transport by the wind to reach other continents. The particles in brown clouds are composed by an unhealthy and variable mix including ozone and organic molecules found in smoke.