Polar Fluxgrams for Air Quality Management

When an airshed is affected by a spatially complex distribution of emitting sources, the angular distribution of tracer fluxes about one or more receptor sites may usefully distinguish the relative contributions of different upwind sources at that site. Such “fluxgrams” complement chemical-mass-balance receptor models to assist decisions affecting optimum emission controls and receptor placement. The technique is illustrated here with B_sp/PM₁₀ in a heavily industrialized valley where, surprisingly, fluxgram analyses show that winter haze exceedances are associated with nighttime winds draining into the industrial lower valley from an upwind residential community.