@article{148256,
  author = {J. Liu and D. L. Mauzerall},
  title = {Estimating the Average Time for Inter-continental Transport of Air Pollutants},
  abstract = { We estimate the average time required for intercontinental transport of atmospheric tracers based on simulations with the global chemical tracer model MOZART-2 driven with NCEP meteorology. We represent the average transport time by a ratio of the concentration of two tracers with different lifetimes. We find that average transport times increase with tracer lifetimes. With tracers of 1- and 2-week lifetimes the average transport time from East Asia (EA) to the surface of western North America (NA) in April is 2 {\textendash} 3 weeks, approximately a half week longer than transport from NA to western Europe (EU) and from EU to EA. We develop an {\textquoteleft}equivalent circulation{\textquoteright} method to estimate a timescale which has little dependence on tracer lifetimes and obtain similar results to those obtained with short-lived tracers. Our findings show that average intercontinental transport times, even for tracers with short lifetimes, are on average 1 {\textendash} 2 weeks longer than rapid transport observed in plumes. },
  year = {2005},
  journal = {Geophysical Research Letters},
  volume = {32},
  doi = {10.1029/2005GL022619},
  language = {eng},
}