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Table 1 Calculated spatial extent from illustrative case study under differing assumptions and definitions

From: Factors influencing the spatial extent of mobile source air pollution impacts: a meta-analysis

Factor under study Emission rate (μg/m·s) Background concentration (μg/m3) Meteorological conditions Definition of spatial extent Estimated spatial extent (m)
    Wind speed (m/s) Stability class Comparison method Threshold  
Spatial extent definition 5 0 4 D Absolute 0.25 μg/m3 70
  5 0 4 D Absolute 0.1 μg/m3 190
  5 0 4 D Absolute 0.05 μg/m3 430
  5 0 4 D Relative 50% of reference 60
  5 0 4 D Relative 20% of reference 170
  5 0 4 D Relative 10% of reference 380
Emission rate 2.5 0 4 D Absolute 0.1 μg/m3 90
  10 0 4 D Absolute 0.1 μg/m3 430
Background concentration 5 0.25 4 D Relative 50% of reference 120
  5 1 4 D Relative 50% of reference N/A
Meteorological factor 5 0 3 F Absolute 0.25 μg/m3 350
  5 0 2 B Absolute 0.25 μg/m3 70
  5 0 6 D Absolute 0.25 μg/m3 40
Health risk threshold 5 0 4 D Absolute 20 per million cancer risk 300
  5 0 4 D Absolute 1 per million cancer risk > 500 (beyond domain)