Error(s) in re-building vignettes:
--- re-building ‘Air_Quality.Rmd’ using rmarkdown
Pandoc is required to build R Markdown vignettes but not available. Please make sure it is installed.
--- finished re-building ‘Air_Quality.Rmd’

--- re-building ‘Atmospheric_Radiation.Rmd’ using rmarkdown
Pandoc is required to build R Markdown vignettes but not available. Please make sure it is installed.
--- finished re-building ‘Atmospheric_Radiation.Rmd’

--- re-building ‘Basic_Functions.Rmd’ using rmarkdown
Pandoc is required to build R Markdown vignettes but not available. Please make sure it is installed.
--- finished re-building ‘Basic_Functions.Rmd’

--- re-building ‘Particle_Size_Distribution.Rmd’ using rmarkdown
Pandoc is required to build R Markdown vignettes but not available. Please make sure it is installed.
Quitting from lines 47-48 (Particle_Size_Distribution.Rmd) 
Error: processing vignette 'Particle_Size_Distribution.Rmd' failed with diagnostics:
polygon edge not found
--- failed re-building ‘Particle_Size_Distribution.Rmd’

--- re-building ‘Plot_Functions.Rmd’ using rmarkdown
Pandoc is required to build R Markdown vignettes but not available. Please make sure it is installed.
Scale for 'y' is already present. Adding another scale for 'y', which will
replace the existing scale.
Scale for 'x' is already present. Adding another scale for 'x', which will
replace the existing scale.
Scale for 'y' is already present. Adding another scale for 'y', which will
replace the existing scale.
Scale for 'x' is already present. Adding another scale for 'x', which will
replace the existing scale.
Scale for 'y' is already present. Adding another scale for 'y', which will
replace the existing scale.
Scale for 'x' is already present. Adding another scale for 'x', which will
replace the existing scale.
Scale for 'y' is already present. Adding another scale for 'y', which will
replace the existing scale.
Scale for 'x' is already present. Adding another scale for 'x', which will
replace the existing scale.
Scale for 'y' is already present. Adding another scale for 'y', which will
replace the existing scale.
Scale for 'x' is already present. Adding another scale for 'x', which will
replace the existing scale.
Scale for 'y' is already present. Adding another scale for 'y', which will
replace the existing scale.
Scale for 'x' is already present. Adding another scale for 'x', which will
replace the existing scale.
Scale for 'y' is already present. Adding another scale for 'y', which will
replace the existing scale.
Scale for 'x' is already present. Adding another scale for 'x', which will
replace the existing scale.
Scale for 'y' is already present. Adding another scale for 'y', which will
replace the existing scale.
Scale for 'x' is already present. Adding another scale for 'x', which will
replace the existing scale.
Scale for 'y' is already present. Adding another scale for 'y', which will
replace the existing scale.
Scale for 'x' is already present. Adding another scale for 'x', which will
replace the existing scale.
Scale for 'y' is already present. Adding another scale for 'y', which will
replace the existing scale.
Scale for 'x' is already present. Adding another scale for 'x', which will
replace the existing scale.
Scale for 'y' is already present. Adding another scale for 'y', which will
replace the existing scale.
Scale for 'x' is already present. Adding another scale for 'x', which will
replace the existing scale.
Warning: Removed 480 rows containing missing values (geom_point).
Warning in grid.Call(C_stringMetric, as.graphicsAnnot(x$label)) :
  no font could be found for family "TT Arial"
Warning in grid.Call(C_stringMetric, as.graphicsAnnot(x$label)) :
  no font could be found for family "TT Arial"
Warning in grid.Call(C_stringMetric, as.graphicsAnnot(x$label)) :
  no font could be found for family "TT Arial"
Warning in grid.Call(C_stringMetric, as.graphicsAnnot(x$label)) :
  no font could be found for family "TT Arial"
Warning in grid.Call(C_stringMetric, as.graphicsAnnot(x$label)) :
  no font could be found for family "TT Arial"
Warning in grid.Call(C_stringMetric, as.graphicsAnnot(x$label)) :
  no font could be found for family "TT Arial"
Warning in grid.Call(C_stringMetric, as.graphicsAnnot(x$label)) :
  no font could be found for family "TT Arial"
Warning in grid.Call(C_stringMetric, as.graphicsAnnot(x$label)) :
  no font could be found for family "TT Arial"
Warning in grid.Call(C_stringMetric, as.graphicsAnnot(x$label)) :
  no font could be found for family "TT Arial"
Warning in grid.Call(C_stringMetric, as.graphicsAnnot(x$label)) :
  no font could be found for family "TT Arial"
Warning in grid.Call(C_stringMetric, as.graphicsAnnot(x$label)) :
  no font could be found for family "TT Arial"
Warning in grid.Call(C_stringMetric, as.graphicsAnnot(x$label)) :
  no font could be found for family "TT Arial"
Warning in grid.Call(C_stringMetric, as.graphicsAnnot(x$label)) :
  no font could be found for family "TT Arial"
Warning in grid.Call(C_stringMetric, as.graphicsAnnot(x$label)) :
  no font could be found for family "TT Arial"
Warning in grid.Call(C_textBounds, as.graphicsAnnot(x$label), x$x, x$y,  :
  no font could be found for family "TT Arial"
Quitting from lines 346-347 (Plot_Functions.Rmd) 
Error: processing vignette 'Plot_Functions.Rmd' failed with diagnostics:
polygon edge not found
--- failed re-building ‘Plot_Functions.Rmd’

--- re-building ‘Trace_Gas_Chemistry.Rmd’ using rmarkdown
Pandoc is required to build R Markdown vignettes but not available. Please make sure it is installed.
--- finished re-building ‘Trace_Gas_Chemistry.Rmd’

SUMMARY: processing the following files failed:
  ‘Particle_Size_Distribution.Rmd’ ‘Plot_Functions.Rmd’

Error: Vignette re-building failed.
Execution halted