title: Using subscript and variable values at the same time in Axis titles in R
body: <p>I want to use the title "CO2 emissions in wetlands" in a plot in R, whereas the 2 in CO2 is in subscript, and the value for the region (here: "wetlands") is contained in a variable named "region".</p>
  
  <pre><code>region = "wetlands"
  plot (1, 1, main=expression(CO[2]~paste(" emissions in ", region)))
  </code></pre>
  
  <p>The problem is, that not the value of the variable is pasted, but the name of the variable. This gives "CO2 emissions in region" instead of "CO2 emissions in wetlands". I also tried:</p>
  
  <pre><code>region="wetlands"
  plot (1,1,main=paste(expression(CO[2]), "emissions in", region))
  </code></pre>
  
  <p>But the subscript is not done here, and the title is: "CO[2] emissions in wetlands".</p>
  
  <p>Is it somehow possible to get values of variables into expression?</p>
  
  <p>Thanks for your help,</p>
  
  <p>Sven</p>