#&gt; 31   pollutantID          21                                Ethanol
#&gt; 32   pollutantID          30                                Ammonia
#&gt; 33   pollutantID          31                        Sulfure Dioxide
#&gt; 34   pollutantID          32                         Nitrogen Oxide
#&gt; 35   pollutantID          33                       Nitrogen Dioxide
#&gt; 36   pollutantID          34                           Nitrous Acid
#&gt; 37   pollutantID          79               Non-Methane Hydroca