ust PM2.5 - Total
#&gt; 52   pollutantID         111         Primary PM2.5 - Organic Carbon
#&gt; 53   pollutantID         112       Primary PM2.5 - Elemental Carbon
#&gt; 54   pollutantID         115    Primary PM2.5 - Sulfate Particulate
#&gt; 55   pollutantID         116 Primary PM2.5 -  Brakewear Particulate
#&gt; 56   pollutantID         117  Primary PM2.5 -  Tirewear Particulate
#&gt; 57     processID           1                        Running Exhaust
#&gt; 58     processID           2                