                      Sampled onto PCTE filters                     0                     0                           0                                 \_                                           Outdoor air, vacant, PM~00~                        Sampled onto PCTE filters                     0                     0                           0                                 \_                                           Outdoor air, vacant, PM~0.0~                       Sampled onto PCTE filters                     0                     0                           0                                 \_   