According to the South Coast Air Quality Management District (SCAQMD), the sample for Site #19 on May 1st was not collected: it was used for an off-schedule sample that was collected on May 3rd. Due to the off-schedule sample on May 3rd, the typical May 4th sample was not collected. The normal schedule for sampling will resume on May 7th. SCAQMD is preparing another sampler so they do not have to alter the schedule for Site #19 to collect on off-schedule sample in the future.
Additionally, the portable City samplers should not have been marked on the ambient data spreadsheet. They will be removed, as the City monitor would not have been at Site #19 after the initial sample. The portable samplers are being implemented into the rotation of SCAQMD samplers. The agency will clarify this on their Expanded Monitoring Data and Map spreadsheet.