On 2015 Jan 08, David Mage commented:

Jack Finklea, first Director of the EPA Health Effects Research Laboratory, RTP/NC, wrote here as follows: "We should use what we know in preventive programs and in directing future research. We will make some mistakes when we apply incomplete knowledge, but I think that our need for an excellent scientific information base should not mask the need for society to act on what we do know to clean-up the workplace, and environmental pollution."

The five major mistakes EPA made in setting the first Particulate Matter (PM) National Ambient Air Quality Standard were as follows:

1) The PM standard was for Total Suspended Particulate (TSP) as measured by a highvol sampler that collected all PM with aerodynamic diameters (AD) ranging up to 40 microns. This included PM too large to be inhaled. It was later revised to reflect only respirable PM that were < 10 um and < 2.5 um AD.

2) The first PM NAAQS was 75 ug/m3 TSP as a 1-year geometric mean (GM) based on PMID 6017082. This was a major mistake because two values 5 and 5 have an arithmatic mean (AM) of 5 and a GM of 5 but 0 and 10 have an AM of 5 and a GM of 0! But note, the health effect of {0,10} is greater than the health effect of {5,5}. In addition the GM is not relatable to the dose of inhaled PM even if the total volume of air inhaled during the year were known.

3) The PM NAAQS were, and still are now, based upon the collected mass of the PM, not its molecular composition. From first principles, the cardio-pulmonary toxicity of any PM molecule depends upon its molecular structure and not its molecular weight. Thus if two PM samplers collect the identical number of molecules of the same AD in the same amount of time, EPA would consider the PM collection with the higher average molecular weight to produce more of a health effect (e.g., it is more toxic) than the other collection. This mistake has not been corrected and still underlies virtually all PM studies.

4) All PM NAAQS are based upon the PM concentration measured at an ambient PM monitoring station location meeting various siting and location criteria. Given that no subject spends 24-hours continuously breathing only the ambient air at the station location, the personal PM exposure of all people living in the area will not be numerically equal to the official ambient PM concentration that EPA compares to the NAAQS.

5) The PM NAAQS and all PM epidemiology studies upon which it is based assume the PM health effects follow an ambient PM concentration response relation or a personal PM exposure response relation. They follow neither! They must follow a dose response relation with dose given a value with units specific to the health effect under consideration. For instance: i) if the health effect is systemic, then the dose should be reported as mg/kg-day; ii) if the health effect is related to pulmonary airway surface irritation, then the dose should be reported as mg/m2-day where the mg might, for example, refer to the mass of PM deposited on the non-ciliated sensitive area of alveoli of the pulmonary tract, and m2 refers to that area (not the entire area of the pulmonary tract).

On 2015 Jan 08, David Mage commented:

Jack Finklea, first Director of the EPA Health Effects Research Laboratory, RTP/NC, wrote here as follows: "We should use what we know in preventive programs and in directing future research. We will make some mistakes when we apply incomplete knowledge, but I think that our need for an excellent scientific information base should not mask the need for society to act on what we do know to clean-up the workplace, and environmental pollution."

The five major mistakes EPA made in setting the first Particulate Matter (PM) National Ambient Air Quality Standard were as follows:

1) The PM standard was for Total Suspended Particulate (TSP) as measured by a highvol sampler that collected all PM with aerodynamic diameters (AD) ranging up to 40 microns. This included PM too large to be inhaled. It was later revised to reflect only respirable PM that were < 10 um and < 2.5 um AD.

2) The first PM NAAQS was 75 ug/m3 TSP as a 1-year geometric mean (GM) based on PMID 6017082. This was a major mistake because two values 5 and 5 have an arithmatic mean (AM) of 5 and a GM of 5 but 0 and 10 have an AM of 5 and a GM of 0! But note, the health effect of {0,10} is greater than the health effect of {5,5}. In addition the GM is not relatable to the dose of inhaled PM even if the total volume of air inhaled during the year were known.

3) The PM NAAQS were, and still are now, based upon the collected mass of the PM, not its molecular composition. From first principles, the cardio-pulmonary toxicity of any PM molecule depends upon its molecular structure and not its molecular weight. Thus if two PM samplers collect the identical number of molecules of the same AD in the same amount of time, EPA would consider the PM collection with the higher average molecular weight to produce more of a health effect (e.g., it is more toxic) than the other collection. This mistake has not been corrected and still underlies virtually all PM studies.

4) All PM NAAQS are based upon the PM concentration measured at an ambient PM monitoring station location meeting various siting and location criteria. Given that no subject spends 24-hours continuously breathing only the ambient air at the station location, the personal PM exposure of all people living in the area will not be numerically equal to the official ambient PM concentration that EPA compares to the NAAQS.

5) The PM NAAQS and all PM epidemiology studies upon which it is based assume the PM health effects follow an ambient PM concentration response relation or a personal PM exposure response relation. They follow neither! They must follow a dose response relation with dose given a value with units specific to the health effect under consideration. For instance: i) if the health effect is systemic, then the dose should be reported as mg/kg-day; ii) if the health effect is related to pulmonary airway surface irritation, then the dose should be reported as mg/m2-day where the mg might, for example, refer to the mass of PM deposited on the non-ciliated sensitive area of alveoli of the pulmonary tract, and m2 refers to that area (not the entire area of the pulmonary tract).