Recent studies associate 24 hr PM10 levels within EPA's 150 mug/M3 standard with significantly morbidity and mortality.
These findings remain unexplained toxicologically.
This study documents the contribution of brief airborne particle excursions to 24 hr average particle levels, and evaluates the possible public health significance of such excursions.
Two proven technologies-inertial and beta attenuation-were identified for continuously monitoring particle mass.
Ten 24 hr periods distributed among three locations were examined with PM10<150 mug/M3.
At all three locations, and in six of ten days, excursions exceeded 150 mug/M3.
Excursions of 15 min reached 2000 mug/M3, surpassing the 1952 London for (PM10 ¾ 1200 mug/M3) and refuting EPA's assumption that 24 hr averaging protects against excursions.
Toxicology literature confirmed the harmfulness of airborne particles in the range of observed excursions.
In contrast, EPA has assumed that protracted post-exposure morbidity and mortality are explainable by protracted rather than short-term causes.
This study suggests that known toxicological mechanisms involving brief but intense particle mass excursions might cause the unexplained effects.
EPA has advocated rejecting a 1 hr particle standard, citing uncertainty that « the majority of effects » observe after daily exposure would occur after briefer exposures. (...)
Mots-clés Pascal : Pollution air, Aérosol, Particule en suspension, Exposition, Norme qualité air, Zone urbaine, Protection pollution air
Mots-clés Pascal anglais : Air pollution, Aerosols, Suspended particle, Exposure, Air quality standard, Urban area, Air pollution control
Notice produite par :
Inist-CNRS - Institut de l'Information Scientifique et Technique
Cote : 97-0012901
Code Inist : 001D16C06. Création : 21/05/1997.