title: The effect of particle size on cardiovascular disorders--the smaller the worse.
abstract: BACKGROUND
  Previous studies observed associations between airborne particles and cardio-vascular disease. Questions, however, remain as to which size of the inhalable particles (coarse, fine, or ultrafine) exerts the most significant impact on health.
  
  
  METHODS
  For this retrospective study, data of the total number of 23,741 emergency service calls, registered between February 2002 and January 2003 in the City of Leipzig, were analysed, identifying 5326 as being related to cardiovascular incidences. Simultaneous particle exposure was determined for the particle sizes classes <100 nm (UFP), <2.5 μm (PM2.5) and <10 μm (PM10). We used a time resolution of 1 day for both parameters, emergency calls and exposure.
  
  
  RESULTS
  Within the group of cardiovascular diseases, the diagnostic category of hypertensive crisis showed a significant association with particle exposure. The significant effect on hypertensive crisis was found for particles with a size of <100 nm in diameter and starting with a lag of 2 days after exposure. No consistent influence could be observed for PM2.5 and PM10. The Odds Ratios on hypertensive crisis were significant for the particle size <100 nm in diameter from day 2 post exposure OR=1.06 (95%CI: 1.02-1.10, p=0.002) up to day 7 OR=1.05 (95%CI 1.02-1.09, p=0.005).
  
  
  CONCLUSIONS
  Ultrafine particles affect cardiovascular disease adversely, particularly hypertensive crises. Their effect is significant compared with PM2.5 and PM10. It appears necessary, from a public health point of view, to consider regulating this type of particles using appropriate measurands as particle number.
authors.affiliation: Helmholtz Centre for Environmental Research GmbH - UFZ, Leipzig, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Franck
authors.forename: Siad
authors.initials: S
authors.lastname: Odeh
authors.forename: Alfred
authors.initials: A
authors.lastname: Wiedensohler
authors.forename: Birgit
authors.initials: B
authors.lastname: Wehner
authors.forename: Olf
authors.initials: O
authors.lastname: Herbarth
mesh_terms: D000328:Adult; D000393:Air Pollutants / Q000032:analysis / Q000737:chemistry / Q000633:toxicity*; D002318:Cardiovascular Diseases / Q000139:chemically induced* / Q000453:epidemiology; D002947:Cities; D003627:Data Interpretation, Statistical; D004632:Emergency Medical Services / Q000706:statistics & numerical data; D004784:Environmental Monitoring; D062665:Epidemiological Monitoring; D005260:Female; D005858:Germany; D006801:Humans; D008297:Male; D008875:Middle Aged; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis / Q000737:chemistry / Q000633:toxicity*; D012189:Retrospective Studies
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter