Size-Fractionated Particle Number Concentrations and Daily Mortality in a Chinese City

Background: Associations between airborne particles and health outcomes have been documented worldwide; however, there is limited information regarding health effects associated with different particle sizes. Objectives: We explored the association between size-fractionated particle number concentrations (PNCs) and daily mortality in Shenyang, China. Methods: We collected daily data on cause-specific mortality and PNCs for particles measuring 0.25–10 μm in diameter between 1 December 2006 and 30 November 2008. We used quasi-Poisson regression generalized additive models to estimate associations between PNCs and mortality, and we used natural spline smoothing functions to adjust for time-varying covariates and long-term and seasonal trends. Results: Mean numbers of daily deaths were 67, 32, and 7 for all natural causes, cardiovascular diseases, and respiratory diseases, respectively. Interquartile range (IQR) increases in PNCs for particles measuring 0.25–0.50 μm were significantly associated with total and cardiovascular mortality, but not respiratory mortality. Effect estimates were larger for PNCs during the warm season than the cool season, and increased with decreasing particle size. IQR increases in PNCs of 0.25–0.28 μm, 0.35–0.40 μm, and 0.45–0.50 μm particles were associated with 2.41% (95% CI: 1.23, 3.58%), 1.31% (95% CI: 0.52, 2.09%), and 0.45% (95% CI: 0.04, 0.87%) higher total mortality, respectively. Associations were generally stable after adjustment for mass concentrations of ambient particles and gaseous pollutants. Conclusions: Our findings suggest that particles < 0.5 μm in diameter may be most responsible for adverse health effects of particulate air pollution and that adverse health effects may increase with decreasing particle size. Citation: Meng X, Ma Y, Chen R, Zhou Z, Chen B, Kan H. 2013. Size-fractionated particle number concentrations and daily mortality in a Chinese city. Environ Health Perspect 121:1174–1178; http://dx.doi.org/10.1289/ehp.1206398

[1]  O. Raaschou-Nielsen,et al.  Size distribution and total number concentration of ultrafine and accumulation mode particles and hospital admissions in children and the elderly in Copenhagen, Denmark , 2007, Occupational and Environmental Medicine.

[2]  Annette Peters,et al.  Spatial and temporal variation of particle number concentration in Augsburg, Germany. , 2008, The Science of the total environment.

[3]  Kaarle Hämeri,et al.  Spatial variation of aerosol number concentration in Helsinki city , 1999 .

[4]  Roger D Peng,et al.  On time series analysis of public health and biomedical data. , 2006, Annual review of public health.

[5]  Uwe Schlink,et al.  Associations between size-segregated particle number concentrations and respiratory mortality in Beijing, China , 2012, International journal of environmental health research.

[6]  A. Peters,et al.  Respiratory effects are associated with the number of ultrafine particles. , 1997, American journal of respiratory and critical care medicine.

[7]  H. Kan,et al.  Health Impact of Outdoor Air Pollution in China: Current Knowledge and Future Research Needs , 2009, Environmental health perspectives.

[8]  W G Kreyling,et al.  Daily mortality and fine and ultrafine particles in Erfurt, Germany part I: role of particle number and particle mass. , 2000, Research report.

[9]  T S Nawrot,et al.  Stronger associations between daily mortality and fine particulate air pollution in summer than in winter: evidence from a heavily polluted region in western Europe , 2007, Journal of Epidemiology and Community Health.

[10]  Wei Huang,et al.  Association of particulate air pollution with daily mortality: the China Air Pollution and Health Effects Study. , 2012, American journal of epidemiology.

[11]  Francesca Dominici,et al.  Coarse particulate matter air pollution and hospital admissions for cardiovascular and respiratory diseases among Medicare patients. , 2008, JAMA.

[12]  Brämer Gr.  International statistical classification of diseases and related health problems. Tenth revision. , 1988, World health statistics quarterly. Rapport trimestriel de statistiques sanitaires mondiales.

[13]  B. Brunekreef,et al.  Epidemiological evidence of effects of coarse airborne particles on health , 2005, European Respiratory Journal.

[14]  Ilias G. Kavouras,et al.  Spatial variation of particle number and mass over four European cities , 2007 .

[15]  G. Braemer.  International statistical classification of diseases and related health problems. Tenth revision. , 1988, World health statistics quarterly. Rapport trimestriel de statistiques sanitaires mondiales.

[16]  A. Valavanidis,et al.  Airborne Particulate Matter and Human Health: Toxicological Assessment and Importance of Size and Composition of Particles for Oxidative Damage and Carcinogenic Mechanisms , 2008, Journal of environmental science and health. Part C, Environmental carcinogenesis & ecotoxicology reviews.

[17]  J. Schwartz,et al.  Are there sensitive subgroups for the effects of airborne particles? , 2000, Environmental health perspectives.

[18]  F. Dominici,et al.  Time-series studies of particulate matter. , 2004, Annual review of public health.

[19]  A. Peters,et al.  Sub-micrometer particulate air pollution and cardiovascular mortality in Beijing, China. , 2011, The Science of the total environment.

[20]  Constantinos Sioutas,et al.  Potential Role of Ultrafine Particles in Associations between Airborne Particle Mass and Cardiovascular Health , 2005, Environmental health perspectives.

[21]  Wolfgang Kreyling,et al.  Epidemiological evidence on health effects of ultrafine particles. , 2002, Journal of aerosol medicine : the official journal of the International Society for Aerosols in Medicine.

[22]  D. Corrado,et al.  Cardiovascular causes of sudden death in young individuals including athletes. , 1999, Cardiology in review.

[23]  Haidong Kan,et al.  Public Health and Air Pollution in Asia (PAPA): A Multicity Study of Short-Term Effects of Air Pollution on Mortality , 2008, Environmental health perspectives.

[24]  Bert Brunekreef,et al.  Particulate Air Pollution and Risk of ST-Segment Depression During Repeated Submaximal Exercise Tests Among Subjects With Coronary Heart Disease: The Exposure and Risk Assessment for Fine and Ultrafine Particles in Ambient Air (ULTRA) Study , 2002, Circulation.

[25]  H. Kan,et al.  Coarse particles and mortality in three Chinese cities: the China Air Pollution and Health Effects Study (CAPES). , 2011, The Science of the total environment.

[26]  F. Dominici,et al.  Fine particulate air pollution and hospital admission for cardiovascular and respiratory diseases. , 2006, JAMA.

[27]  H. Kan,et al.  Temperature modifies the acute effect of particulate air pollution on mortality in eight Chinese cities. , 2012, The Science of the total environment.

[28]  A. Peters,et al.  Daily mortality and particulate matter in different size classes in Erfurt, Germany , 2007, Journal of Exposure Science and Environmental Epidemiology.

[29]  W. Wilson,et al.  Fine particles and coarse particles: concentration relationships relevant to epidemiologic studies. , 1997, Journal of the Air & Waste Management Association.