title: Fine particle components and health--a systematic review and meta-analysis of epidemiological time series studies of daily mortality and hospital admissions.
abstract: Short-term exposure to fine particle mass (PM) has been associated with adverse health effects, but little is known about the relative toxicity of particle components. We conducted a systematic review to quantify the associations between particle components and daily mortality and hospital admissions. Medline, Embase and Web of Knowledge were searched for time series studies of sulphate (SO4(2-)), nitrate (NO3(-)), elemental and organic carbon (EC and OC), particle number concentrations (PNC) and metals indexed to October 2013. A multi-stage sifting process identified eligible studies and effect estimates for meta-analysis. SO4(2-), NO3(-), EC and OC were positively associated with increased all-cause, cardiovascular and respiratory mortality, with the strongest associations observed for carbon: 1.30% (95% CI: 0.17%, 2.43%) increase in all-cause mortality per 1 μg/m(3). For PNC, the majority of associations were positive with confidence intervals that overlapped 0%. For metals, there were insufficient estimates for meta-analysis. There are important gaps in our knowledge of the health effects associated with short-term exposure to particle components, and the literature also lacks sufficient geographical coverage and analyses of cause-specific outcomes. The available evidence suggests, however, that both EC and secondary inorganic aerosols are associated with adverse health effects.
authors.affiliation: Population Health Research Institute and MRC-PHE Centre for Environment and Health, St George's, University of London, London, UK.
authors.forename: Richard W
authors.initials: RW
authors.lastname: Atkinson
authors.affiliation: Public Health England, Centre for Radiation, Chemical and Environmental Hazards, Chilton, Oxfordshire, UK.
authors.forename: Inga C
authors.initials: IC
authors.lastname: Mills
authors.affiliation: 1] MRC-PHE Centre for Environment and Health, King's College London, London, UK [2] NIHR Biomedical Research Centre at Guy's and St Thomas' NHS Foundation Trust and King's College London, London, UK.
authors.forename: Heather A
authors.initials: HA
authors.lastname: Walton
authors.affiliation: 1] Population Health Research Institute and MRC-PHE Centre for Environment and Health, St George's, University of London, London, UK [2] MRC-PHE Centre for Environment and Health, King's College London, London, UK.
authors.forename: H Ross
authors.initials: HR
authors.lastname: Anderson
mesh_terms: D000336:Aerosols / Q000009:adverse effects; D000393:Air Pollutants / Q000009:adverse effects*; D000397:Air Pollution / Q000009:adverse effects; D002244:Carbon / Q000009:adverse effects; D002318:Cardiovascular Diseases / Q000401:mortality*; D016208:Databases, Factual; D006760:Hospitalization; D006801:Humans; D008171:Lung Diseases / Q000401:mortality*; D009566:Nitrates / Q000009:adverse effects; D010316:Particle Size; D052638:Particulate Matter / Q000009:adverse effects*; D013431:Sulfates / Q000009:adverse effects; D013997:Time Factors
chemical_list: D000336:Aerosols; D000393:Air Pollutants; D009566:Nitrates; D052638:Particulate Matter; D013431:Sulfates; D002244:Carbon