title: Satellite-Based Estimates of Long-Term Exposure to Fine Particles and Association with Mortality in Elderly Hong Kong Residents.
abstract: BACKGROUND
  A limited number of studies on long-term effects of particulate matter with aerodynamic diameter < 2.5 μm (PM2.5) on health suggest it can be an important cause of morbidity and mortality. In Asia where air quality is poor and deteriorating, local data on long-term effects of PM2.5 to support policy on air quality management are scarce.
  
  
  OBJECTIVE
  We assessed long-term effects of PM2.5 on the mortality in a single Asian city.
  
  
  METHODS
  For 10-13 years, we followed up a cohort of 66,820 participants ≥ 65 years of age who were enrolled and interviewed in all 18 Elderly Health Centres of the Department of Health, Hong Kong, in 1998-2001. Their residential addresses were geocoded into x- and y-coordinates, and their proxy exposures to PM2.5 at their addresses in 1 × 1 km grids were estimated from the U.S. National Aeronautics and Space Administration (NASA) satellite data. We used Cox regression models to calculate hazard ratios (HRs) of mortality associated with PM2.5.
  
  
  RESULTS
  Mortality HRs per 10-μg/m3 increase in PM2.5 were 1.14 (95% CI: 1.07, 1.22) for all natural causes, 1.22 (95% CI: 1.08, 1.39) for cardiovascular causes, 1.42 (95% CI: 1.16, 1.73) for ischemic heart disease, 1.24 (95% CI: 1.00, 1.53) for cerebrovascular disease, and 1.05 (95% CI: 0.90, 1.22) for respiratory causes.
  
  
  CONCLUSIONS
  Our methods in using NASA satellite data provide a readily accessible and affordable approach to estimation of a sufficient range of individual PM2.5 exposures in a single city. This approach can expand the capacity to conduct environmental accountability studies in areas with few measurements of fine particles.
  
  
  BACKGROUND
  Wong CM, Lai HK, Tsang H, Thach TQ, Thomas GN, Lam KB, Chan KP, Yang L, Lau AK, Ayres JG, Lee SY, Chan WM, Hedley AJ, Lam TH. 2015. Satellite-based estimates of long-term exposure to fine particles and association with mortality in elderly Hong Kong residents. Environ Health Perspect 123:1167-1172; http://dx.doi.org/10.1289/ehp.1408264.
authors.affiliation: School of Public Health, The University of Hong Kong, Hong Kong, China.
authors.forename: Chit Ming
authors.initials: CM
authors.lastname: Wong
authors.forename: Hak Kan
authors.initials: HK
authors.lastname: Lai
authors.forename: Hilda
authors.initials: H
authors.lastname: Tsang
authors.forename: Thuan Quoc
authors.initials: TQ
authors.lastname: Thach
authors.forename: G Neil
authors.initials: GN
authors.lastname: Thomas
authors.forename: Kin Bong Hubert
authors.initials: KB
authors.lastname: Lam
authors.forename: King Pan
authors.initials: KP
authors.lastname: Chan
authors.forename: Lin
authors.initials: L
authors.lastname: Yang
authors.forename: Alexis K H
authors.initials: AK
authors.lastname: Lau
authors.forename: Jon G
authors.initials: JG
authors.lastname: Ayres
authors.forename: Siu Yin
authors.initials: SY
authors.lastname: Lee
authors.forename: Wai Man
authors.initials: WM
authors.lastname: Chan
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Hedley
authors.forename: Tai Hing
authors.initials: TH
authors.lastname: Lam
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000397:Air Pollution / Q000009:adverse effects; D002318:Cardiovascular Diseases / Q000401:mortality*; D002561:Cerebrovascular Disorders / Q000401:mortality*; D015331:Cohort Studies; D005260:Female; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D008297:Male; D009026:Mortality; D052638:Particulate Matter / Q000633:toxicity*; D012140:Respiratory Tract Diseases / Q000401:mortality*; D063809:Satellite Imagery; D014481:United States; D018557:United States National Aeronautics and Space Administration
chemical_list: D052638:Particulate Matter