title: Spatial variability in levels of benzene, formaldehyde, and total benzene, toluene, ethylbenzene and xylenes in New York City: a land-use regression study.
abstract: BACKGROUND
  Hazardous air pollutant exposures are common in urban areas contributing to increased risk of cancer and other adverse health outcomes. While recent analyses indicate that New York City residents experience significantly higher cancer risks attributable to hazardous air pollutant exposures than the United States as a whole, limited data exist to assess intra-urban variability in air toxics exposures.
  
  
  METHODS
  To assess intra-urban spatial variability in exposures to common hazardous air pollutants, street-level air sampling for volatile organic compounds and aldehydes was conducted at 70 sites throughout New York City during the spring of 2011. Land-use regression models were developed using a subset of 59 sites and validated against the remaining 11 sites to describe the relationship between concentrations of benzene, total BTEX (benzene, toluene, ethylbenzene, xylenes) and formaldehyde to indicators of local sources, adjusting for temporal variation.
  
  
  RESULTS
  Total BTEX levels exhibited the most spatial variability, followed by benzene and formaldehyde (coefficient of variation of temporally adjusted measurements of 0.57, 0.35, 0.22, respectively). Total roadway length within 100 m, traffic signal density within 400 m of monitoring sites, and an indicator of temporal variation explained 65% of the total variability in benzene while 70% of the total variability in BTEX was accounted for by traffic signal density within 450 m, density of permitted solvent-use industries within 500 m, and an indicator of temporal variation. Measures of temporal variation, traffic signal density within 400 m, road length within 100 m, and interior building area within 100 m (indicator of heating fuel combustion) predicted 83% of the total variability of formaldehyde. The models built with the modeling subset were found to predict concentrations well, predicting 62% to 68% of monitored values at validation sites.
  
  
  CONCLUSIONS
  Traffic and point source emissions cause substantial variation in street-level exposures to common toxic volatile organic compounds in New York City. Land-use regression models were successfully developed for benzene, formaldehyde, and total BTEX using spatial indicators of on-road vehicle emissions and emissions from stationary sources. These estimates will improve the understanding of health effects of individual pollutants in complex urban pollutant mixtures and inform local air quality improvement efforts that reduce disparities in exposure.
authors: New York City Department of Health and Mental Hygiene, Bureau of Environmental Surveillance and Policy, 125 Worth Street, CN34E, New York, NY 10013, USA. ikheirbe@health.nyc.gov
authors: Iyad
authors: I
authors: Kheirbek
authors: Sarah
authors: S
authors: Johnson
authors: Zev
authors: Z
authors: Ross
authors: Grant
authors: G
authors: Pezeshki
authors: Kazuhiko
authors: K
authors: Ito
authors: Holger
authors: H
authors: Eisl
authors: Thomas
authors: T
authors: Matte
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D001555:Benzene Derivatives / Q000032:analysis*; D004781:Environmental Exposure; D004784:Environmental Monitoring / Q000379:methods*; D005557:Formaldehyde / Q000032:analysis*; D006802:Human Activities; D006801:Humans; D008962:Models, Theoretical; D009519:New York City; D012044:Regression Analysis
chemical_list: D000393:Air Pollutants; D001555:Benzene Derivatives; D005557:Formaldehyde