title: Characterization of a spatial gradient of nitrogen dioxide across a United States-Mexico border city during winter.
abstract: A gradient of ambient nitrogen dioxide (NO(2)) concentration is demonstrated across metropolitan El Paso, Texas (USA), a city located on the international border between the United States and Mexico. Integrated measurements of NO(2) were collected over 7 days at 20 elementary schools and 4 air quality monitoring stations located throughout the city during typical winter atmospheric conditions. Replicate passive monitors were co-located with chemiluminescence analyzers at the monitoring stations for two consecutive 7-day periods. The passive measurements correlated with the analyzer measurements (R(2)=0.74) with precision of 2.5+/-2.2 ppb. Nitrogen dioxide concentrations ranged from 11.0 to 37.5 ppb (mean 20.6+/-7.1 ppb). In a multivariate regression model, the site elevation and distances to a main highway and to an international port of entry from Mexico explained 81% of the variance in the passive measurements. The results of this pilot study indicate that proximity to vehicle-related sources of NO(2) and site elevation are key predictors for future, more detailed assessments of vehicle-related air pollution exposure in the El Paso region.
authors.affiliation: Department of Internal Medicine, University of New Mexico School of Medicine, UNM-LRRI Environmental Health Sciences Center, MSC 10-5550, Albuquerque, NM 87131, USA. mgonzales@salud.unm.edu
authors.forename: Melissa
authors.initials: M
authors.lastname: Gonzales
authors.forename: Clifford
authors.initials: C
authors.lastname: Qualls
authors.forename: Edward
authors.initials: E
authors.lastname: Hudgens
authors.forename: Lucas
authors.initials: L
authors.lastname: Neas
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D002947:Cities; D004784:Environmental Monitoring / Q000379:methods* / Q000706:statistics & numerical data; D005544:Forecasting; D040362:Geographic Information Systems; D016015:Logistic Models; D008800:Mexico; D009585:Nitrogen Dioxide / Q000032:analysis*; D012044:Regression Analysis; D012574:Schools / Q000706:statistics & numerical data; D012621:Seasons; D013781:Texas; D001335:Vehicle Emissions
chemical_list: D000393:Air Pollutants; D001335:Vehicle Emissions; D009585:Nitrogen Dioxide