BackgroundCharacterizing intra-urban variation in air quality is important for epidemiological investigation of health outcomes and disparities. To date, however, few studies have been designed to capture spatial variation during select hours of the day, or to examine the roles of meteorology and complex terrain in shaping intra-urban exposure gradients.MethodsWe designed a spatial saturation monitoring study to target local air pollution sources, and to understand the role of topography and temperature inversions on fine-scale pollution variation by systematically allocating sampling locations across gradients in key local emissions sources (vehicle traffic, industrial facilities) and topography (elevation) in the Pittsburgh area. Street-level integrated samples of fine particulate matter (PM2.5), black carbon (BC), nitrogen dioxide (NO2), sulfur dioxide (SO2), and ozone (O3) were collected during morning rush and probable inversion hours (6-11 AM), during summer and winter. We hypothesized that pollution concentrations would be: 1) higher under inversion conditions, 2) exacerbated in lower-elevation areas, and 3) vary by season.ResultsDuring July - August 2011 and January - March 2012, we observed wide spatial and seasonal variability in pollution concentrations, exceeding the range measured at regulatory monitors. We identified elevated concentrations of multiple pollutants at lower-elevation sites, and a positive association between inversion frequency and NO2 concentration. We examined temporal adjustment methods for deriving seasonal concentration estimates, and found that the appropriate reference temporal trend differs between pollutants.ConclusionsOur time-stratified spatial saturation approach found some evidence for modification of inversion-concentration relationships by topography, and provided useful insights for refining and interpreting GIS-based pollution source indicators for Land Use Regression modeling.

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Background:The Spiroscout is a small, portable unit that attaches easily to most metered dose inhalers, determines the time and location of use, and wirelessly communicates that information to a remote server. Our study defines asthma exacerbation using this novel combined clinical end point. Objectives:Our study was designed to field test the Spiroscout and explore the potential relationship between childhood asthma morbidity and combined impacts from traffic, industrial and regional background accumulation and indoor pollution exposures. Methods:The Spiroscout was piloted in ~15 homes of asthmatic children residing in and around Braddock, PA, in summer 2011 and winter 2012. In addition to this unique health endpoint, one week indoor PM2.5, NOx, temperature and humidity measurements and corresponding outdoor air pollution data were collected. We are also piloting a spatially-improved version of the Spiroscout in a subset of the homes sampled in winter 2012 (ongoing). Results:Preliminary results show that the Spiroscout accurately captures temporal inhaler use, but often does not record sufficient spatial information, perhaps due to poor satellite reception. Nonetheless, the time-resolved inhaler use data will allow us to examine the preliminary association between multiple indoor and outdoor air pollution exposures (lagged) and short-acting beta agonist use using general linear models. Conclusions:With some improvements, the Spiroscout could offer an immediate and more accurate and reliable means of assessing medication use, compared to existing alternative methods including doselogging devices, questionnaires, or mobile interfaces. This monitoring advancement could lead to important advances in understanding factors responsible for asthma exacerbation.