A case study of air quality above an urban roof top vegetable farm. (January 2016)

• Record Type: Journal Article
• Authors: Tong, Zheming; Whitlow, Thomas H.; Landers, Andrew; Flanner, Benjamin
• Is Part Of: Environmental pollution. Volume 208:Part A(2016)
• Page Start: 256
• Page End: 260
• Publication Date: 2016-01
• Subjects: Urban farming -- Intensive green roof -- PM2.5 gradients -- Atmospheric stability -- Dry deposition; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2015.07.006
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: The effect of elevation and rooftop configuration on local air quality was investigated at the Brooklyn Grange rooftop farm during a short-term observational campaign. Using multiple particle counters and sonic anemometers deployed along vertical gradients, we found that PM2.5 concentration decayed with height above the street. Samples adjacent to the street had the highest average PM2.5 concentration and frequent stochastic spikes above background. Rooftop observations 26 m above ground showed 7–33% reductions in average PM2.5 concentration compared with the curbside and had far fewer spikes. A relationship between the vertical extinction rate of PM2.5 and atmospheric stability was found whereby less unstable atmosphere and greater wind shear led to greater PM2.5 extinction due to damped vertical motion of air. Highlights: PM2.5 concentrations on a rooftop farm were 7–33% lower than at ground level. Rooftop plantings will remove less pollution due to the less steep concentration gradient. Vegetables are exposed to less vehicular pollution on roofs than that at ground level. Abstract : PM2.5 concentrations on a rooftop farm were 7–33% below those at ground level, and the vertical extinction rate of PM2.5 varied with the atmospheric stability, and a perimeter wall was the dominant factor governing rooftop boundary layer thickness.