Modelling of nitrogen dioxide (NO₂) and fine particulate matter (PM₁₀) air pollution in the metropolitan areas of Barcelona and Bilbao, Spain

Abstract

SUMMARYEcological studies in epidemiology present some limitations on assessing the exposure of environmental factors. The main objective of this study was to describe a statistical methodology that could help on more accurately assessing the relationship between air pollution and health responses at very small spatial scale.In particular, we modelled the spatial distribution of nitrogen dioxide (NO 2 ) and of particles with a diameter of less than 10 mm in two study areas, the metropolitan areas of Barcelona (MABa) and Bilbao (MABi). The areas chosen for this project can be distinguished for having similar population density and urban surface, as well as high road traffic intensity. The geographical variability of the pollutants could differ greatly due to very different orographic and climatic conditions. Three contributions of this study could be mentioned. First of all, the spatial distribution of the values of each air pollutant was spread over the entire study region on a small area basis, that is census track in our case. Secondly, a stochastic interpolation method, kriging, was used. Thirdly, instead of estimating the average value of the pollutant at the centroid of the area for the entire study period, the value was estimated for each and every day of the corresponding period.As regards the main results, in both areas it can be observed that those census tracks with a greater concentration of pollutants are those that were estimated more accurately. This suggests the existence of a persistent emission source in those tracks, very probably those roads with greater road traffic intensity.

Statistical Modeling Approaches for PM10 Prediction in Urban Areas; A Review of 21st-Century Studies

“…Kriging and IDW were employed for spatial prediction of PM 10 in Istanbul, Turkey [91] and Phoenix, Arizona, USA [92]. In total, Kriging has been applied more often in urban areas (e.g., metropolitan areas of Barcelona and Bilbao, Spain [93], an urban scale in Europa [94], Phoenix metropolitan region, Arizona [95] and Mumbai, India [96]), than have other typical deterministic interpolation techniques.…”

Assessment of Areal Average Air Quality Level over Irregular Areas: a Case Study of PM10 Exposure Estimation in Taipei (Taiwan)

“…administrative division. Among them, the most common approximation is to use the air pollution estimation at the centroid to represent the average pollution level of the entire area of concern (Chen and Schwartz, 2008;Chen and Schwartz, 2009;Lertxundi-Manterola and Saez, 2009;Maheswaran and Elliott, 2003;Miller et al, 2007). The impact of the size and shape of geographical units to the estimation results is seldom considered (Goovaerts, 2008).…”

“…where , (Chen and Schwartz, 2009;Lertxundi-Manterola and Saez, 2009;Maheswaran and Elliott, 2003). In addition, to assure the comparison is performed at the same basis, the nonstationarity of PM10 process in space and time is removed by locally weighted smoothing regression method (LOESS) (Cleveland, 1979;Cleveland and Devlin, 1988) in advance to the applications of the spatial-time interpolation techniques.…”

“…Most spatial interpolators are originally developed for the estimations with geographical support of estimation and observation locations at point scale. As a result, most studies of exposure assessment apply spatial techniques for point estimation at the centroid of the geographical unit of interest to characterize its average air pollution level (Chen and Schwartz, 2008;Chen and Schwartz, 2009;Lertxundi-Manterola and Saez, 2009;Maheswaran and Elliott, 2003;Miller et al, 2007). The inconsistency of geographical support between the exposure estimations and aggregated health dataset can potentially distort the results of their associated epidemiological studies (Young et al, 2009;Young et al, 2008).…”

Impact of Urbanization on Local Air Quality: Differences in Urban and Rural Areas of Balikesir, Turkey

“…Meteorological factors, topography, and urban settlement are significant factors influencing dispersion, accumulation, and chemical transformation of air pollutants. It is well known that air pollution in an urban atmosphere causes adverse effects on human health and the environment . There is abundant evidence linking air pollution with aggravate airway pathology, respiratory symptoms, reduced lung function, hospital admissions, and increased mortality .…”