Mapping the visibility of smokers across a large capital city.

backgroundSmoking visibility may affect smoking norms with implications for tobacco initiation, particularly amongst youths. Understanding how smoking is distributed across urban environments would contribute to the design and implementation of tobacco control policies. Our objective is to estimate the visibility of smokers in a large urban area using a novel GIS-based methodological approach.

methodsWe used systematic social observation to gather information about the presence of smokers in the environment within a representative sample of census tracts in Madrid city in 2016. We designed a GIS-based methodology to estimate the visibility of smokers throughout the whole city using the data collected in the fieldwork. Last, we validated our results in a sample of 40 locations distributed across the city through direct observation.

resultsWe mapped estimates of smokers' visibility across the entire city. The visibility was higher in the central districts and in streets with a high density of hospitality venues, public transportation stops, and retail shops. Peripheral districts, with larger green areas and residential or industrial land uses, showed lower visibility of smokers. Validation analyses found high agreement between the estimated and observed values of smokers' visibility (R = 0.845, p=<0.001). DISCUSSION: GIS-based methods enable the development of novel tools to study the distribution of smokers and their visibility in urban environments. We found differences in the visibility by population density and leisure, retail shops and business activities. The findings can support the development of policies to protect people from smoking.