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. Author manuscript; available in PMC: 2017 Aug 13.
Published in final edited form as: Lancet. 2016 May 24;388(10045):696–704. doi: 10.1016/S0140-6736(16)00378-0

Figure 1. Long-term outdoor air pollutant concentrations by area.

Figure 1

Pollutant concentrations are averaged over the time between the first and last CT scan, rounded to the nearest full year. Boxes cover the 25–75th percentile (IQR) with a centre line for the median concentration. Whiskers extend to the highest observation within 3 IQR of the box, with more extreme observations shown as points. Black carbon was measured by light absorption coeff cient, where 0·5 × 10−5 m−1 was approximately equivalent to 0·5 μg/m3 of elemental carbon. PM2·5=fine particulate matter less than 2·5 μm in diameter. NOX=nitrogen oxides. NO2=nitrogen dioxide. ppb=parts per billion.