Rationale and definition:
Rapid urbanization has resulted in increasing urban air pollution in major cities, especially in developing countries. It is estimated that over 1 million premature deaths can be attributed to urban ambient air pollution.1 This has severe economic and health impacts, particularly for young children. We therefore propose that the post-2015 framework include an indicator tracking the mean urban air pollution of particulate matter.
PM10 is the concentration of particles with a diameter equal to or greater than 10 microns (μ), which are usually produced from construction and mechanical activities, while PM2.5 is the concentration of particles with a diameter equal to or greater than 2.5 microns, usually produced from combustion. These smaller particles are actually more damaging as they permeate the lung more deeply. WHO has set guidelines for PM10 at 20 μg/m3 annual mean and 50 μg/m3 24-hour mean and for PM2.5 at 10 μg/m3 annual mean and 25 μg/m3 24-hour mean.2 However, many cities regularly experience concentrations over 10 times higher than these recommendations.
By city and province.
Comments and limitations:
Many countries track the concentration of PM10 (i.e. particles with a diameter equal to or greater than 10 microns) and PM2.5 (diameter equal to or greater than 2.5 microns) for large cities and report this data to WHO. We recommend that both indicators be tracked in all urban agglomerations of greater than [250,000] people. Global statistics agencies should develop a framework for gathering the data. Complementary indicators include population-based measures, such as “percentage of population whose exposure to PM10 and PM2.5 is above certain μg/m3 (i.e. 15) threshold,” which can provide city authorities with important information on how to direct policies to lower the health impact of air pollution.
Preliminary assessment of current data availability by Friends of the Chair:
Primary data source:
Remote sensing (satellite-based measurements are the most comprehensive and cost effective).
Potential lead agency or agencies:
UN-Habitat, UNEP, WHO.