ENV2: Ambient concentrations of air pollutants in urban areas Brief Definition Ambient concentrations of air pollutants such as
ozone, carbon monoxide, particulate matter
(PM10, PM2.5, total suspended particulate [TSP],
black smoke), sulphur dioxide, nitrogen dioxide,
benzene and lead
Units Micro- or milligrams per cubic metre (
μg/m
3
or
mg/m
3
), as appropriate
Alternative Definitions None
Agenda 21 Chapter 9: Protection of the atmosphere
POLICY RELEVANCE (a) Purpose: This indicator provides a measure of the state of the environment in
terms of air quality, which can be a health concern in urban areas. It also provides an
indirect measure of the population exposure relevant to impacts on human health and
vegetation. (b) Relevance to Sustainable Development: An increasing percentage of the world’s
population lives in urban areas. High population density and the concentration of
industry and traffic exert great pressures on local environments. Air pollution from
energy use in households, industry, power stations and transportation (motor vehicles)
is often a major problem. As a result, the greatest potential for human exposure to
ambient air pollution and subsequent health problems occurs in urban areas.
Improving air quality is a significant aspect of promoting sustainable human
settlements. This indicator may be used to monitor trends in air pollution as a basis for
prioritizing policy actions; to map levels of air pollution in order to identify hotspots
or areas in need of special attention; to help assess the number of people exposed to
excessive levels of air pollution; to monitor levels of compliance with air quality
standards; to assess the effects of air quality policies; and to help investigate
associations between air pollution and health effects.
