What Is The Daily Air Quality Index?

Ever since the early part of the industrial revolution, air quality has been a concern both indoors and outdoors, and some of the earliest occupational health and safety legislation was particularly concerned about ventilation in certain workplaces.

Factories have had to be ventilated, cleaned and well lit since 1802 and rudimentary building air quality testing has been in force since the 1830s, with more advanced technology, scientific understanding and methodology coming to the fore in the centuries since.

At present, outdoor air quality is measured by the Daily Air Quality Index and has been since July 2011, when the Committee on the Medical Effects of Air Pollutants (COMEAP) published a report on the importance of clean air, and a simple ten-point scale for determining levels of air pollution.

This scale is determined by the concentration of five particular pollutants:

· Nitrogen Dioxide, often emitted by diesel cars,

· Sulphur Dioxide,

· Ozone,

· Particles smaller than 2.5 nanometres (PM2.5),

· Particles smaller than 10 nanometres (PM10).

After the air pollution value is calculated from the concentrations of these pollutants, this value is

then assigned one of four air pollution bands, from Low (1-3), Moderate (4-6), High (7-9) and Very High (10).

This then corresponds to two different sets of advice, with one made for the general population and one for people who are deemed to be ‘at-risk’ of heart or lung problems caused by excessive pollution.

The DAQI is divided into general areas, and so the general air quality forecast typically does not factor in the pollution that is more localised to congested roads or in urban centres.

Lower air pollution has been linked to improvements in several organ functions, including the lungs and the kidneys, due to the lack of long-term exposure to high PM2.5 levels which can affect kidney function.