A great paper to read.
EVALUATION OF POTENTIAL CHANGES TO THE
COARSE PARTICULATE MATTER NATIONAL AMBIENT AIR QUALITY STANDARD
This paper shows part of the journey traveled by the EPA, agricultural, industrial and mining parties with regard to Particulate Matter Pollution. Of interest and value for the South African context is the emphasis on reliable data. To make critical decisions on erratic and potentially unrepresentative data is going to cause problems.
Air pollution is important enough err on the cautious or over protective side, but this will only work if all parties see the value in being over protective, or if the protection is funded by a central organisation.
The expense and time spent on monitoring in some cases may have been better spent on dust control and proactive particulate matter prevention.
The paper also highlights the important of natural events that can lead to high Particulate matter levels over a 24 hour period. This is particularly relevant in South Africa where many areas are arid, farmers burn their lands before planting, and mountain fires are common. In the Cape Town the strong winds keep the Particulate Matter levels down, but they build up quickly when there is a week with no strong winds.
http://www.beefusa.org/CMDocs/BeefUSA/Issues/PM%20Final%20PM10%20Report%200711.pdf