In the study, air quality was measured using the air-pollution
index, which is calculated based on daily readings of three air pollutants, namely sulfur dioxide, nitrogen dioxide and PM smaller than 10 um (PM10).
Effect of air-pollution
control on death rates in Dublin, Ireland: an intervention study.
levels have dropped dramatically in recent decades, and are now at the lowest level ever recorded.
In exchange for prospective relief from new source review, the power companies were prepared to accelerate their air-pollution
reductions through a market-based permit system.
* In a "Serious" air-pollution
region, you're a major" polluter if you emit only 50 TPY, and you have nine years to clean up your act."