More on Smog - technical

My associate, Bonnie Quezada, and I spent some time yesterday morning doing some basic research on air quality. We wanted to share some of our results with others who may be interested. Here is a version of the email we sent to friends and associates (I wasn't able to keep the charts, so you will have to look at the links). I know this is messy, but we are in a hurry to leave the country!

Overview
Terminology:

• Several abbreviations are used that can be confusing – Here are some of the terms used and what we believe (based on our research today) they mean:
• AQI = Air Quality Index (calidad del aire): this number arises from an analysis that looks at both particulate matter and ozone content; here is a brief explanation.
• PM10 and PM2.5- Particulate Matter – of the inhalable variety has a range of sizes. PM10 refers to the largest that are inhalable (10 microns across) and PM2.5 refers to the most dangerous PM as it is only 2.5 microns wide (very small). The annual geometric mean of particulate matter is called the ug/m3.
• O3 and PPB – O3 refers to ground level ozone and PPB refers to the annual mean of ozone.
  Advisories and Warnings using AQI Different Indices are difficult to compare as they refer to different standards. The U.S. AQI is a composite index using ozone, particulate matter and many other pollutants. The EPA has a good explanation of their AQI composite index at http://airnow.gov/index.cfm?action=static.aqi. This page also shows the chart used by the EPA.

In Chile

How do you find out the current air quality according to Chilean authorities? You can see their reporting here. If you are interested in the history of smog in Santiago, go to statistics on air quality. Their Chart is based on a rating figure called the ICAP, explained below. This index seems to be based only on particulate matter. Chilean authorities gauge the ozone levels separately. The Chilean Advisory Chart looks like this.

Their definitions used in defining their ICAP (Indice de Calidad del Aire Particulado):
ICAP: Indice de Calidad del Aire por Partículas. Es un indicador creado por el artículo 1, letra g, del Decreto Supremo 59, de 1998, del Ministerio Secretaria General de la Presidencia y la Resolución 369, de 1988 del Ministerio de Salud, basado en la cantidad de partículas respirables (PM10), medidas en microgramos, presentes en un metro cúbico. Derivado de la función lineal segmentada definida por los puntos 0 ug/m3 = 0 ICAP, 150 ug/m3 = 100 ICAP y 330 ug/m3 = 500 ICAP.

As a basis for real comparison, the EPA also has a chart for quantities of just Particulate Matter: It seems that the U.S. EPA has a much higher standard based on this chart. The U.S. standards do not even reach 300 (Chilean Pre-emergency), nor 500 (Chilean emergency levels).

Other Good Sources of Information:

Ministry of the Environment (Ontario, Canada)
American Lung Association has some very clear fact sheets:

• Fact Sheet on Ozone
• Fact Sheet on Particulate Matter Pollution
• Overview of Information on Outdoor Air Quality

U.S. EPA

• Air quality guide for Bangkok levels are based on PM and are well below Santiago, currently.
• China -- Beijing is currently at 194 based on particulate matter.
• Mexico City – skies are currently much clearer than here in Santiago.
• The Indian air quality index and standards.