Scales of Green

EPA’s Air Quality Index (AQI)

Dec 05

Posted: under Green Places.


After four posts about scales measuring the environmental performance of automobiles, auto companies, city transportation policies, and even our personal driving skills, we might think that if we do well on each of these measures, our environment should be doing okay.  But how would we know?  We also need measures of environmental quality — the current state of our environment — to assess whether our actions are making a difference; indeed, these are the “Scales of Green” that ultimately matter the most.

One measure that may be a good start is the Air Quality Index (AQI), which the federal government requires all metropolitan areas with populations greater than 350,000 to calculate and distribute to local media outlets.  The scale is from 0 to 500, with five levels and colors of increasing health concern, and highlights pollutant levels that may be particularly hazardous for at-risk groups (e.g. people with heart conditions, asthma, etc.).

Transparency: Air*

EPA’s website provides in-depth descriptions of the AQI and how it is calculated.  A particularly detailed document oriented towards state and local air quality monitoring agencies provides the methods, equations, and tables that should be used to generate the AQI.  The site discusses both what is measured and is not measured, and the limitations of the metric.

Governance: Republic

The AQI is calculated by government agencies based on data from approved air monitoring stations across the country. The EPA provides overall guidance and regulation of the process, while state and local agencies implement it.

Coverage: Hedgehog

While Air Quality Indexes can be calculated for as many as five air pollutants, it does not cover any of the 188 air toxics covered by the Clean Air Act nor any water and ground pollutants.  And often only ozone and particulate matter AQIs are calculated and distributed (if the others are generally shown to be below 50).  Therefore it is a relatively narrow measure of environmental performance, but it is also one of the most precise environmental quality measures available.

This Scale’s “Greenness:”

According to the EPA’s AirNow site, the AQI “tells you how clean or polluted your air is, and what associated health effects might be a concern for you.”  But let’s remember a few important points about this scale:

1. The AQI measures concentrations of five primary pollutants, not toxic pollutants that are more likely to result in longer-term, chronic health outcomes like cancer. An EPA study showed that in some areas these chronic risks may indeed be significant (click here for more info).

2. The AQI focuses on hourly and daily pollutant levels, not long-term trends. The EPA’s National Ambient Air Quality Standards (NAAQS) are more relevant to evaluating our national air quality progress, and EPA’s most recent Trends Report shows that while air quality for the five primary pollutants discussed above has improved over the last 30 years, there are still 158.5 million Americans (more than half) who live in counties with air quality concentrations above the NAAQS.

3. The AQI is focused on human health effects of the air pollutants it measures, not their effects on visibility, either locally or in National Parks, or their effects on vegegation, crops, buildings, and wildlife. Such effects can be significant — see this site on crop damage from ozone as an example.  So while a low AQI may be good for your personal health, it may not necessarily mean the environment is not still being affected.

* For an explanation of the Transparency, Governance, and Coverage “ratings” above, please click here.

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Our Green Home

Oct 14

Posted: under Green Places.

When a house is tottering to its fall,
The strain lies heaviest on the weakest part,
One tiny crack throughout the structure spreads,
And its own weight soon brings it toppling down.

Ovid (43 B.C.–A.D. 17/18), Roman poet. Tristia, 2. 83-86.

We expect our homes to provide us with a few basic but key services — shelter, running water, ventilation, heat, air conditioning, etc.  If we’re lucky, our homes may even have a garden that provides us with food as well.  They also provide us with more intangible and sentimental benefits — as Phillip Moffitt states, “A house is a home when it shelters the body and comforts the soul.”  This may be why Martha Stewart makes a similar differentiation: “What we’ve been trying to do is keep our homes — we’re trying to make our houses homes in the first place and then once they are homes, how to take care of them.”

Our planet is in many ways both our house and our home.  It provides both tangible benefits to us, including the air we breathe, the food we eat, and the water we drink, as well as intangible ones, from the awesomeness of the highest Himalayas to the mysteries of the ocean’s darkest depths.  All of this, for free and with no interest, amazingly –even better than a sub-prime loan, and without the following financial implosion.  Indeed, a study published in Nature 10 years ago estimated the total value of these services to be $33 trillion a year — nearly double the value of global GNP at the time (Costanza et al 1997).

Yet despite its incredible value to us, scientists around the world have been claiming for years that humanity is undermining and even destroying the systems that provide us with these natural benefits. A recent EU-commissioned study calculated the annual cost of forest loss around the world to be between $2 trillion and $5 trillion, which is more than double this year’s $1-$1.5 trillion losses in the financial sector.  Armed with such evidence that our great green house of Nature is, in the words of Ovid, “tottering to its fall,” they point to cracks in its foundation, in its frames and walls, in its pipes and wires.  But where is the heaviest strain, the “weakest part?”  What is causing the toppling, if indeed it is happening?  Where and how should we focus our energies to keep our house and home standing?

Scientists, engineers, and politicians all have different answers to these questions.  The climatologists argue the climate is our greatest environmental challenge, biologists claim species extinction is our most urgent and irreversible ecological issue, hydrologists believe water quantity and quality is the greatest environmental threat to human health.  Skeptics disagree with all of them, citing evidence of the resiliency and adaptivity of both the Earth and human beings over time.  And then there are disagreements within each of these groups as well, about which places, which species, which cycles are most at risk.  What is an average but concerned citizen and consumer to do with all this discord?

This section of the website will explore some of these questions about the state of our planet — who is measuring it and how, and what they are finding and saying.  An increasing number of relatively legitimate and robust efforts to assess “environmental quality” are underway, at a range of ecological scales.  While they still leave much to be desired, they are critical efforts, as ultimately all other measures of environmental performance — of products, companies, governments, and individuals — depends on an understanding of their environmental impact.  Such an understanding requires a baseline and snapshots of  ecological health over time, so we can assess the effects of environmental efforts at each different scale of human activity.

So how green is our home?  As green as it’s inhabitants, and as green as its inhabitants allow it to be.  We’ll see just how green that is in the posts to come…

Photo credit:…/eco-house-from-willa-nordic/.

Ovid quote:

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