The American Lung Association is scheduled to release its annual State of the Air report on April 28, 2009. The report can provide a useful hook for reporting on air quality in your community. But your audience will be better served if you go well beyond the sound-bite information that is emphasized in the report.
In previous years, the methodology used by ALA emphasized just a few measures of ozone and fine particulates, both of which are generally considered important pollutants. The final grade that ALA assigns to the counties with available data emphasizes exceedances of EPA standards, and counties that receive a poor grade clearly have air quality that poses some degree of risk to residents.
However, counties that have a relatively good grade, per ALA, may also have air that poses a significant risk to its residents. That is true for a number of reasons.
The EPA standard for ozone, tightened to 75 ppb March 12, 2008, has come under sharp criticism from both within and outside the agency for the lack of protection it provides people. Many US scientists say a more protective standard would be 60-70 ppb. The World Health Organization, which is less constrained by political and economic considerations when issuing its voluntary guidelines, says even that is too high, recommending 51 ppb. A number of scientists have found that concentrations as low as 10-25 ppb are harmful to some people.
In addition to concerns about the official standard, there are nuances in how EPA measures ozone and calculates violations of its standard that distort the validity of what the public sees. For some insight on those issues, as well as other ozone realities, see:
- "Ozone Nation: EPA Standard Panned by the People," Environmental Health Perspectives, July 2008, by Bob Weinhold.
Another valuable resource when reporting on ozone is the hourly forecast site operated by EPA and NOAA.
This data helps fill in the major gaps between air monitors. It also helps dispel some of the myths associated with ozone, such as that it is relatively high only in the summer. For example, look at the western US on almost any day or night, and you'll see areas that are near or above the WHO standard, even in the middle of the night in the middle of winter. Incidentally, the agencies have not provided an archive of previous data, or a cumulative assessment for a year, so for now you'll need to track this site regularly to get a feel for patterns.
If you're interested in global ozone forecasts, see:
- Near Real-Time Fields (produced by the European Centre for Medium-Range Weather Forecasts); site includes data on carbon monoxide, which is a useful surrogate for a wide range of pollutants.
The emphasis of ALA and EPA on exceedances of a maximum standard doesn't address long-term exposures. As just one example, Colorado Springs, CO (in El Paso Co.), received a "B" in last year's ALA report, suggesting relatively good air quality. But the concentration AVERAGED 54.4 ppb for 2008. Since the WHO guideline of 51 ppb is for a one-time occurrence in a year (and since a number of scientists say the health threshold is more likely 10-25 ppb), that means that residents of El Paso Co. (and the great majority of US counties, for that matter) are being exposed to air that is far less healthy than many scientists consider safe.
The EPA standard for fine particulates, revised in 2006, has also come under sharp criticism from both within and outside the agency. There is substantial argument over whether the annual standard should be 15 ug/m3, as now exists, or a little lower at 13-14 ug/m3, as many scientists and health and environmental advocates recommend. The difference may seem small, but the lower standard would have put a large number of additional counties out of compliance, potentially costing them significant money.
As with ozone, though, a growing body of evidence is showing that even the standard being proposed by EPA critics may be far too high to be truly protective, since almost no concentration can be considered safe. For just one example of such a study, see:
- "The Concentration-Response Relation Between PM(2.5) and Daily Deaths," Environmental Health Perspectives, October 2002.
But as is clear with the current standards, political and economic realities invariably drive a standard much higher than something near zero. In addition to informing your audience about the combined political, economic, and scientific forces that shape the determination of a health standard, you can cover angles of the fine particulates issue that parallel those raised with ozone, such as how and where it is measured, whether differences in chemical composition and physical properties of fine particulates are accounted for, whether the standard provides adequate long-term health protection, and whether people in areas between monitors are being adequately protected.
Regarding the health risks posed by ozone and fine particulates, ALA attempts to quantify the number of people at risk. However, as noted in its methodology, the numbers are based on calculations derived from assumptions applied uniformly across the country. The final results are not real numbers that take into account the unique characteristics of each county.
Another limitation of the ALA report is that it can induce some reporters to conclude that some or all of the counties of interest to their audience have good air quality because the counties aren't addressed in the report. The omission of a county generally means simply that there isn't an ozone or fine particulate monitor in the county, not that air quality is healthy.
Another reporting mistake that can be made is taking the ALA letter grades at face value. For instance, many of the suburban counties around Denver, CO, have worse grades for ozone than Denver. But that's due in large part to a quirk of atmospheric chemistry; all the other airborne chemicals in urban Denver tend to break down ozone, leading to a false impression of cleaner air if ozone is the only factor considered.
Which leads to a much greater limitation of the ALA report. Ozone and fine particulates, though widely considered important pollutants, are just two of the thousands of pollutants that can threaten health. A far more accurate assessment of overall air quality needs to take into account the occurrence of these other pollutants. There is no accepted formula for a comprehensive look at all pollutants, but you can better serve your audience by reporting during the course of the year on a significant number of the pollutants that are tracked. When referring to the narrow findings of the ALA report, this knowledge of the bigger picture of air quality will induce you to not use blanket statements such as "the dirtiest city in the country" or "one of America's cleanest cities."
A few starting points for reporting on other pollutants that have been assigned to various categories include: