Wednesday, February 22, 2012

Interpreting pollution maps for the proposed Cleveland incinerator




CLEVELAND — “To read the maps [78 MB pdf download] is actually easy, but it’s more important to understand how to interpret what they mean to the average neighbor. Each color is a different average daily concentration that will be experienced over the five years they modeled. As you get further away, the concentration gets lower. Purple and dark blue are highest, light pink is lowest. They only modeled the impact to a distance of 2,000 meters, 6,561 feet, or about 1.2 miles away from the stacks. (Not really “well over a mile” as the report says.)

The report states the following:



“The AERMOD [American Meteorological Society/Environmental Protection Agency Regulatory Model] dispersion modeling was performed with the maximum worst case hourly emissions requested in the air permit application. The air quality modeling assumed that all four proposed gasifier lines were simultaneously operating at the maximum operating rate and maximum emission rate for each air pollutant for each hour of the five‐year period.”

Put another way, the maps show the average additional pollution that these neighborhoods will experience every day for five years if the plant runs at max capacity and all things go as planned.

First, some background. They are using the National Ambient Air Quality Standards. These standards are not for a single source. They are what is allowed for the outdoor air. In other words, if the air currently has 50 percent of that pollutant, a new pollution source adds to it. In order to determine impact of a single source such as the incinerator, one needs to know the average and max concentrations already present. So don’t be fooled when someone quotes that the plant will only emit a low percentage of the National Ambient Air Quality Standards. They are allowing that plant to add to our air. That puts a burden not only on health, but on the entire region, because the region must stay below the standards. According to the U.S. EPA
“The Clean Air Act, which was last amended in 1990, requires [the U.S.] EPA to set National Ambient Air Quality Standards for pollutants considered harmful to public health and the environment. The Clean Air Act identifies two types of national ambient air quality standards. Primary standards provide public health protection, including protecting the health of ‘sensitive’ populations such as asthmatics, children, and the elderly. Secondary standards provide public welfare protection, including protection against decreased visibility and damage to animals, crops, vegetation, and buildings.”

The U.S. EPA has set National Ambient Air Quality Standards for six principal pollutants, which are called “criteria” pollutants. For example, from the modeling maps, let’s take a look at one of the pollutants, SO2, the rotten egg smell, a known toxin, and is a primary cause of acid rain (mix SO2 with water, get sulfuric acid). It may be important to note the model reports SO2 in concentrations of micrograms per cubic meter of air. The standard uses parts-per-billion or parts-per-million for SO2.

According to the model, the average per hour emission of SO2 for five years can be anywhere from 10% of the max allowable up to more than 40. The maps do not provide the complete upper range of the concentration for any area, only a color area showing the range of that average. In other words, any one of these spots may experience the max predicted concentration at any given time (unpredictable). For SO2, that max is predicted to be 23% of the allowable. So there is a very close neighborhood shown in purple/dark blue that will always experience a range of greater than 20% of the allowable for SO2. The next area, blue, will experience, always, a range of 30-40% of the max allowable; then light blue, a 20-30%; the pinks are less than 20%.

So when they say the plant won’t emit odors, ask them how sensitive they are to that rotten egg smell. We often get it from other plants around town, depending on their operations. It is always unwanted.

For lead, the max range is greater than 13% of the allowable. This is in addition to the exposure currently experienced by an already poisoned and at risk population. Lead poisoning in children has long been a problem in Cleveland, with huge efforts by the public health sector to reduce the incidence. Lead poisoning is thought by some to be one of our region’s worst public health tragedies, annually impacting tens of thousands of our children over several decades if not nearly a century of exposure.

More quotes from the U.S. EPA, not the Ohio EPA, which is a bit different, both in operations, quality, experience, and legality –

Sulfur dioxide (SO2) is one of a group of highly reactive gasses known as ‘oxides of sulfur.’ The largest sources of SO2 emissions are from fossil fuel combustion at power plants (73%) and other industrial facilities (20%). Smaller sources of SO2 emissions include industrial processes such as extracting metal from ore, and the burning of high sulfur containing fuels by locomotives, large ships, and non-road equipment. SO2 is linked with a number of adverse effects on the respiratory system.

“EPA first set standards for SO2 in 1971. EPA set a 24-hour primary standard at 140 parts-per-billion and an annual average standard at 30 parts-per-billion (to protect health). EPA also set a 3-hour average secondary standard at 500 parts-per-billion (to protect the public welfare). In the last review, EPA also considered, but did not set, a 5-minute NAAQS to protect asthmatics at elevated ventilation rates from bronchoconstriction and respiratory symptoms associated with 5-10 minute peaks of SO2. [This means that high but short concentrations that produce acute, dangerous reactions is a small sector of the population are not considered].
“Current scientific evidence links short-term exposures to SO2, ranging from 5 minutes to 24 hours, with an array of adverse respiratory effects including bronchoconstriction and increased asthma symptoms. These effects are particularly important for asthmatics at elevated ventilation rates (e.g., while exercising or playing.)
Studies also show a connection between short-term exposure and increased visits to emergency departments and hospital admissions for respiratory illnesses, particularly in at-risk populations including children, the elderly, and asthmatics. EPA’s National Ambient Air Quality Standard for SO2 is designed to protect against exposure to the entire group of sulfur oxides (SOx). SO2 is the component of greatest concern and is used as the indicator for the larger group of gaseous sulfur oxides (SOx). Other gaseous sulfur oxides (e.g., SO3) are found in the atmosphere at concentrations much lower than SO2. Emissions that lead to high concentrations of SO2 generally also lead to the formation of other SOx. Control measures that reduce SO2 can generally be expected to reduce people’s exposures to all gaseous SOx. This may have the important co-benefit of reducing the formation of fine sulfate particles, which pose significant public health threats.

“SOx can react with other compounds in the atmosphere to form small particles. These particles penetrate deeply into sensitive parts of the lungs and can cause or worsen respiratory disease, such as emphysema and bronchitis, and can aggravate existing heart disease, leading to increased hospital admissions and premature death. EPA’s NAAQS for particulate matter (PM) are designed to provide protection against these health effects.”

— Scott Armour, Armour Applied Science, LLC, Director, Cleveland Chapter of the Indoor Air Quality Association

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