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Excerpted from Galena-Park-Monitoring-Report-FINAL.pdf

Continued from http://publiclab.org/wiki/edit/galena-park-monitoring-report-iv

V. Total PM2.5 Results

The averages of all samples as well as the means at each monitoring site exceeded the Environmental Protection Agency (EPA) and World Health Organization (WHO) annual fine particulate matter standards. Fine particulate matter pollution may present a health risk to the residents of Galena Park.

A. PM2.5 Samples Exceed EPA and WHO Health Standards

Thirty-one samples were collected between November 2012 and September 2013, with one early sample collected May 2013. Samples were analyzed for PM 2.5 by gravimetric analysis.

Dr. Chernaik offers this explanation of the health effects of PM2.5 and of the EPA and WHO standards:

There is a robust association between health effects and ambient levels of particulate matter. Very small (fine) particles exert disproportionately more health effects than do larger particles. According to the U.S. EPA:

“Particles less than 10 micrometers in diameter (PM10) pose a health concern because they can be inhaled into and accumulate in the respiratory system. Particles less than 2.5 micrometers in diameter (PM2.5) are referred to as "fine" particles and are believed to pose the largest health risks. Because of their small size (less than one-seventh the average width of a human hair), fine particles can lodge deeply into the lungs.

“Health studies have shown a significant association between exposure to fine particles and premature mortality. Other important effects include aggravation of respiratory and cardiovascular disease (as indicated by increased hospital admissions, emergency room visits, absences from school or work, and restricted activity days), lung disease, decreased lung function, asthma attacks, and certain cardiovascular problems such as heart attacks and cardiac arrhythmia. Individuals particularly sensitive to fine particle exposure include older adults, people with heart and lung disease, and children.”25

Both the U.S. EPA26 and the WHO have adopted short-term (24-hour) and long-term (annual average) standards for exposure to fine particulate matter in order to prevent both acute and chronic effects of exposure to particulates, respectively. 27

The EPA and WHO standards are:

Table 5: PM2.5 Standards

Standard amount
EPA 24-hour standard 35.0 μg/m³
WHO 24-hour standard 25.0 μg/m³
EPA annual standard 12.0 μg/m³
WHO annual standard 10.0 μg/m³

The following table lists all PM2.5 results and compares them to the relevant standards above:

Table_6__PM2.5_Pollution_Results.png

Two individual samples exceeded the WHO’s 24-hour standard. The average of two duplicate samples also exceeds this standard, but it should be noted that the average of 27.6 μg/m³ combines two widely different samples of 19.0 μg/m³ and 36.2 μg/m³. The duplicate sample measuring 36.2 μg/m³ exceeds the EPA’s 24-hour standard, but again, this result was not confirmed by the collocated duplicate sample.

The average of all twenty-nine samples collected throughout the year, 15.2 μg/m³, far exceeds the EPA’s primary annual National Ambient Air Quality Standard of 12.0 μg/m³.28 This raises a serious question whether the health of the people of Galena Park is at risk due to high ambient air levels of fine particle pollution.29 Significantly, the highest single site on average was the Early Head Start center, which is a facility used by low income families, infants and toddlers, and pregnant women. According to the EPA, children are among those most likely to be affected by exposure to particle pollution.30

Dr. Chernaik offered narrative interpretations of the results throughout the project. Portions of these narratives are excerpted below:

What is new about the [data] is that I think we have enough data points for the consistently sampled locations to say something meaningful about the long-term average PM2.5 and EC levels at these locations, and what differences in the long-term averages at the location may be telling us about pollution sources. []

I would conclude that the site ‘Early Head Start,’ with an average PM2.5 level of 16.7 μg/m3 (n=6) and an average EC level of 0.78 μg/m3 (n=5) is more impacted by particulate matter and diesel emissions than ‘Community Resource Center,’ with an average PM2.5 level of 11.7 μg/m3 (n=5) and an average EC level of 0.53 μg/m3 (n=5). Port activities would be a likely explanation for these differences in pollutant levels, considering the relative close proximity of Early Head Start (1908 2nd Street) to the port area compared to the Community Resource Center (1721 16th Street).31

Dr. Chernaik also provided the following analysis of possible pollution sources:

One doesn't need to have information about wind speed and direction to interpret the health significance of the pollutant levels; the wind speed and direction data is mostly to answer the question of what sources are responsible for elevated levels.

For example, in the latest dataset, there is a very high EC level (diesel emissions) - 2.046 μg/m³, one of the highest I've seen - at Galena Park police station for the sample collected Sept 24-25. The Field Data Sheet for this filter (GP29) shows fairly light winds coming from the N-NNE. So, to answer the question of what source(s) might have been responsible for this very high EC level, then I would rely on local knowledge of the area about locations where there is likely to be a lot of heavy vehicle (bus & truck & locomotive) traffic or use of stationary diesel engines.

I have not been to Galena Park, but looking at Google Earth, most of the area directly to the N-NNE of the police station looks like a residential area - an unlikely source of EC (diesel) emissions. Most of the locations I would expect to be sources of diesel emissions are south of the police station (e.g. the rail lines and the container load/unloading port facility). Since we know that winds were very light on Sept 24-25, and that light winds are usually variable winds, then I would recommend fine tuning the analysis by seeing how winds fluctuated that day.

Most of the sample was collected on the 25th (the end time was 5:00) and on the 25th, according to weather underground, there were frequent light winds from the SW: http://www.wunderground.com/history/airport/KHOU/2013/9/25/DailyHistory.html ...which is exactly what you would expect to see if the rail lines and the container load/unloading port facility were the sources of the high EC level in this sample.32

C. AAH/GCM Measurements are Consistently Higher than TCEQ’s, but the Difference is not Statistically Significant

Clinton_Drive_regulatory_monitoring_site.png

The Campos Report compares AAH/GCM monitor values to corresponding daily values at the Clinton Drive monitor.33 The measurements were shown to be highly correlated. Although AAH/GCM values were frequently higher than those at the Clinton Drive monitor, the difference was not statistically significant. The conclusions that can be drawn from this are limited. As explained by Ms. Campos:

While this analysis did not find a statistically significant difference between concentrations measured at AAH locations compared with TCEQ locations, care should be taken in drawing a decisive conclusion based on these analyses because AAH and TCEQ use different sampling and analysis methods. Differences introduced by using different sampling and analysis techniques should be better understood possibly through co-location of an AAH monitor at the Clinton Drive location.34

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