Questions about air-quality testing in high school [closed]

Question

The Pinelands Regional High School in Ocean County New Jersey was closed for four days last week for air quality concerns after rooftop construction. Yesterday was the students‘ first day back. There have been conflicting reports of health issues, but it generally seems that the first day back is going OK.

There were two rounds of air-quality testing conducted last week. The first found unacceptable levels of multiple chemical compounds, the second, conducted two days later (after being cleaned), found no dangerous levels of any chemical.

Full results document of each test

• Test 1: October 3
• Test 2: October 5.

All of the unacceptable results found in round one (Indicated by red flags):

Sample: Room 164

Chemical | Actual ug/m3 | Times greater | NIOSH Res uh/m3

• Ethelbenzene | 2.7 | 2.45 | 1.1
• 1,2,4-Trimethylbenzene | 15 | 2.05 | 7.3

Sample: Upper level - Media

Chemical | Actual ug/m3 | Times greater | NIOSH Res uh/m3

• Benzene | 8.9 | 24.72 | 0.360
• Ethelbenzene | 37 | 33.64 | 1.1
• Xylene (p,m) | 110 | 1.1 | 100
• 1,2,4-Trimethylbenzene | 180 | 24.86 | 7.3
• Naphthalene | 11 | 132.52 | 0.083

The clean results of round two

Chemical | Actual ug/m3 | NIOSH Res ppm

• Benzene | 8.9 | 0.360
• Ethelbenzene | 37 | 1.1
• Xylene (p,m) | 110 | 100
• 1,2,4-Trimethylbenzene | 180| 7.3
• Naphthalene | 11 | 0.083

This report concludes: "TTI has evaluated the results and can confirm that none of the target compounds exceeded limits for either exposure or notification at both the state and federal levels."

Confusion

There are a number of things I find confusing about this.

• First, the first round of tests analyze specific areas in the school, but the second does not identify any area.
• Both rounds seem to have measured almost exactly the same levels.
• The recommended NIOSH residential levels are measured in ug/m3 in round one testing, but ppm in round two. In round one, for example, the recommended maximum for benzene is 0.360, which according to this tool, translates to 0.00036 ppm. However, on the second test, has a recommended maximum of 0.1 ppm. Also, the same calculator translates benzene’s ug/m3 of 8.9 to 0.0089 ppm, but in the Test two results, it is translated to 0.0028.
• Finally, parents are simply unfamiliar with these chemicals and what the levels imply, and how they affect teenagers. It is hard to fight what you can’t see or smell.

Help understanding and interpreting these results, and especially in giving parents some reassurance if it is warranted, would be appreciated. Thanks.

Answer 1

First off the acceptance levels the first time are way lower then the second time, you should ask why there is a large difference. (I have no clue, it's quite important since the second time those limits are NOT met!)

I found NO acceptance level for the chemicals (long term exposure.) THE most accepted guidelines are usually set by the world health organisation and even they do not dare to set limits since it is difficult see http://www.euro.who.int/en/health-topics/environment-and-health/Housing-and-health/publications/2010/who-guidelines-for-indoor-air-quality-selected-pollutants For common benzene they wrote a small book.

But to put it in perspective, I think that you inhale way more of those chemicals during filling your car. Then staying in the classroom for a week ;) [Citation needed!] Edit: the concentrations are actually all more elevated then the averages mentioned by literature. Can we please have a copy of the raport? Next time it might be better to measure air quality according to the WHO guidelines since we simply do not know what we are looking at.

"First, the first round of tests analyze specific areas in the school, but the second does not identify any area. Both rounds seem to have measured almost exactly the same levels." I agree, this is weird. You should ask where and how this is sampled. But there are regulations for the sampling, let's assume they are professionals and based on previous results this is a worst case measurement.

"The recommended NIOSH residential levels are measured in ug/m3 in round one testing, but ppm in round two. In round one, for example, the recommended maximum for benzene is 0.360, which according to this tool, translates to 0.00036 ppm. However, on the second test, has a recommended maximum of 0.1 ppm. Also, the same calculator translates benzene’s if/m3 of 8.9 to 0.0089 ppm, but in the Test two results, it is translated to 0.0028." PPM is a horrible unit without actual dimensions just like percentages. Are we talking about volumes, weights , molars or a mix? Anyway, just use the ug/m3 since that's what really Is measured. (I you like you can see the right conversions inside the WHO document http://www.euro.who.int/en/health-topics/environment-and-health/Housing-and-health/publications/2010/who-guidelines-for-indoor-air-quality-selected-pollutants but that's only if you like math ;)

"Finally, parents are simply unfamiliar with these chemicals and what the levels imply, and how they affect teenagers. It is hard to fight with you can’t see or smell." I totally agree! But don't underestimate the nose ;) I GUESSE, looking at the numbers there is no extreme dangerous exposure. The second report concludes the the same. The world health organisation does not exactly know what levels are really exceptional dangerous, therefore it's by "law save" as long as there are no observed health problems. But just ask the professionals ;) This is where my field ends, it's up to you to tell the right people the right information and ask the right questions, (you are probably way better at that then I am ;) good luck!!