How will you take care of the following indoor air quality problems?

#1. A family had their home tested for radon with a track-etch detector. The three month average concentration was 15 pCi/L on the first-floor level and 30 pCi/L in the basement. The basement was completely finished and underlain with a good system of drain tiles and fill. The drain emptied to a sump. How will you take care of this indoor air quality problem?

#2. Go to: and find any three radon mitigation specialists in the state of Ohio.

#3. Briefly explain Sub slab depressurization (SSD) and drain title depressurization (DTD).

#4. The radon concentration values for the houses located in the two zip codes were given in the Table below. Calculate arithmetic mean (AM), geometric mean (GM), standard deviation (SD) and coefficient of variation (CV) for each zip code.

Zip code House No. Radon Concentration (pCi/l)
44141 1 6.0
2 6.4
3 30.8
4 4.5
5 7.4
6 3.3
7 1.3
8 4.2
9 4.1
10 2.8
43016 1 5.1
2 12.4
3 4.5
4 1.5
5 19.3
6 4.2
7 3.8
8 3.4
9 9.8
10 3.0

#5.  Calculate standard mean error for each year for the values reported in the Table below

Type of Mitigation System Number of Records Standard Deviation
2005 2006 2007 2008 2009 2005 2006 2007 2008 2009
SSD 1682 1745 1856 2649 2595 13.69 13.66 13.52 13.65 29.04
SSD/SMD 218 436 327 576 342 10.65 10.79 9.53 10.72 22.96

#6.  Immediately after the installation of new carpeting, a family was plagued by a variety of upper respiratory symptoms. On investigation, there did not appear to be any other building -related circumstance which could have accounted for the problem. No new underlayment material was placed under the carpeting.  How will you take care of this indoor air quality problem?   

#7. An old two-story storage building was converted to an office space. A new air-conditioning system was installed before the opening of building.  Employees complained of headaches and lassitude after 11.00 AM.  Monitoring showed the levels of CO2 in the range of 1200-1600ppm.

#8. During 1992 smoking was banned in classrooms of a small college building.  The students continued to smoke in student lounge and hallways. Several employees and students complaint about the smoke odor to Dean.  Give your suggestions to Dean to solve the problem.

#9. In a transit bus garage, during winter, all the buses were left with engine running in idle mode for the whole night. The 15 minute average concentration of pollutants from the bus were observed as: CO - 176 ppm, SO2 - 90 ppm, and NOx - 550 ppm. What are the possible ventilation methods that can be employed in order to maintain a good indoor air quality.

#10. In a public transit bus, observed from a recent study, with an increase in passenger ridership the CO2 levels increased while SO2 levels decreased. Discuss the possible reasons for this trend and suggest possible ways to overcome this problem.


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