Task 3. Environmental exposure to airborne particles; Impact of ozone on ultra-fine particles in indoor air.
* Aarón Amado s061110
* Anne-Maja Sollid s100279
* Concorde Mugisha s061961
* Klaus Johannessen s094812
Monday 7th of March 2011
Three different phases underdifferent conditions have been studied. During the first phase an Ozone Meter, a Lasair Particle Measuring System and a P-Trak Ultrafine Particle are measuring the ozone concentration and particles concentration on the air in the empty room and without air freshener or ozone generation. After 10 min an air freshener is placed inside the room getting started the phase number two that will last for 20min. Finally, an ozone generator is placed as well inside the room getting started phase number three that will last 60 min. During each of the three different phases several people will get inside the room in an individual basis in order to evaluate the indoor air quality. In order to obtain the percentage of dissatisfied people with the air quality for each phase the following equation has beenused:
PD=exp(-0,18-5,28* ACCt1+exp( -0,18-5,28* ACCt)*100
PD=Percentage of dissatisfied people with air quality, %
ACC(t)=Average vote of air acceptability
Results and discussion
Part 1. Experiment
The results obtained for the part 1 of the experiment performed are presented in the following section. The measurement of the ozone in the room object of studied has given the following results:Figure 1. Continuous ozone concentration measurement and average ozone concentration during each phase.
First, in order to have a reference point for comparison, the ozone concentration in the outside has been measured. The ozone meter has been placed out of the window of the room for a minute, from 13:57 until 13:58.The average value obtained for the outside conditions was 30 PPB. Rightafter this, the ozone meter was placed inside the room measuring the ozone concentration for the three different conditions studied. In Figure 1 it can be seen that the average value for the ozone concentration for the three different phases does not change much. The slight variations in the ozone concentration during the experiment could be due to the entrance and exit in the room of the persons whoevaluated the indoor air quality.
The measurement of the particles in the room has given the following results:
Figure 2. Lasair particle and P-trak ultrafine particles concentration measurements.
As it can be seen in figure 2 there is a sudden and intense increase in the concentration of particles measured in the room. The average value of particles concentration foe each phase of studyhas been calculated and the results are presented in figure 3.
Figure 3. Average value for particles concentration in air for each phase.
Clearly, the combination of the air freshener and the ozone during the phase number 3 produces a very significant increase in the level of the particles concentration present in the room air.
As stated earlier, during each of the three phases, twelve personshave evaluated the indoor air quality in order to get a sensory assessment of the air under different conditions. The results obtained are presented in figures 4, 5 and 6.
Figure 4. Percentages of dissatisfied people with the air quality for phase 1.
Figure 5. Percentages of dissatisfied people with the air quality for phase 2.
Figure 6.Percentages of dissatisfied people with the air quality for phase 3.
As it can be seen in the different figures the percentage of dissatisfied people with the air quality increases from condition 1 to 3. The percentage of dissatisfied people under condition 2 increases 30% compare to condition 1, while the increase of particles concentration on air is around 18%. The percentage of dissatisfied people...