Assessment of Toilet ’ s Indoor Air Quality in Relation to Asthmatic People

This paper presents an assessment on toilet’s indoor air quality on asthmatic people. The assessment was carried out by measuring temperature, relative humidity, air velocity and SO2 in the 4 selected toilets which are naturally ventilated. The measurements used two equipments that are Yes Plus LGA meter and Anemometer. It was done in early morning and break hours for 10 minutes within three (3) days consecutively. This study found that SO2 concentration in toilet 1 exceeded the threshold limit value of SO2 for 10 minutes exposure which means this toilet potentially trigger asthmatic symptom for those asthmatic people who frequently used this toilet. High concentration of SO2 was due to inadequacy of air velocity in this toilet. Inadequacy of air velocity means less ventilation and thus, increased the humidity which can stimulate the growth of fungi/mold in the toilet that affects asthmatic people.


Introduction
Indoor Air Quality (IAQ) is a terminology of air quality within and around buildings which pertinent with health and comfort of indoor occupant (Muhamad-darus et al., 2011;Murdoch & Lloyd, 2010).The duration of time that people spent indoor and the risk to health posed by indoor air are the most issue that encourage researchers to conduct the study on indoor air (Frontczak & Wargocki, 2011;Lee, 1997;Massey et al., 2009).In addition, several findings of IAQ studies from previous researchers indicated that coarse particulate matter (PM 10 ) which is less than 10 micrometers in diameter (Brunekreef & Forsberg, 2005;Donaldson et al., 2000;Karakatsani et al., 2012;Zhang, 2005), fine particulate matter (PM 2.5 ) which is less than 2.5 micrometers in diameter (Brunekreef & Forsberg, 2005;Karakatsani et al., 2012) and Sulfur Dioxide (SO 2 ) (Awbi, 1991;Guo, 2012;Luttinger & Wilson, 2003;Restrepo, 2012;Tseng et al., 2012) in particular concentration could lead adverse effect for human inhalation such as asthmatic symptoms.However, the exposure of SO 2 on human inhalation for asthmatic people in a concise time at particular concentration gives more significant effect to trigger the asthmatic symptoms as compared to PM 10 and PM 2.5 (World Health Organization, 1987).
Asthma is a heterogeneous disorder of the conducting airways involving chronic inflammation, declining function and tissue remodeling (Murdoch & Lloyd, 2010).For asthmatic individuals, the inflammation causes wheezing, breathlessness, chest tightness and cough particularly at night and/or early morning (Bousquet et al., 2000).There are various researches on the effect of SO 2 exposure to asthmatic people.Koren (1995) had exposed asthmatic people within 20 minutes of SO 2 at 0.25 ppm and found it affect to the bronchosconstriction function which finally lead to asthmatic symptom.In other situation, a laboratory experiment was conducted which involves 7 asthmatic people exposed to 0.5 ppm of SO 2 for 10 minutes and resulted to 3 people having wheezing and breathlessness (Sheppard et al., 1980).Furthermore, Balmes et al., (1987) had carried out a study on the effect of exposure to a humidified air for 5 minutes and SO 2 in the range of 0.5 -1 ppm for 1,3 and 5 minutes on 2 females and 6 males of non-smoking asthmatic adult.They found that bronchoconstriction function increase the Spesific Airway Resistance (SRaw) above baseline with respect to the exposure time and concentration.Additionally, the other asthmatic triggers are smoke and humidity (Al-anzi & Salman, 2011).Smoke is a mixture of smoke from the burning end of a cigarette, pipe or cigar and it exhaled by the smoker that is often found in homes, toilets and car where smoking is allowed.Besides, humidity can affect to the growth of mold and commonly found in the toilet, kitchen and the basement (Al-anzi & Salman, 2011) Based on the findings of previous studies which had been described above, it can be concluded that the exposure of SO 2 in concise time is the main problem that could have effect on human inhalation.Subsequently, toilet in university is one of public facilities which frequently used either by staff or student in concise time.Thus, it motivates to assess its IAQ level in order to compare with the Threshold Limit Value (TLV).

A. Site Description
This study was conducted on 4 selected toilets at Faculty of Civil and Environmental Engineering of Universiti Tun Hussein Onn Malaysia.The selected toilets (2 for gents and 2 for women) are naturally ventilated through opening of windows.Table 1 describes the characteristics of selected toilets.The measurements were conducted twice a day (in early morning and noon during break hours) for 10 minutes within 3 consecutive days.The measured parameters are air temperature, relative humidity and SO 2 concentration which are measured by using Yes Plus LGA Meter and air velocity by using Anemometer.These equipments were placed vertically at a height of 1.2 m from the floor.During the measurement periods, the selected toilets function as usual with several users as in table 1.All the data gathered are analysed using descriptive statistical approach which includes mean, maximum and minimum values calculated using Microsoft Excel and presented into graph and bar chart.

Results and Discussion
The parameters of IAQ considered in this study are temperature, relative humidity, air velocity and SO 2 concentration.The measured values of all the parameters and the analysis on the data are presented in this section

Temperature and Relative Humidity
The temperature and humidity are measured during 10 minutes duration in 3 days continuously in all the 4 toilets involved.The average values of temperature are presented as in figures 1 and 2 while relative humidity is presented as in figures 3 and 4. Figure 1 shows the highest recorded temperature in the morning is 30 °C in the toilet 1 or toilet 2 at 2 nd day of and also in the toilet 1, toilet 2, or toilet 4 at 3 rd day of the measurement.For the lowest recorded temperature is 29 °C at 1 st day of the morning measurement in toilet 1, toilet 2, toilet 3 and toilet 4. Subsequently, for temperatures at noon time, the highest recorded value is 31 °C at the toilet 4 at 2 nd day of noon time measurement and at the toilet 2 at 3 rd day of the measurement.For the lowest recorded temperature at noon time is 28.5 °C which is at the toilet 1 at 1 st day of the measurement.For the morning measurement as in figure 3, the highest average relative humidity measured is at 1 st day of toilet 1 or toilet 2 with the value of 94.5%.For the lowest case, it was achieved at the 3 rd day with the value of 82.5% in toilet 4. For the noon measurement as in figure 4, the highest value is at the 1 st day with the value of 91.5% for toilet 1 and for the lowest is at 3 rd day with the value of 74.5% for toilet 2. Al-anzi and Salman (2011) had stated that indoor humidity is one of the factors that contributes to asthmatic symptoms to asthmatic people.Since most of the toilets are experiencing high humidity thus this will trigger asthmatic symptoms for those asthmatic people who had frequently used this toilet.

Ventilation Rate
The air velocity was also measured for 10 minutes duration in all the 4 toilets in the morning and at noon time within 3 days period.The measured values are tabulated as in table 2. For morning measurement, the table shows that the highest air velocity is at toilet 2 with the value of 0.132 m/s on the 1 st day of the measurement and for the lowest value is in toilet 1 with 0.051 m/s on the 3 rd day of the measurement.For noon situation, the highest value is in toilet 3 with 0.26 m/s on the 3 rd day and the lowest value is 0.05 m/s in toilet 4 also on the 3 rd day of the measurement.These air velocity values are used to calculate airflow and thus, to determine the ventilation rate experienced by all the toilets.The airflow is calculated using the following formula: The calculated airflows of the toilets are presented as in figures 5 and 6.For monring condition in figure 5, the highest calculated airflow is at toilet 2 with the value of 1.337 m 3 /s on the 1 st day of measurement and the lowest is at toilet 1 on the 3 rd day of measurement with the value of 0.463 m 3 /s.For noon time session, the highest of airflow is at toilet 1 with the value of 1.97 m 3 /s on the 2 nd day of measurement and the lowest is 0.05 m 3 /s at toilet 4 on the 3 rd day of measurement.Figure 7 for morning session, indicates the highest ventilation rate is 1233.83l/s/p in toilet 3 and for the lowest value is 154.23 l/s/p at toilet 1 on the same 1 st day of measurement.In the afternoon, the highest value is 1028.19l/s/p at toilet 4 on the 1 st day of measurement and the lowest is 157.66 l/s/p at toilet 4 on the 3 rd day of measurement.These results indicated that few of toilets are experiencing ventilation rate that are lower than the standard requirement of CIBSE ( 2001)

SO 2 Concentration
The SO 2 concentrations in all the 4 toilets were measured for 10 minutes duration in the morning and at noon time in 3 consecutive days.The measured SO 2 concentrations are as in figures 9 and 10.The measured SO 2 from all the toilets are compared to the TLV of SO 2 exposure which is 0.4 ppm (Protection, 2004; The National Advisory Committe for Acute Exposure Guideline Levels for Hazardous, 2008).
Figure 9. Measured morning SO2 Figure 10.Measured noon SO2 Figure 9 for morning measurement, SO 2 concentrations in toilet 1 and 4 exceeded the TLV of SO 2 with the value recorded up to 0.5 ppm.However, for noon time, only toilet 1 experience SO 2 concentrations exceeding the TLV up to 0.5 ppm.This situation is due to the inadequacy of air velocity/ventilation to dilute the indoor SO 2 pollutant.Besides that, in toilet 1 there occupants who are smoking during the measurement period were conducted.

Conclusion
The IAQ study in 4 selected toilets was carried out by measuring humidity, temperature, air velocity and SO 2 for assessing the conditions of the toilets that could trigger asthmatic symptom for those asthmatic people who are frequently used the toilets.The findings that can be drawn from this study are as follows: 1) It was found that SO 2 concentration in toilet 1 exceeded the TLV of SO 2 exposure for 10 minutes.This means that the toilet has the potential to trigger asthmatic symptom for those asthmatic people who frequently used this toilet.
2) Inadequate of air velocity/ventilation in toilet 1 for diluting indoor pollutant such as SO 2 contributes to the increment of SO 2 concentration.Additionally, indoor air humidity which was recorded indicates that this toilet is humid and it can affect to the growth of mold which also can trigger to asthmatic symptoms (Al-anzi & Salman, 2011).
3) The behavior of toilet user such as smoking at toilet can affect to the increases of indoor air pollutants which again increase the potential of trigerring asthmatic symptoms

Table 1 .
Characteristics of the selected toilets

Table 2 .
Measured Air Velocity in the Toilets