Characterization of the concentrations .1 Gender difference .1 Gender difference

Considering the main characteristics obtained by the questionnaires, subjects’

concentrations were analysed to estimate possible sources of PAHs and oxy-PAHs.

Gender differences was observed for high molecular compound such indeno (1,2,3-cd) pyrene, Dibenz(a,h)anthracene, Benzo(ghi)perylene and Coronene which concentration were higher in female subjects (independent t-test p>0.05) (Appendix 10).

It has been observed in previous studies that traffic emission are more related with LMW compounds, which are more vulnerable to atmospheric processing as they are less stable (Alam et al., 2013b). Therefore, HMW compounds are reported to be more stable, because the characteristic of vapour –particle partitioning are easier to detect

166 those in the particle phase (Alam et al., 2013a, Anastasopoulos et al., 2012, Bandowe et al., 2014, Kliucininkas et al., 2011). Even though all subjects were exposed to traffic sources, the observed gender difference might indicate that female subjects were exposed to other sources of emission during the day-to-day activities that might include for instance cooking.

6.4.4.2 Seasonal variations

As previously mentioned in the methodology, equal number of subjects for the seasonal sampling was challenging as we depend on the subjects availability and decoration time. However, we made an effort to collect samples during hot and cold seasons. PAH concentrations showed a statistically significant difference between seasons for compound such benzo(a) anthracene during the personal exposure measurements with 0.12 ng m^-3 for the hot and 0.20 ng m^-3 during the cold period.

Home concentration shows statistical differences for compounds like benzo (a) anthracene, Chrysene and coronene showed higher concentration during the cold season. For work concentration chrysene was the only compound that showed seasonal variation with higher values during the cold season. Clearly higher values were observed during cold season.

No statistical differences between the two variables for oxy-PAHs in PE and home (Independent t-test p>0.05) except for 5,12-naphthacene-quinone at the work microenvironments, for which the concentration was observed to be higher during the cold season (0.34 ng m^-3 compared to 0.09 ng m^-3 in the hot season) (Appendix 11).

Possible gas/particle partition of the compound could occur because of the influence of temperature during the winter in the indoor microenvironments (Bandowe et al., 2014). Kitchen concentration were also reported for China with lower concentration

167 during the winter compared to the summer; this is attributable to high ventilation.

Moreover, high winter concentrations can be a result of secondary formation (Ding et al., 2012).

6.4.4.3 Transport mode

Different transport modes for home –work journey were reported, and one way ANOVA test with type III errors was used in PE data from year one to identify any difference between transport modes for all the compounds. According to the TAD, subjects using bus or train also walk, subjects who reported not to work used multiple transport modes during the day, and therefore, they were categorized as multiple transport. Most of the compounds were observed to be statistically similar except for acenaphthylene, acenaphthene, anthracene and benzo(e)pyrene reporting a higher concentration in bus commute mode, while higher concentration of benzo(k) fluoranthene and benzo(e)pyrene was reported for car transport (Table VI-9). However, considering the extreme values, 9^th percentile concentration were observed only for subjects that walk as not 90^th percentile was observed for the rest of the transport modes (Appendix 12).

In general, higher concentration was obtained for compounds such phenanthrene and pyrene in transport mode (~ 1 ng m^-3). However, those are lower than the previous concentrations reported for traffic and background road in Birmingham UK which ranged between 1.5 and 3 ng m^-3 (Alam et al., 2013b) and in Beijing, China (Wu et al., 2014). Interestedly, the results are close to those obtained by (Delgado-Saborit et al., 2013). Oxy-PAHs results show concentration higher than the reported by (Alam et al., 2013b) and (Delgado-Saborit et al., 2013) in which most of the values were lower than 0.3 ng m^-3, while this study registered values ≥ 1.01 ng m^-3.

168 Table VI-9 FIXAT transport mode concentrations (ng m^-3).

ANOVA (p < 0.05) has been used to test for statistically different concentrations between transport modes. Numbers shown in bold were statistically different as indicated by the different letters associated with each. For the concentrations in normal font, there was no significant difference.

Multiple (N=4) Car (N=5) Train (N=6) Bus (N=3) Cycle (N=5) Walk (N=12)

169 Moreover, PAHs and oxy-PAHs obtained concentration were higher than the reported for a rural area in Weybourney England (Alam et al., 2013a). Normally, PAHs and oxy-PAHs are predominantly emitted from vehicle motor emissions or fuel combustion (Wu et al., 2014, Li et al., 2015b). Therefore, PE concentrations were constituted by both sources of emission.

6.4.4.4 Home characteristics

The home concentrations were also analysed, the most used cooking fuel was electricity (N=21) followed by natural gas (N=13). The evaluation of home concentrations did not show a statistical difference between cooking fuel used for PAHs (Appendix 13). However, a higher concentration can be observed for compounds such naphthalene and phenanthrene, pyrene and benzo (a) pyrene. The wood combustion composition profile shows that the most abundant compounds are naphthalene and phenanthrene and this is similar to the obtained results in this study (Shen et al., 2012a, Shen et al., 2011). Pyrene is commonly emitted from petrol or diesel vehicles (Kliucininkas et al., 2011). Benzo(a)pyrene obtained concentrations for natural gas (0.55 ng m^-3) and electricity (0.37ng m^-3) were lower than the reported for wood cooking combustion (700 ng m^-3) and (290 ng m^-3) for LGP (liquid petrol gas) (Bhargava et al., 2004).

Oxy-PAHs like benzo (a) anthracene 7,12-dione concentration were found to be higher for natural gas fuel (independent t-test p>0.05). According to (Albinet et al., 2007), the dominant source of this compound is produced by diesel vehicle. 9,10 anthraquinone, typically emitted by diesel vehicles or generated by photochemical reactions, was observed to have a higher concentration in both fuels analysed (Albinet et al., 2007, Ringuet et al., 2012). High concentrations were also observed for

2-methyl-1,4-170 naphthoquinone and 2-methyl-anthraquinone. These results suggest that indoor concentrations are more related to outdoor infiltration into the indoor more than produced at the indoors.

6.4.4.5 Type of occupation

Work concentrations were analysed based on the occupation of the subjects. No statistical difference was observed between the three occupation categories (one-way ANOVA p>0.05). However, higher concentrations for compounds such phenanthrene, anthracene, fluoranthene and chrysene were00 observed for students compared with office workers (Appendix 14). Most of the students were from University of Birmingham where offices faced the constructions activities that were developed inside the campus (Maertens et al., 2008, Soltani et al., 2015). Indoor PAHs in work environment might be attributable to the outdoor construction activities set in the university.