**2. Physical and psychological health impacts on public transport commuters: evidence in Malaysia**

In Malaysia, a swelling urban population and increased column of motorized traffic in cities have resulted in severe air pollution affecting the surrounding city environment as well as the health of people in the cities. The number of commuters and commute durations has increased substantially in recent decades. People in the city are spending long hours traveling to and from work. Most commuters are exposed to vehicle emission during transit (**Figure 1**). Considering that air pollution caused by traffic is the scourge of many modern cities worldwide and likewise in Malaysia, we conducted a study to examine the health impact of commuting and the mitigation measures practiced by public transport commuters. Presently, the understanding of the impact of air pollution from congestion on roads on the health of people in Malaysia who are exposed during their daily commute is very limited. Such a study is highly warranted and will be used to inform policy making related to traffic and air quality management and mitigation intervention in terms of health effects.

From June to October 2016, a total of 800 public transport commuters in urban cities in the heart of Selangor, Malaysia, were interviewed face to face. The commuters were approached at the Light Rail Transit train stations along the Kelana Jaya and Ampang lines in the state of Selangor, Malaysia. In the interview, self-reported adverse health effects (both physical health, 15 items, and psychological health, 7 items) associated with exposure to atmospheric air pollutants during the daily commute were queried. Self-reported control measures used by participants to mitigate their exposure to atmospheric air pollutants were also assessed.

The physical effects of air pollution on human health has been studied and reported more than the psychological health impacts. However, the impact of air pollution on psychological health is equally prominent. In an animal model, exposure to exhaust emissions increased anxiety- and depression-like behavior and led to impaired memory in rats [48]. Few studies reported psychological health impacts in Western countries [49, 50]; however, psychological health impacts of being exposed to vehicular traffic-related pollutants have rarely been evident in the Asian region. In this study, as shown in **Figure 3**, the most common psychological impact associated with exposure to air pollution during the daily commute was stress (13.0%), followed by insomnia (5.0%) and feeling moody and anxious (3.6%). Depression was reported by 1.1% of respondents. Although the proportion of psychological health effects experienced are lower than that of physical health effects, mental and emotional well-being is essential to

Commuting on Public Transport: Health Risks and Responses

http://dx.doi.org/10.5772/intechopen.79694

43

overall health. The proportions, although low, have significant clinical implications.

In this study females and the older age group reported higher levels of overall adverse physical and psychological health impacts. However, there were no differences in adverse health outcomes by income and educational levels. As the study is cross-sectional and cannot be used to infer causality, future longitudinal studies are needed to confirm the causal relationship between exposure to road traffic pollution and health impacts. Furthermore, this study recorded self-reported assessment of symptoms and thus was subject to self-reporting bias.

**Figure 4** shows the proportion of control measures undertaken by respondents to reduce exposure to atmospheric pollutants during their daily commute. Despite exposure to atmospheric air pollutants during their daily commute, the vast majority of the study participants reported never or rarely practicing control measures to alleviate the adverse impact of air pollution during their daily commute. Relatively higher proportions reported practicing healthcare measures such as drinking more water and increasing their consumption of fruits and vegetables rather than using respiratory protection. On a positive note, consuming a healthy diet and drinking water may help to improve the body's immune system and alleviate the adverse impacts of air pollution [46]. Although face mask protection is widely used by many commuters in many cities worldwide and regarded as the most common and effective means of reducing inhalation of atmospheric air pollutants, the majority of the study

**Figure 3.** Proportion of the sample reporting adverse psychological health effects experienced during the daily commute.

**Figure 1.** Commuters exposed to vehicle emission during transit.

**Figure 2.** Proportion of adverse physical health effects experienced (%) during the daily commute.

The majority (56.5%) of respondents were aged 30 years and below (mean age, 30.8 years; standard deviation, 6.6; age range, 18–54 years). The ethnic and gender distribution of the study participants closely matched that of the general Malaysian population. A total of 41% of the study respondents spent more than 1 hour commuting by public transport daily. When the respondents were queried on adverse physical health effects they experienced from exposure to air pollution during their daily commute, as shown in **Figure 2**, the highest percentage reported physical fatigue or weakness (35.5%), followed by coughing (23.6%). A considerable proportion reported headache (16.1%), light-headedness (14.6%), and breathing difficulties (14.5%). Air pollution has a wide range of effects on human health. This study evidenced the experience of various physical health impacts commonly associated with exposure to atmospheric air pollutants by daily public transport users.

The physical effects of air pollution on human health has been studied and reported more than the psychological health impacts. However, the impact of air pollution on psychological health is equally prominent. In an animal model, exposure to exhaust emissions increased anxiety- and depression-like behavior and led to impaired memory in rats [48]. Few studies reported psychological health impacts in Western countries [49, 50]; however, psychological health impacts of being exposed to vehicular traffic-related pollutants have rarely been evident in the Asian region. In this study, as shown in **Figure 3**, the most common psychological impact associated with exposure to air pollution during the daily commute was stress (13.0%), followed by insomnia (5.0%) and feeling moody and anxious (3.6%). Depression was reported by 1.1% of respondents. Although the proportion of psychological health effects experienced are lower than that of physical health effects, mental and emotional well-being is essential to overall health. The proportions, although low, have significant clinical implications.

In this study females and the older age group reported higher levels of overall adverse physical and psychological health impacts. However, there were no differences in adverse health outcomes by income and educational levels. As the study is cross-sectional and cannot be used to infer causality, future longitudinal studies are needed to confirm the causal relationship between exposure to road traffic pollution and health impacts. Furthermore, this study recorded self-reported assessment of symptoms and thus was subject to self-reporting bias.

**Figure 4** shows the proportion of control measures undertaken by respondents to reduce exposure to atmospheric pollutants during their daily commute. Despite exposure to atmospheric air pollutants during their daily commute, the vast majority of the study participants reported never or rarely practicing control measures to alleviate the adverse impact of air pollution during their daily commute. Relatively higher proportions reported practicing healthcare measures such as drinking more water and increasing their consumption of fruits and vegetables rather than using respiratory protection. On a positive note, consuming a healthy diet and drinking water may help to improve the body's immune system and alleviate the adverse impacts of air pollution [46]. Although face mask protection is widely used by many commuters in many cities worldwide and regarded as the most common and effective means of reducing inhalation of atmospheric air pollutants, the majority of the study

The majority (56.5%) of respondents were aged 30 years and below (mean age, 30.8 years; standard deviation, 6.6; age range, 18–54 years). The ethnic and gender distribution of the study participants closely matched that of the general Malaysian population. A total of 41% of the study respondents spent more than 1 hour commuting by public transport daily. When the respondents were queried on adverse physical health effects they experienced from exposure to air pollution during their daily commute, as shown in **Figure 2**, the highest percentage reported physical fatigue or weakness (35.5%), followed by coughing (23.6%). A considerable proportion reported headache (16.1%), light-headedness (14.6%), and breathing difficulties (14.5%). Air pollution has a wide range of effects on human health. This study evidenced the experience of various physical health impacts commonly associated with exposure to atmo-

**Figure 2.** Proportion of adverse physical health effects experienced (%) during the daily commute.

spheric air pollutants by daily public transport users.

**Figure 1.** Commuters exposed to vehicle emission during transit.

42 Air Pollution - Monitoring, Quantification and Removal of Gases and Particles

**Figure 3.** Proportion of the sample reporting adverse psychological health effects experienced during the daily commute.

**Figure 4.** Proportion of respondents reporting the use of control measures during daily commuting.

respondents (74.6%, n = 597) reported never or rarely using a face mask. Face mask protection is not common among commuters in Malaysia and is rarely seen among the public, even on smoke-engulfed busy streets. Facial mask in Malaysia is inexpensive and readily available in most pharmacy outlets. There is a need to know if there is a feeling of embarrassment among the Malaysian public at being seen wearing a facial protection masks as face mask use in the community is not widespread (**Figure 5**), or reluctance to use a face mask is due to the perception of discomfort along with a feeling of difficulty breathing in hot and humid weather. In Japan, China, and Hong Kong, wearing a surgical mask is a social norm [51]. The use of a facial mask in tropical countries of Southeast Asia, such as Indonesia, India, and Malaysia, is relatively less common. If face mask usage becomes widespread and commonly seen, perhaps more people will be likely to use them. In this regard, more publicity is needed to encourage widespread use of face mask protection against atmospheric air pollutants in cities. Therefore, reluctance or barriers to the use of face masks during the daily commute or while on streets with polluted air are issues that need further investigation. The use of facial masks should be encouraged in Southeast Asian countries.

people with chronic respiratory disease [54]. In a separate report, we compared the use of a facial protection mask and an N95 mask among commuters in the event of severe haze, and increases in the use of both facial protection masks and N95 masks were reported [55]. Nevertheless, the proportion of the population that uses N95 masks is still low: only 66.0% of respondents reported using N95 masks while commuting during severe haze [55]. The haze phenomenon in Malaysia is often due to illegal burning of forests and peat and forest fires from neighboring countries. In the event of severe haze, respiratory protection is required when going outdoors and especially among commuters who are already exposed to vehicle emissions. While a face mask may be effective at filtering large particles, a face mask, by design, does not filter small particles in the air such as vehicle emissions and airborne particles. In contrast, an N95 is a respiratory protective device designed to achieve a close facial fit and is more efficient in the filtration of small particles. Therefore, using an N95 respirator which provides a good fit and high filtration should be highly recommended to public trans-

Commuting on Public Transport: Health Risks and Responses

http://dx.doi.org/10.5772/intechopen.79694

45

**Figure 5.** Wearing a mask to reduce inhalation of air pollutant is not a common sight in Malaysia.

The majority of respondents reported never or rarely trying to commute using alternative transportation as much as possible. These findings imply the considerable need to encourage as much as possible the use of alternative transit mode options while traveling around or to the city to work. Carpooling may help reduce contact with atmospheric air pollutions and

port commuters.

This study also found poor usage of N95 face protection. Although the use of simple surgical mask protection is recommended for commuters and has been found to have beneficial cardiovascular effects of reducing exposure to particulate air pollutants [38], the use of N95 face protection is more effective. Particles smaller than 2.5 μm are widespread in vehicle emissions and absorbed into the bloodstream, initiating the pro-inflammatory cascade, which leads to many adverse health effects. The N95 is a US government-certified mask that blocks 95% of particulate matter (PM) smaller than 2.5 μm—or even smaller, at 0.3 μm. Emission of PM2.5 from road vehicles is an important source of atmospheric air pollution in cities. Consequently, the levels of PM2.5 near urban roadsides are consistently high [52]; therefore, the use of N95 will ideally offer better protection. In Malaysia, the prevalence of normal surgical mask use is low; therefore, enhancement of use of N95 may require extra effort. The public, especially daily commuters, should be made aware that wearing an N95 mask is more useful in avoiding the detrimental effects of ambient air pollutants [53] and is especially recommended for Commuting on Public Transport: Health Risks and Responses http://dx.doi.org/10.5772/intechopen.79694 45

**Figure 5.** Wearing a mask to reduce inhalation of air pollutant is not a common sight in Malaysia.

respondents (74.6%, n = 597) reported never or rarely using a face mask. Face mask protection is not common among commuters in Malaysia and is rarely seen among the public, even on smoke-engulfed busy streets. Facial mask in Malaysia is inexpensive and readily available in most pharmacy outlets. There is a need to know if there is a feeling of embarrassment among the Malaysian public at being seen wearing a facial protection masks as face mask use in the community is not widespread (**Figure 5**), or reluctance to use a face mask is due to the perception of discomfort along with a feeling of difficulty breathing in hot and humid weather. In Japan, China, and Hong Kong, wearing a surgical mask is a social norm [51]. The use of a facial mask in tropical countries of Southeast Asia, such as Indonesia, India, and Malaysia, is relatively less common. If face mask usage becomes widespread and commonly seen, perhaps more people will be likely to use them. In this regard, more publicity is needed to encourage widespread use of face mask protection against atmospheric air pollutants in cities. Therefore, reluctance or barriers to the use of face masks during the daily commute or while on streets with polluted air are issues that need further investigation. The use of facial masks should be

**Figure 4.** Proportion of respondents reporting the use of control measures during daily commuting.

44 Air Pollution - Monitoring, Quantification and Removal of Gases and Particles

This study also found poor usage of N95 face protection. Although the use of simple surgical mask protection is recommended for commuters and has been found to have beneficial cardiovascular effects of reducing exposure to particulate air pollutants [38], the use of N95 face protection is more effective. Particles smaller than 2.5 μm are widespread in vehicle emissions and absorbed into the bloodstream, initiating the pro-inflammatory cascade, which leads to many adverse health effects. The N95 is a US government-certified mask that blocks 95% of particulate matter (PM) smaller than 2.5 μm—or even smaller, at 0.3 μm. Emission of PM2.5 from road vehicles is an important source of atmospheric air pollution in cities. Consequently, the levels of PM2.5 near urban roadsides are consistently high [52]; therefore, the use of N95 will ideally offer better protection. In Malaysia, the prevalence of normal surgical mask use is low; therefore, enhancement of use of N95 may require extra effort. The public, especially daily commuters, should be made aware that wearing an N95 mask is more useful in avoiding the detrimental effects of ambient air pollutants [53] and is especially recommended for

encouraged in Southeast Asian countries.

people with chronic respiratory disease [54]. In a separate report, we compared the use of a facial protection mask and an N95 mask among commuters in the event of severe haze, and increases in the use of both facial protection masks and N95 masks were reported [55]. Nevertheless, the proportion of the population that uses N95 masks is still low: only 66.0% of respondents reported using N95 masks while commuting during severe haze [55]. The haze phenomenon in Malaysia is often due to illegal burning of forests and peat and forest fires from neighboring countries. In the event of severe haze, respiratory protection is required when going outdoors and especially among commuters who are already exposed to vehicle emissions. While a face mask may be effective at filtering large particles, a face mask, by design, does not filter small particles in the air such as vehicle emissions and airborne particles. In contrast, an N95 is a respiratory protective device designed to achieve a close facial fit and is more efficient in the filtration of small particles. Therefore, using an N95 respirator which provides a good fit and high filtration should be highly recommended to public transport commuters.

The majority of respondents reported never or rarely trying to commute using alternative transportation as much as possible. These findings imply the considerable need to encourage as much as possible the use of alternative transit mode options while traveling around or to the city to work. Carpooling may help reduce contact with atmospheric air pollutions and


should be encouraged. As indicated above, carpooling by Uber and GrabCar that allow more than two persons per vehicle would reduce the chance of exposure while being out on the road or waiting at stops or stations while minimizing number of private cars on the road.

**Total physical and psychological health experience** 

Commuting on Public Transport: Health Risks and Responses

http://dx.doi.org/10.5772/intechopen.79694

**P value**

47

**Score 5–22 (n = 116)**

**score during daily commute days**

**Score 0–4 (n = 684)**

Yes 309 (38.6) 266 (86.1) 43 (13.9) 0.758

Yes 292 (36.5) 255 (87.3) 37 (12.7) 0.297

1 hour and below 472 (59.0) 412 (87.3) 60 (12.7) 0.102

Score 0–8 440 (55.0) 371 (84.3) 69 (15.7) 0.314

No 491 (61.4) 418 (85.1) 73 (14.9)

No 508 (63.5) 429 (84.4) 79 (15.6)

>1 hour 328 (41.0) 272 (82.9) 56 (17.1)

Score 9–18 360 (45.0) 313 (86.9) 47 (13.1)

**Table 1.** Factors associated with total physical and psychological health experience score (n = 800).

Smoking status

Living near a highway

**Control measures**

Total control measure score

Duration spent commuting by public transport (hours)

As shown in **Table 1**, further investigation of the association between control measures and overall physical and psychological health impacts found that respondents with lower use of control measures experience a higher total health impact. It was also found that those who spend longer commuting were more likely to report higher overall physical and psychological health impacts. However, none of the associations were statistically significant; therefore, further studies are needed to verify these associations. Of note, the absence of significant differences between control measures and health impact found in this study could also imply the need to enhance control measures among people who experience a higher health impact. Ideally those who experience a higher health impact should practice greater mitigation measures than those with lower health impacts. Consequently, our findings may imply that commuters in the city of Kuala Lumpur, in particular those who experience a higher health impact, should be encouraged to carry out greater mitigation practices against exposure to atmospheric air pollution during the daily commute. We also found higher health impact score among those with longer commuting duration, although the association is not statistically significant. Further studies are needed to confirm this finding. Of note, this is a cross-sectional study; therefore, the cause and effect relationship between control measures and health impact cannot be established.


**Table 1.** Factors associated with total physical and psychological health experience score (n = 800).

**Total physical and psychological health experience** 

**P value**

**Score 5–22 (n = 116)**

**score during daily commute days**

**Score 0–4 (n = 684)**

30 and below 452 (56.5) 387 (85.6) 65 (14.4)

46 Air Pollution - Monitoring, Quantification and Removal of Gases and Particles

>40 83 (10.4) 67 (80.7) 16 (19.3)

Female 376 (47.0) 314 (83.5) 62 (16.5)

Married 386 (48.3) 328 (85.0) 58 (15.0)

Malay 388 (48.5) 332 (85.6) 56 (14.4)

 Indian 138 (17.3) 115 (83.3) 23 (16.7) Others 3 (0.4) 2 (66.7) 1 (33.3)

Tertiary level 654 (81.8) 560 (85.6) 94 (14.4)

Professional and managerial 419 (52.4) 358 (85.4) 61 (14.6)

 Student 54 (6.8) 46 (85.2) 8 (14.8) Housewife 2 (0.2) 2 (100.0) 0 (0.0)

5000 and below 651 (81.4) 559 (85.9) 36 (14.1)

No 749 (93.6) 644 (86.0) 24 (16.1)

31–40 265 (33.1) 230 (86.8) 35 (13.2) 0.389

Male 424 (53.0) 370 (87.3) 54 (12.7) 0.159

Single 414 (51.8) 356 (86.0) 58 (14.0) 0.689

Chinese 271 (33.9) 235 (86.7) 36 (13.3) 0.636

Secondary level and below 146 (18.2) 124 (84.9) 22 (15.1) 0.796

Skilled/non-skilled worker 314 (40.6) 278 (85.5) 47 (14.5) 0.951

>5000 149 (18.6) 125 (83.9) 56 (14.1) 0.826

Yes 51 (6.4) 40 (78.4) 92 (14.1) 0.521

**Sociodemographic data** Age group (years old)

Gender

Marital status

Ethnicity

Highest education level

Monthly income (MYR)

Occupation

**Other risks** Chronic diseases should be encouraged. As indicated above, carpooling by Uber and GrabCar that allow more than two persons per vehicle would reduce the chance of exposure while being out on the road or waiting at stops or stations while minimizing number of private cars on the road.

As shown in **Table 1**, further investigation of the association between control measures and overall physical and psychological health impacts found that respondents with lower use of control measures experience a higher total health impact. It was also found that those who spend longer commuting were more likely to report higher overall physical and psychological health impacts. However, none of the associations were statistically significant; therefore, further studies are needed to verify these associations. Of note, the absence of significant differences between control measures and health impact found in this study could also imply the need to enhance control measures among people who experience a higher health impact. Ideally those who experience a higher health impact should practice greater mitigation measures than those with lower health impacts. Consequently, our findings may imply that commuters in the city of Kuala Lumpur, in particular those who experience a higher health impact, should be encouraged to carry out greater mitigation practices against exposure to atmospheric air pollution during the daily commute. We also found higher health impact score among those with longer commuting duration, although the association is not statistically significant. Further studies are needed to confirm this finding. Of note, this is a cross-sectional study; therefore, the cause and effect relationship between control measures and health impact cannot be established.
