Health Risk Assessment of PM10 exposure among Malaysian Adult Population based on Physical Activity Pattern

Most health advisories related to outdoor physical activity during haze are general in nature. The advisories normally advise everyone to reduce or limit prolonged exertion or heavy exertion without mentioning the acceptable duration for performing outdoor physical activity causing difficulty for public to decide to stop or cancel a particular outdoor or sport event. The aim of this paper is to determine the acceptable duration for performing outdoor physical activity pattern based on API level. Health risk assessment approach that comprises of hazard identification, exposure assessment, dose-response, and risk characterization steps were used to determine the potential inhaled dose and risk associated with performing the physical activity during haze. We have considered many factors that include time spent for physical activity patterns for Malaysian adult, age, physical intensity-specific inhalation rate (m3/min), and the indoor/outdoor ratio of PM10. A hypothetical exposure scenario of PM10 was created using the breakpoints of PM10 concentration for the calculation of respective API levels. The association between physical activity pattern, API level and risk quotient were presented in the form of risk radar diagram. In general, based on the average estimate, everyone should avoid high intensity physical activity and moderate exertion when API reach > 175 and > 200 respectively. Whereas, based on the high estimate, everyone should avoid high intensity physical activity and moderate exertion when API reach > 135 and > 150 respectively. Below the said API, the duration for performing prolonged exertion and heavy exertion should be adjusted according to the API level as stated in the recommended maximum duration for performing physical activity. Reducing the physical activity is an effective strategy to lower the dose of inhaled pollutants and reduce the health risk during poor air quality. Based on the assessment, the recommended maximum duration for performing the physical activity based on API level was established as a guide for the authority or public to plan their activity during poor air quality.​

Potential Health Impacts of Bauxite Mining in Kuantan

Bauxite mining is not known to most Malaysian except recently due to environmental pollution issues in Kuantan, Pahang. Potential impacts are expected to go beyond physical environment and physical illness if the situation is not controlled. Loss of economic potentials, and the presence of unpleasant red dust causing mental distress, anger and community outrage. More studies are needed to associate it with chronic physical illness. While evidences are vital for action, merely waiting for a disease to occur is a sign of failure in prevention. All responsible agencies should focus on a wider aspect of health determinants rather than merely on the occurrence of diseases to act and the need to emphasize on sustainable mining to ensure health of people is not compromised.

Health Risk Assessment of PM10 Exposure among School Children and the Proposed API Level for Closing the School during Haze in Malaysia

During haze, at what level should Air Pollutant Index (API) showed, public or private school be closed is not without controversy and is very much debated. Therefore, the aim of this paper is to objectively quantify the potential inhaled dose of PM10 associated with exposure at school and home microenvironments during haze. The result of the health risk assessment will be used to propose the API level for closing the school during haze episode. A hypothetical haze exposure scenario was created using the breakpoints of PM10 concentration for calculation of API and respective inhaled dose during haze. To determine the potential inhaled dose, we have considered many factors that include time spent for specific physical intensity at school and home microenvironments, age-specific and physical intensity-specific inhalation rate (m3/min), and the indoor/outdoor ratio of PM10. To calculate risk quotient (RQ), the inhaled dose was compared with the health reference dose computed based on the concentration of PM10 in the Malaysian Ambient Air Quality Standard. When considering the specific exposure at each microenvironment (school and home), the potential inhaled dose of PM10 was substantially lower when school is closed for both primary and secondary school. The calculated risk quotient (RQ) indicates that primary school children are likely to be affected at slightly lower PM10 concentration (equivalent to API of 197) as compared to secondary school children. Short duration of high physical activity intensity during school breaks has contributed to a large proportion of inhaled dose among school children indicating the important to avoid physical activities during haze. Based on the assessment, taking into account the uncertainty of risk assessment methodology, we proposed school to be closed when API reach 190 for both primary and secondary schools. These findings and recommendations are only valid for naturally ventilated school and applicable in the context of the current API calculation system and the existing Recommended Air Quality Guideline values in Malaysia. ​

The Effect of Rear Seatbelt Advocacy and Law Enforcement in Reducing Injuries among Passenger Vehicle Occupants in Malaysia

The increase in car usage due to economic prosperity has led to increase in occupant injuries. One way to reduce the injuries encountered by road accident victims is by implementing the rear seatbelt (RSB) law. Rear seatbelt wearing has been proven to save lives. In Malaysia, the implementation of the restraint system for front occupant has started in the 70’s. However, the rear seatbelt enforcement law only came in 2009, after six months of an advocacy program. Prior to the introduction of the rear seatbelt law, rear seatbelt wearing rate was rather low, started to increase gradually during the advocacy period and jumped to the highest level after two month of the enforcement. This paper attempts to assess the effectiveness of the rear seatbelt intervention in reducing injuries among passenger car occupants in Malaysia using the generalized linear model (GLM). In GLM procedure, the dependent variable is the number of people from passenger vehicles that sustained severe and slight injuries, for the study period. The study period selected covers six months before implementation, six months during advocacy program, and six months after the law is implemented. The independent variables considered are enforcement and balik kampung activities (both are dummy variables) and time effect. Our results suggest that RSB intervention (p-value= 0.0001) had significantly reduced the number of people sustained serious and slight injuries by about 20%. The implementation of change in the RSB law has benefited not only in reducing the number of injuries but also result to great impact to the health outcomes.

Rear Seatbelt Usage in Malaysia: Findings from Roadside Observations and Surveys

Despite of its importance for preventing fatal and severe injuries in an event of a crash, limited studies were conducted to find out the status of seatbelt use among rear passengers in Malaysia. This study was conducted to the determine seatbelt use among rear passengers in Malaysia in conjunction with the introduction of the rear seatbelt law that took effect on 1st January 2009. Two methods were used; the roadside observations and surveys. A total of 4180 rear passengers were observed during the road side observation and 793 rear passengers were interviewed in the survey. About 41.8 % (95 % CI: 38.3, 45.4) of rear passengers interviewed reported that they “Always/Often’ wore safety belts, while roadside observation recorded slightly lower rate (36.2 % [95 % CI: 34.8, 37.7]). Based on the roadside observation method, male rear passengers were more likely to use rear seatbelts as compared to female rear passengers (with Odd Ratio: 1.17 (95 % CI: 1.03, 1.33)). Both methods consistently reported that rear passengers of Multipurpose Vehicle (MPV)/Sport Utility Vehicle (SUV) (survey method “always wear”: 39.3 %, Odd Ratio: 2.02 [95 % CI: 1.13, 3.61], roadside observation method: 51.9 %, Odd Ratio: 2.23 [95 % CI: 1.89, 2.62]) were two times more likely to wear seatbelts as compared to rear passengers of a car. The two research methods indicate rear passengers in Malaysia were consistently having low seatbelt usage rate. As the rear seatbelt advocacy and enforcement programme are new in Malaysia, efforts to advocate rear seatbelt use should be strengthened. The changes in rear seatbelt usage rate need to be tracked regularly and as an alternative to roadside observation method, interview survey method could be used to measure the seatbelt usage rate and to identify the reason for not using safety belt among rear passengers.