Air Pollution Exposure & Dose in Children Travelling to School by Bus

Research Proposal

TITLE OF RESEARCH PROPOSAL

 

ASSOCIATION BETWEEN AIR POLLUTION EXPOSURE & DOSE IN CHILDREN TRAVELLING TO SCHOOL BY BUS: A CASE STUDY OF AUCKLAND

 

SUMMARY

Children travelling in school buses are subjected to cumulative air pollutants within the bus-cabin, which effects their health. In this proposed study, a comparison of exposure of air pollutants (carbon monoxide and ultrafine particles) among the children inside the school-bus with surrounding ambient air and children travelling by other non-school buses will be determined. The average exposure to these pollutants along with duration will be calculated and compared with inside school bus, non-school buses and surrounding outside ambient air. This comparative study will further help in determining the dose- response relationship of air pollution exposure among the school children along with its health impact.

 

INTRODUCTION & BACKGROUND

Recent data released by the World Health Organization (WHO) show that air pollution has a vast and terrible impact on child health and survival. Globally, 93% of all children live in environments with air pollution levels above the WHO guidelines. More than one in every four deaths of children under 5 years is directly or indirectly related to environmental risks. Both ambient air pollution (AAP) and household air pollution (HAP) contribute to respiratory tract infections that resulted in 543,000 deaths in children under 5 years in 2016. As children experience the consequences of air pollution in special, specific ways, they deserve to be assessed in a special way.

Children are at greater risk than adults from the many adverse health effects of air pollution, owing to a combination of behavioural, environmental and physiological factors. Children are uniquely vulnerable and susceptible to air pollution, especially during fetal development and in their earliest years. Their lungs, organs and brains are still maturing. Their lungs, are rapidly developing and therefore more vulnerable to inflammation and other damage caused by pollutants. They breathe faster than adults, taking in more air and, with it, more pollutants. Children breath closer to the ground level, where some pollutants reach its peak concentrations.

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Recent data published by the World Health Organization (WHO) show that air pollution has a huge and terrible impact on the health and survival of children. Globally, 93% of all children live in environments with air pollution levels that exceed the WHO guidelines. More than one death in four of children under the age of 5 is directly or indirectly related to environmental risks. Both air pollution (AAP) and domestic air pollution (HAP) contribute to respiratory tract infections that caused 543,000 deaths in children under the age of 5 in 2016. How children experience the consequences of Air pollution in special and specific ways deserves to be evaluated in a special way.

Children are at greater risk than adults of the many adverse health effects of air pollution, due to a combination of behavioural, environmental and physiological factors. Children are particularly vulnerable and susceptible to air pollution, especially during fetal development and in the early years. Their lungs, organs and brain are still maturing. The lungs are developing rapidly and, therefore, they are more vulnerable to inflammation and other damage caused by contaminants. They breathe faster than adults, absorb more air and, with it, more pollutants. Children breathe closer to ground level, where some pollutants reach their maximum concentrations

Urban air pollution is one of the most serious problems faced by the people across the urban centres of the world. Epidemiological research suggests that health of the humans is impacted by air pollutants causing chronic disease in pulmonary and respiratory infections (Hildebrandt K, 2009)(Weinmayr G, 2010)(Künzli N, 2000). Standards prescribed for different air pollutants in the ambient air are usually based on the risks posed to adults. Sensitivity of air pollutants in children is compromised when designing and implementing air pollutant standards.

A health survey conducted by the new Zealand’s Ministry of Health reported that, one in eight adults and one in seven children have asthma due to increase in urban air pollution (Source: New Zealand Health Survey). Children with bronchitis have increased to more than half, from 3984 in 2000 to 6,320 in 2017 (Barnard & Zhang, 2018). This is due to their high inhalation

rate and lung surface area with respect to body weight which makes them more susceptible to air pollution (Dockery, Speizer 1989; Lipsett,1995; Thurston, 2005). They are also at a higher risk of being affected by air pollutants as they have lower immune system (Dockery, D.; Speizer, F; 1989; Lipsett, M; 1995; Thurston, G. D., 2005; Wallace, L. A, 1991; Flachsbart, 1995), increased risk in triggering asthma, decreased lung functioning, blood cancer and increase in susceptibility to lung infections (Bennett and Zeman, 1998).

Further, Sustainable Development Goals (SDGs) recognize the importance of social and environmental factors as determinants of health. All the SDGs are clearly linked to health-related targets, reflecting the growing awareness that health, environmental and poverty alleviation are interconnected –that ensuring healthy lives for all (SDG 3) and making cities inclusive, safe, resilient and sustainable (SDG 11) require universal access to energy (SDG 7) and hinge upon combating climate change (SDG 13). The launch of the 2030 Agenda for Sustainable Development offers an unparalleled opportunity to increase action to address the environmental hazards that undermine children’s health. Implementing evidence-based policies and health practices to protect children from air pollution will, in turn, be essential to realizing the Sustainable Development Agenda: reducing children’s exposure can have enormous benefits due to avoided disease, reduced mortality and improved well-being. Reducing air pollution can also improve health and well-being by slowing climate change.

One of the main contributors of air pollution exposure in children is during their commute to school in a school bus (Behrentz & Sabin, 2005; Wu &Delfino, 2005; Behrentz, Kozawa, 2005; Rea, Zufall, 2001). Studies show that the air pollutant concentration inside the bus cabin is far higher than that of the ambient air outside the bus. Children are exposed to various irritants and substances from vehicle exhaust from bus idling and accumulated pollutants inside the bus cabin along inflow of traffic pollutants. Air pollutants concentrations inside a school bus can be 10 times higher than the background ambient levels (Shikiya et al.,1989; Chan et al., 1991; Lawryk et al., 1996). The on-road UFP concentrations typically range from 10,000 to 500,000 particles/cm3 (Zhu et al., 2007), one or two orders of magnitude higher than typical ambient levels in an urban environment.

Further, Diesel fuelled school buses pose a 23-46 times higher cancer- risk to children when compared to the standards set by the Government (Solomon et al., 2001). As per a report by the Ministry of Transport on Bus Safety in New Zealand, the age limit for a school bus is 26 years and that of a non-school urban bus is 20 years. This shows that the service provided by the school bus is longer than that of a non-school bus.  The accumulation of pollutants inside the bus cabin highly depends on the age and service of the bus which can be of a higher risk to children. Even though children may spend only few hours per day on school buses, the high levels of exposure encountered on-board school buses can add considerably to their daily and annual exposures to air pollutants

Self-pollution of the bus is one of factors that causes in-cabin air pollution (Fitz et al., 2003).  damage or cracks in the crankcase or exhaust system will collect diesel emission in the school bus, as it is more common not check/ regularly maintain the engines as much as the regular buses (Behrentz, 2004; Adar, 2008). As per studies, the concentrations of pollutants inside the cabin is double the amount than roadway concentrations & 4 times higher than ambient concentrations (Beatty & Shamshik, 2011). It is also observed that the Particulate matter & air toxins concentrations are 12 times higher than ambient pollutant levels (Wargo, 2002; Sabin, 2005).

Fig 1: Depiction of concentration of UFPs considerably higher than PM 2.5 concentration inside motor vehicles in various cities from Xu, Bin & Chen (2016)

Apart from the above, the accumulation of pollutants from other vehicles inside the closed compact bus is important to explain variability of on-board concentration (Rodes and Sheldon, 1998). However, the pollution of the vehicular exhaust itself will result in accumulation of pollutants inside the bus (Marshall & Bentertz,2005). The above analysis suggests that efforts to reduce air pollutant needs to be addressed as children are exposed to it throughout their school years, when they are the most susceptible (Dirks & Salmond, 2018)

AIM OF THE RESEARCH

The identification of assessment of Air pollution exposure and its health impact helps to understand the reasons for divergent opinion, without which it will be difficult to develop effective policies. For various reasons, the magnitude of the health problem from exposure to urban air pollution needs to be estimated. Assessment of Dose- Response function is not just a tool for improving our understanding of environmental and health linkages, but it also allows estimates from different sources to be compared and communicated in a standardized format, which supports decisions on priority actions to be undertaken in health and the environment sector. This also helps for prioritizing actions to be taken, when planning to prevent or reduce problems associated with a high disease burden and those preventive actions can be used as input for infrastructure planning.

Further, the aim of this proposed research is to measure the in-cabin air pollution concentration in a school bus and compare the same with the surrounding ambient air quality and with pollutant concentration of non-school buses. The pollutants considered for the proposed study are ultrafine particle counts and Carbon Monoxide concentrations. The study is to be conducted through travelling voluntarily in a school bus to-and-from a specific route designed and measuring the air pollutant concentration exposure on school children.

Such studies have not been conducted in Auckland and will give a clear picture on the in-cabin pollution exposed to school children. If the pollutant concentration is exceeding the ambient air quality standards, alternatives solutions in reduction of the pollutant exposure to children can be drawn from this study. This study will also help in reducing the vulnerability of a school child in contracting various health disorders.

6. PROPOSED RESEARCH

Methods and materials

Study site

A specific route is selected as per the Auckland Transport school bus routes in consideration with the school zone area. Newmarket, an Auckland suburb to the south-east of the central business district is preferred. A total of 15 kms in length was selected for schools situated in the suburbs of New Market. This route is selected as the bus drives takes the bus through relatively higher air polluted area due to traffic input towards CBD. The starting point selected for the route is situated in Glendowie Opposite 411 Tamaki Drive (stop 7344) and ends at Owens Rd by Epsom Girls Grammar Gate (stop 1495). The duration of the bus ride is about 45 minutes to 1 hour. As seen, there are many stops on this route to get to various schools but we measure the dose concentration from longest route, that is from the starting to the end point.

Table 1: Bus Details

 

523 : GLENDOWIE TO EPSOM SCHOOLS

Departs:

7:15am

Operator:

NZ Bus

Serving:

Baradene College, Dilworth School, Diocesan School for Girls, Epsom Girls Grammar, Kings College, Kings School, Remuera Intermediate, Remuera Primary, Saint Kentigern Boys School, Saint Kentigern Girls School, Selwyn College, St Cuthbert’s College

Route:

Opposite 411 Tamaki Drive (stop 7344), Tamaki Drive, Vale Road, Bay Road, Riddell Road, Rochdale Avenue, Chesterfield Avenue, Maskell Street, St Heliers Bay Road, Kohimarama Road, Kepa Road, Purewa Bridge, Orakei Road, Remuera Road, Market Road, Campbell Crescent, Manukau Road, Clyde Street, Margot Street, Mount St John Avenue, Manukau Road, Alpers Avenue, Gillies Avenue, Owens Road, Owens Rd by Epsom Girls Grammar Gate (stop 1495).

Notes:

Last updated 11 July 2018

Source: Auckland Transport, school bus routes. (https://at.govt.nz/bus-train-ferry/timetables/school-timetables/kings-school/)

 

 

Fig 2: School bus route from Glendowie to Epsom schools as seen from Google maps

Traffic

Traffic data is obtained from Auckland council website and the same can be utilized to understand the traffic flow rate during the commute of the school bus considering the morning and evening peak hour periods.

Data collection and instrumentation

The exposure to & accumulation of pollutants like Ultrafine particles (UFP) which is emitted from diesel engines and Carbon Monoxide (CO) which is emitted from petrol engines is measured. The selection of these pollutants is also due to the availability and mobility of the monitoring equipment which is used for studies on personal exposure. The instruments used will be P-Track ultrafine particle monitor (TSI instrument) and a Langan portable carbon monoxide monitor (Langans Products, Inc) which are used in previous studies  (Kaur et al., 2005b; Chan et al., 1999; Flachsbart, 1999; Lui et al., 1994; Wong et al., 2011; Vellopoulou et al., 1998; De Bruin et al., 2004). A participant will help in volunteering as an additional help in carrying out the data collection which will take place inside the bus to and from the starting to the ending point of the commute. Air pollution data will be collected in 10 sec interval of the journey inside the bus. Sampling of data for morning commute will start from the departure of the bus, that is., 7.15 a.m. and end at arrival at around 8.15 a.m. at the end of the journey. The evening commute will start at 3.15 p.m. and end at around 4.15 p.m. depending upon traffic. The data collection will be carried out for around 15 days. The time of the journey will be recorded. 

Pollutant concentration inside a non-school bus will also be collected for comparative studies. The time at the start and end of the journey will be noted along with the time interval. Route and time of the non-school bus will remain the same as the school bus route for better results. Meteorological parameters like temperature, humidity, wind speed & wind direction will be monitored during the travelling time throughout length of the journey.

Bus Characteristics

Data about operating school buses will be collected from Auckland Transport. Bus details like mileage, age, fuel used, type of engine will be complied (Adar & S’Souza 2015). A reference of non-school bus will be selected which resemble the similar characteristics for more accurate results. Pollutant concentration of UFP and carbon monoxide will be measured inside the school bus which travels in a polluted/traffic area and outside the bus at each stop, preferably in the front, where the diesel exhaust of the bus is far off, for obtaining comparative results. This will give the difference between self- pollution accumulated in the bus and the pollution on road (Adar & D’Souza, 2015). Adjacently, the pollutant concentration in a non-school bus will also be monitored. This is to differentiate the accumulation of pollution concentration between a school bus and a non-school bus. Data on ambient air quality obtained from air pollution monitoring sites nearby the school is used for the study.

Data analysis

Carbon monoxide and ultrafine particle matter concentrations will be analysed using time series data analysis based on the exposure. This will be carried out for both selected school bus and non-school buses which travel the same route and at the same time. By using this data average commuter exposure of these pollutants is calculated. The average exposure pollutant concentration is calculated for both the school bus and non-school bus for the fixed time period of the research. This average exposure will be compared with the exposures measured at early morning and evening commute for each of the pollutant measured using statistical analysis (unpaired T tests). The ambient air quality will also be considered at the same time interval during the commute of the school bus. The average of the same will be calculated and compared with that of the school bus concentration. Peak concentrations for both the pollutants will be determined in school bus, non-school bus and ambient air concentrations. Difference in the peak concentrations of both the commutes will be determined during the length of the experiment conducted.

7. TIMELINE AND BUDGET

The timeline for this study will be 15 days.

The estimated cost will be around NZD$ 2000

Sl No

Particulars

Cost

1.

Ethonol for P-track ultrafine particle monitor (TSI Instrument)

$1000/-

2.

Bus fare is 3.75 per ride for 1 month (5 days a week)

$100/-

 

Miscellaneous (Assistant, renting instrument etc)

$400/-

Total

$1475/-

 

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