Assessment of Health Effects and Spatial Variation of Combustion-Related Air Pollutants in Different Environments

Abstract

There is an emerging concern over health significance of the exposure to combustion-related air pollutants, which are considered to give adverse, acute and chronic health effects. Methods were developed ranging from the relative simplicity of colour analysis for particle darkness, through portable real time monitors, to complex GC-MS analysis of pPAH constituents. NO2 and O3 concentrations involving both passive samplers and real-time sensors were determined. A low-cost technique to estimate BC concentrations were also established using filter-based collection and measured using light reflectometer and an office scanner. The field evaluation of portable low power systems of NO2 against reference methods validates the calibration of the real-time monitor to improve measurement resolutions. This study subsequently examines PM, BC and NO2 in three different environments (indoor offices, urban outdoor streets and outdoor experimental hydraulic fracturing site). Indoor measurements of PM, BC and NO₂ were found influenced by the outdoor sources entered through natural ventilation and the location of buildings near the urban roadsides. The use of office equipment such as the printer is suggested to be one of the drivers for higher PM and BC concentrations in the office area. Results indicate that children may have a greater tendency to expose to combustion-related air pollutants near the ground emissions. Results also pointed out that the variation of BC and NO₂ measured in Glasgow central were mainly determined by street topography and rush hour period. Marked elevations of BC and NO₂ concentrations were observed in proximity to industrial fracking equipment sources, where the average was 4 & 2 times higher respectively than measured during walking at the urban Glasgow city centre. This study demonstrates novel approaches to characterise, in a better way, the exposure to combustion related air pollutants, given the air pollutants are varied in time and space linking to the personal exposure. For students who are seeking to delve deeper into the healthcare subject, using healthcare dissertation help to get the most valuable guidance and resources.

1.0 Background

This chapter provides a basic introduction to the study. This chapter grounds the scope of the research with respect to the aims and objective. The chapter briefly presents the framework of this thesis.

1.1 Introduction

Various kinds of pollution have been produced by human activities including air pollution. Poor air quality remains an environmental health challenge where such pollutions are ubiquitous and become one of the greatest dangers to human health, causes 7 million annual deaths globally (WHO, 2014). Research by Lewtas (2007) addressed causal components of combustion-related air pollutants generated by combustion sources and by-products, which pointed out to adverse health outcomes. Common combustion-related air pollutants that draw intense concerns including particulate matter (PM), nitrogen dioxide (NO2), black carbon (BC), ozone (O₃) and other toxic compounds including polycyclic aromatic hydrocarbons (PAHs).

People spent most of their time indoors and moving around outside work, commuting, and recreation where they are inadvertently exposed to a wide and varied sources of air pollutants, particularly from broad combustion sources ranging from fossil fuels, biomass and traffic emissions. Fewer studies have explored to characterise the combustion-related air pollutants meanwhile the focus of number of studies has been on their single pollutants. This is because the related term as combustion-related air pollutants has only been recently recognised and defined. However, better identification of their components under different environmental conditions in indoor and outdoor air is vital where the individual responds differently to the effects of the air pollutants concentrations with age, gender, type of work and health conditions.

Despite the complexity and mixture of combustion related air pollutants, certainly a novel sampling technique using suitable monitors and efficient analytical methods are in a great demand. This also has been highlighted by Steinle et al. (2013) pertaining to the development and application of sampling monitors suitable for exposure measurements. Furthermore, it is necessary to provide accurate estimate of exposure assessment where it is a prerequisite for measuring risk to human health. With recent advances of personal monitors, what are the ideal sampling methods can be directed to assess combustion related air pollutants in different environmental settings?

Aims and objectives

The aim of the proposed research is to throw light on the talent management practices of the organisation and its relation with the performance of the employees and the organisation as a whole. The study would bring new insights into this aspect of human resource management and the extent to which such practices bring benefits for the company.

Atmospheric specimens are collected across the monitoring sites throughout the period of study to address sources of pollution, exposure level and potential health effects. The collection system may expose to environmental time-sensitivity, human activities and duration of monitoring during the sampling exercise (Fan, 2011). This can be directed from the data collection and interpretation of results to the overall sampling quality and validity of an analytical procedure. A sensitive, quick and accurate approach is fundamental to collect and analyse the atmospheric samples in a similar way to assess individual exposure as a point of reference for pollution control measures.

This research focuses on the development of novel approach of combustion related air pollutants including PM, BC and NO2 and subsequently assess these pollutants in both indoor and outdoor settings. The exposure assessment methods comprised of collection of airborne specimens and analysis methods to improve characterisation were developed prior to deploy this monitoring system in the field tests and real-world settings. For this purpose, the collection system should be sensitive, quick, and low-cost and provide high-time resolution data in multiple locations. The sampling applications were extended from laboratory tests to the small locale area and a wider scale; from indoor office areas to the urban walking segments in Glasgow city centre and at hydraulic test site in Poland.

1.2 Scope of the study

This research focuses on the establishment of innovative methods for sampling and analytical techniques, which are subsequently examined exposure to PM, BC and NO2 in the indoor and outdoor environments. In the early stages, the methods were developed for collecting the particle and gaseous specimens using portable filter-based, passive samplers and real-time instruments. The analytical technique to make an assessment simpler and practicable were demonstrated from the particle darkness analysis and gaseous of PM, BC and NO2 to complex and sophisticated systems for PAHs which were conducted in the pilot tests.

This research introduced a non-destructive and low-cost optical analysis of sequentially loaded filter air samples collected during the laboratory test, which in turn illustrate how BC can be estimated from filter reflectance calibrated against co-located micro-aethalometer observations. The method was further tested in the field evaluation in different micro-environments in the ideal collection system to best approximate the BC concentrations. The real time NO2 monitor against O3 sensor and reference analyser were collocated under representative outdoor environment prior to deploying in the actual operating conditions. This will ensure the reliability of the instrument used and their capacity when performing the measurement at the field site, therefore improving the confidence in the measurement made.

Since this research has a focus on the development of relevant exposure measurement strategies for combustion-related air pollutants, the approach to adequately estimate the pollutant concentrations were demonstrated in different environmental settings. The indoor air quality study was conducted in two office building to assess PM, BC and NO2 with the application of identifying air monitors where the performance and feasibility of these instruments were further examined. To better understand the indoor exposures, other air pollutants have also been acknowledged when conducted the indoor air quality assessment, including carbon dioxide (CO₂), ozone (O₃) and nitric oxide (NO). This will also assess how other sensors function instantaneously with equivalent devices.

Using similar developed methods, the exposure assessment was extended to the urban outdoor roadside in Glasgow city centre. This also directed to the complex relationship of the individual with indoor and outdoor air pollution from the role of combustion-related sources in influencing such exposure. The study examines the exposure of PM, BC and NO2 to adult and children in the urban terrain reflecting the near ground vertical variation from combustion sources of city traffic. The study was expanded to include portable BC and NO2 real-time monitors to illustrate the variability of the pollutant profiles at different walking routes. The measurements were also observed during different peak hours when walking through the urban streets. The pollutant data captured by the automatic analysers maintained by the UK air monitoring national network were obtained to compare and validate the measurements from dedicated monitoring exercises.

This study also designed to assess personal exposure to diesel engine exhaust combustion from industrial fracking equipment at an experimental hydraulic fracturing (HF) test site in Poland. This preliminary monitoring event showed how the instrument can be deployed in the real world environment with state-of-arts sampling techniques. This also allowed a detailed insight into a short-term exposure of combustion related air pollutants experienced by the site operators. The application of advanced sampling and analytic techniques will provide better understanding and new perspective of combustion-related air pollutants in order to estimate the values and assist in new standardisation of the combustion-related pollutant metrics.

1.3 Aims and objectives

This research aims to develop novel methods for exposure assessment of combustion-related air pollutants within indoor and outdoor settings. The specific objectives for this study include:

1. To apply an innovative sampling method using a low power sampler for combustion-related air pollutant metrics.
2. To further detail the low cost instrumentation of BC and NO2 in the field evaluation to be used in subsequent exposure assessment.
3. To assess PM, BC and NO2 concentrations within indoor and outdoor settings.
4. To contrast PM, BC and NO2 concentrations within the environmental and personal exposures.
5. To identify whether or not it is possible to estimate the concentration of particular constituents of combustion-related air pollutants such as PM, BC and NO2 for simple marker from different combustion sources.

1.4 Outline of thesis

Generally, the work for this thesis presents the development of methods to assess combustion-related air pollutants in the indoor and outdoor environments through advanced sampling and analytical techniques. As the first approach to systematically evaluate the capability and illustrate the potential applications of the developed techniques, the field tests have been carried out to the possible combustion sources where the individuals are exposed during working and commuting in different sampling locations. This also will examine the relative contributions of indoor and outdoor emission sources and links the personal exposures to combustion-related air pollutants. This thesis comprises eight chapters with the basic introduction described in this chapter.

Chapter 2 reviews the components of combustion-related air pollutant, which are relevant for the selective approach to enable the interpretation of the findings through methods assessment of these air pollutants. The chapter reviews the need for state-of-art methods to assess the combustion-related air pollutants and methods for exposure characterisation were pointed out where the pollutants may have patterns of differences from their sources and behaviours.

Chapter 3 describes the development of the sampling and analysis techniques. The use of selected instrument to measure PM, BC, NO2 and PAHs and the pilot tests were demonstrated to better evaluate the components of combustion-related air pollutants.

Chapter 4 presents the field evaluation exercises conducted for further work described in the pilot tests to be extended in exposure assessment in the indoor and outdoor settings in order to estimate concentrations of BC and NO2 using newly developed cost-effective techniques and portable real-time sensors.

Chapter 5 assesses PM, BC and NO2 in the university offices with different mean of ventilations using filter-based, passive samplers and real-time monitors. Additional measurements for CO2, O3 and NO were also made.

Chapter 6 assesses PM, BC and NO2 using static and mobile platforms and wearable real-time sensors in the urban Glasgow city centre. The identified low cost instrumentation from previous monitoring assessment was used to estimate the combustion-related air pollutants near the urban roadsides.

Chapter 7 presents field tests to measure BC and NO2 using selected portable air monitors at the simulation hydraulic fracking site in Poland. This study case provides an attempt using field evaluation technique to characterise combustion-related air pollutants in the real-world situation.

Chapter 8 summarises the key findings, the contribution of this thesis and possible avenues for future research to enhance the understanding of key pollutants from combustion sources. Therefore, this will quantify the exposures in the interest of health risks estimation with the combination of the exposure science and engineering.