Assessment- Essay

Length 6 - 8 pages.

Assessment Details

The following questions are designed to assess your assimilation and application of knowledge to the practice of risk assessment in occupational hygiene. You should attempt all of the questions. You should include references to source documents.

1. For each of the following air contaminant exposures, state the current Australian exposure standard, describe appropriate methods to sample and analyse each substance, to allow comparisons with the exposure standards as part of a risk assessment and briefly explain why you selected each sampling method:

a) Coal dust exposure in a miner working at the face in longwall mining (all types).

b) Diesel exhaust exposure during a longwall move at an underground coal mine

c) Benzene exposure in the oil & gas industry

2. From the information provided from the scenario below, write the Hygiene Survey Report for the exposures identified therein. The report should include:

• An introduction and background to the survey

• A description of the sampling strategy used and an outline of the sampling and analytical methods employed to assess the exposure, to produce the results that are provided

• Appropriate interpretation and discussion of the results (You do not need to copy out the result tables into your report.)

• Recommendations for control and management to minimise any exposure risks identified.

Scenario

Air pollution has been a significant issue in recent times, and involves both indoor and outdoor environments. There are numerous adverse health effects connected to air pollution, which includes, but is not limited to, pulmonary tuberculosis, various cancers, perinatal disorders etc. For the purpose of this exam we will focus on measurements that was taken at schools in urban and suburban areas, of which the urban schools were in close proximity to a petrochemical factory.

Most people spend approximately 70 - 90 % of their time indoors, whether it be at work, at school, at home etc. Resent research indicates that indoor air pollution may be responsible for approximately 2 million premature deaths in developing countries and a contributing factor to about 4% of the global burden of disease. Studies also indicate that children, who have unique vulnerabilities to pollution, may experience increased adverse respiratory health effects even at low concentrations. The prevalence of schools and childcare centres in industrial areas have increased in recent times, most probably due to the convenience factor and also increased hours of work for parents and carers. There are evidence which indicate children who study and live in industrial areas tend to have increased respiratory diseases / symptoms compared to children who don't live and study in industrial areas. Pollutants such as particulate matter, organic gases, inorganic gases and many more are generated within these areas amongst others. Aerosols (Particulate Matter (PM)) can be suspended in the air for long periods of time, depending on particle size and mass. The difficulty with PM is how these particles behave indoors and in the human body. If and when these particles become lodged in the lung tissue they cause serious respiratory illnesses.

In petrochemical plants the greatest potential source of particulate matter emissions to atmosphere is the unit for regeneration of the catalytic cracking catalyst. The gas exhaust heaters and boilers may also contain particles, but in much smaller amounts. The most common inorganic gaseous pollutants are ozone (O₃), nitrogen dioxide (NO₂) and sulfur dioxide (SO₂).

Exposure to nitrogen dioxide causes acute effects, principally low respiratory tract infections in children and increased airway responsiveness in asthmatics. The main source of NO₂ is combustion byproduct of high temperature processes. An example of atmospheric release is through vehicle traffic, but industrial emissions, such as from petrochemical plants, can also be considered an important source. SO₂ is emitted by several different sources to the atmosphere, but the most important ones are combustion processes and industrial sources. The combination of SO₂ with particulate matter can carry this pollutant deeply into the lungs, damaging delicate tissues.

The volatile organic compounds (VOCs) that are of interest for the purpose of this exam for indoor and out- door air qualities are benzene and toluene. These compounds, even in low concentrations, can be readily assimilated by the human body through the air causing health risks when exposure occurs for a long period of time.

The research team focused on analyzing and comparing the air quality of primary schools located near petrochemical plants and schools located in the urban area. Also, the possible sources of air pollutants were investigated along with the relationship between indoor and outdoor air qualities. In order to achieve this goal, mass concentrations, elemental concentration profiles and elemental associations of PM were determined. In addition, SO₂ and NO₂, were monitored in the schools, as well as personal exposure of the pupils both in the classroom and at home. It is important to notice that the houses of selected pupils were located near to their respective schools. The results from the study are summarized in Table 1 and Table 2.

School House Personal

SO₂

NO₂

Exposure

Indoor

(ppm3) Outdoor

(ppm) Indoor (ppm) (ppm)

Urban 2.83 4.55 3.57 2.20

Suburban 0.90 0.89 1.23 0.85

Urban 17.64 17.37 19.49 21.02

Suburban 8.56 8.03 9.00 10.22

Table 1: Average Concentration (ug/m³) of gaseous pollutants in urban and suburban areas

Benzene

Toluene

School House Personal Exposure

Indoor

(ppm) Outdoor

(ppm) Indoor

(ppm) (ppm)

Urban 2.8 1.4 1.5 2.3

Suburban 1.4 1.8 2.9 2.7

Urban 39 29 58 54

Suburban 48 42 17 15

Table 2: Overview of VOC concentrations (ppm) in urban and suburban areas