| Course | MPH 506 Environmental Health in Public Health |
|---|---|
| Week | 3 |
| Paper type | Exposure pathway analysis |
| Length | About 1,120 words, 5 pages |
| Format | APA 7 student paper |
| School | Chamberlain University |
| Program | Master of Public Health (MPH) |
| Updated | October 2026 |
Free sample paper for MPH 506 Week 3
Exposure Pathway Analysis: From the Harmon Field Run-Up Pad to the Hands of Children Under Six in Eastgate, Link by Link
Student Name
Chamberlain University
MPH 506: Environmental Health in Public Health
Instructor Name
Month Day, Year
Exposure Pathway Analysis: From the Harmon Field Run-Up Pad to the Hands of Children Under Six in Eastgate, Link by Link
Purpose
This analysis asks whether lead from the small planes using Harmon Field, the Brennan County airfield introduced in week 1, reaches young children in the neighboring Eastgate area. It works through the five parts of a pathway in order: where the lead starts, what carries it, where people come into contact with it, how it gets inside them and who those people are. Each link is graded as complete, potential or incomplete, with the evidence for the grade. A pathway is complete only if every link is; a single broken link means no exposure through that path, however toxic the agent.
Link 1: The Source
The source is not the airport as a whole but particular places where engines run at high power while the aircraft is stationary or slow. At Harmon Field, the largest is the run-up pad at the east end of Runway 27, used before most departures under the prevailing west wind. Secondary sources are the takeoff roll and the first climb. The county's fuel records show sales of about 210,000 gallons of 100LL in 2025, nearly all to piston aircraft, and the tower logged about 86,000 piston operations, more than half by the two flight schools. Air modeling for small airfields places the peak concentrations around the run-up area, where engines run hard for a minute or more in one spot (Carr et al., 2011).
Grade: complete. Leaded fuel is sold and burned on site, and the run-up area is known.
Two other sources on the field were considered and set aside. Fueling at the self-service pump releases vapor, which matters for line staff but not for homes 300 meters away. Engine maintenance in the hangars produces small amounts of waste oil containing lead, which is handled through the county's hazardous waste contract.
Link 2: The Medium and Its Transport
Lead leaves the exhaust as fine particles in air. Some remain suspended and travel with the wind; others settle within a few hundred meters. Under the prevailing westerly wind, the plume from the run-up pad moves toward Eastgate. Settled lead then becomes part of a second medium, soil and dust, which can be carried indoors on shoes and by pets.
Evidence for this link is partial. The county ran a single air monitor at the airport fence for twelve months in 2025, which recorded a maximum rolling three-month lead average of 0.09 micrograms per cubic meter, below the national standard of 0.15 but far above typical urban background. There is no monitor inside the neighborhood. In spring 2026, the county collected composite surface soil samples from 30 yards. Yards within 400 meters of the pad had a median of 140 parts per million, compared with 60 parts per million in yards more than 1,200 meters away. These are composite course figures, but they show the pattern the pathway predicts.
Grade: complete for air near the fence; potential for air within the neighborhood; complete for soil, with the caveat that soil lead cannot be attributed to aircraft alone.
Link 3: The Exposure Point
An exposure point requires evidence that people are actually present where the agent is. Three points qualify. Backyards in the first two blocks east of the airport fence are where young children play daily. The playground at Lindgren Elementary, about 600 meters east, is used by 410 students, including preschoolers in a district program. The common play area of the Eastgate mobile home park, 350 meters from the pad, is bare soil.
A walk-through in April 2026 found children playing in yards and in the mobile home park during the afternoon. The school's recess schedule places children outdoors during the busiest flight school hours, from late morning to early afternoon.
Grade: complete for yards and the mobile home park; complete for the school playground.
Link 4: The Route of Entry
Two routes carry lead into children's bodies. Ingestion is the main one: children under six put hands, toys and objects in their mouths, swallowing soil and dust many times a day. Inhalation contributes near the fence and during busy periods, but drops off quickly with distance. Skin contact is a negligible route for inorganic lead.
Grade: complete for ingestion; potential for inhalation in the neighborhood.
Link 5: The Receptor Population
The receptor population is about 240 children under six living in Eastgate, plus the preschool and lower grades at Lindgren Elementary. Many live in housing built before 1950, which almost certainly contains lead paint, and the mobile home park has a high share of families with low incomes, in which iron deficiency is more common. Evidence from other airports supports this receptor: children within 500 meters of airports serving leaded fuel had higher blood lead than other children in North Carolina (Miranda et al., 2011), and a California study tied children's blood lead to distance from the runway, wind direction and the number of piston flights (Zahran et al., 2023). The county has blood lead results for Eastgate children only from routine Medicaid screening, which covered fewer than half of eligible children in 2025.
Grade: complete as a population present and susceptible; not yet confirmed by local blood lead data.
Table 1
Exposure Pathway Links From the Harmon Field Run-Up Pad to Eastgate Children
| Link | Evidence | Grade |
|---|---|---|
| Source: run-up pad, takeoff | Fuel sales, operations count, known run-up location | Complete |
| Medium: air | Fence monitor; no neighborhood monitor | Complete at fence, potential in neighborhood |
| Medium: soil and dust | Soil gradient with distance from the pad | Complete, source attribution uncertain |
| Exposure point | Children observed in yards, park and school playground | Complete |
| Route | Hand-to-mouth ingestion; inhalation near fence | Complete for ingestion, potential for inhalation |
| Receptor | About 240 children under six plus school | Complete, local blood data incomplete |
Note. Note. Monitoring and soil figures are composite values constructed for this course.
Overall Judgment
The soil and dust ingestion pathway from the run-up pad to children in Eastgate is complete. The air inhalation pathway is complete near the fence and potential further into the neighborhood. The main uncertainty is not whether the pathway exists but how much of the children's lead comes through it rather than from old house paint. Three steps would narrow that uncertainty: an air monitor inside the neighborhood, isotope ratio analysis of a subset of soil and dust samples, and outreach to raise blood lead testing of Eastgate children under six.
References
Carr, E., Lee, M., Marin, K., Holder, C., Hoyer, M., Pedde, M., Cook, R., & Touma, J. (2011). Development and evaluation of an air quality modeling approach to assess near-field impacts of lead emissions from piston-engine aircraft operating on leaded aviation gasoline. Atmospheric Environment, 45(32), 5795-5804. https://doi.org/10.1016/j.atmosenv.2011.07.017
Miranda, M. L., Anthopolos, R., & Hastings, D. (2011). A geospatial analysis of the effects of aviation gasoline on childhood blood lead levels. Environmental Health Perspectives, 119(10), 1513-1516. https://doi.org/10.1289/ehp.1003231
Zahran, S., Keyes, C., & Lanphear, B. (2023). Leaded aviation gasoline exposure risk and child blood lead levels. PNAS Nexus, 2(1), Article pgac285. https://doi.org/10.1093/pnasnexus/pgac285
Reading the MPH 506 Week 3 instructions
The third week asks you to analyze an exposure pathway for the hazard you have been studying. Identify the source precisely, not as a whole facility. Describe the medium that carries the agent and how it is transported. Establish the exposure point with evidence that people are actually present there. Name the route of entry and why it matters for dose. Describe the receptor population, including its size and susceptibility. Grade each link as complete, potential or incomplete, and explain the grade. The central task is to show how the agent gets from source to people, so do not jump from contamination to health effects without the links in between, and cite your evidence for every link.
How the MPH 506 Week 3 example is put together
The sample places the source at the airfield's run-up pad and takeoff roll, supported by fuel sales and operations counts, and sets aside two other on-field sources with reasons. Air and then soil are the media, with a fence monitor reading and a soil gradient from near to far yards. Exposure points are backyards, a mobile home park's bare play area and a school playground, confirmed by observation. Ingestion is the main route, inhalation potential. About 240 children under six are the receptors, with blood lead testing too sparse to confirm the last link locally. A table grades every link, and the conclusion calls the soil and dust pathway complete and the air pathway partly so.
Reading the MPH 506 Week 3 grading rubric
The heaviest loss in a pathway analysis is the jump: contamination is shown, health effects are described and nothing connects them. Rubrics test for that gap directly. Assuming people are present at an exposure point without evidence is a second common weakness. Omitting the route, so dose cannot be reasoned about, also costs points, as does treating transport as obvious. Analyses that grade the whole pathway as complete without examining each link lose much of the judgment mark. Strong papers name a specific source, describe transport, show that people are present, state the route, describe the receptors and grade each link with evidence, ending on what would resolve the uncertain ones.
MPH 506 Week 3 help: mistakes that cost points
Pathway analysis is where many students first see how much evidence an environmental claim needs. If you share your hazard and setting, we can help you find a precise source, look for monitoring or sampling data for each medium and decide how to show that people are present at the exposure point. We can also help you grade each link honestly and plan what would strengthen the weak ones. The setting and every grade you assign stay yours. Where a section uses an agency's pathway table format, send it and the custom sample will use the same columns and grade labels.
Get a MPH-506 Week 3 example written to your instructions
Send the Week 3 instructions with the framework your section uses and the scenario it supplies, and a custom example is written to that structure and returned inside 24 to 48 hours. The first one is free. Which links you judge complete stays your call to defend.
More MPH 506 papers and MPH samples
- MPH 506 Week 1: Located Hazard Post
- MPH 506 Week 2: Environmental Hazard Analysis
- MPH 506 Week 4: Risk Assessment Write-up
- MPH 506 Week 5: Case Study Analysis
- MPH 506 Week 6: Community Environmental Assessment
- MPH 506 Week 7: Risk Communication Plan
- MPH 506 Week 8: Policy Brief
- MPH 505 Week 3: Audience Analysis
- MPH 504 Week 3: Disease Burden Analysis
- MPH 503 Week 3: Legal Authority Write-Up
- MPH 500 Week 3: Agency Profile
MPH 506 Week 3 questions, answered
What makes a pathway incomplete?
Any missing link. A contaminated aquifer nobody draws from, a soil hazard on land nobody enters, a substance present in a form that cannot be inhaled or absorbed. Incomplete pathways matter because they identify where a control already works, and saying a pathway is incomplete for a stated reason is a finding rather than a failure to find one.
How do I establish the exposure point?
With evidence that people are actually there: residential proximity, a water source in use, a subsistence practice, an occupational task. Assuming presence is the commonest shortcut in these analyses. Where you cannot establish it, mark the link as potential and say what would confirm it, which is what a real assessment would do.
Can one source have several pathways?
Frequently, and covering them separately is usually expected. A release may reach one group through drinking water and another through fish consumption, with quite different doses and different susceptible populations. Analyzing them as one blurred pathway loses the distinctions that any control decision would have to rest on.
Where can I find a free MPH 506 Week 3 sample paper?
The full MPH 506 Week 3 pathway analysis, grading each link from an airfield run-up pad to young children nearby, is on this page.
Which link does the MPH 506 Week 3 sample leave unconfirmed?
The receptor link is complete as a population present and susceptible, but local blood lead data are too sparse to confirm it.