Winthrop Community Health Survey

Winthrop Environmental Health Facts Subcommittee

(Winthrop Airport Hazards Committee)

Winthrop Board of Health

AIR

Brian Dumser, PhD, CIH

Chair of the Subcommittee

August 18, 1999

 

 

Summary

 

In many communities located close to major airports, power generation facilities, or other major industries, there is a strong perception that pollution generating activities at these facilities result in a direct negative impact on the health of residents.  Statements to this effect have been repeatedly voiced by representatives of the communities surrounding Logan airport, but, absent hard data in the existing record, no action has been taken by responsible authorities to investigate further.  Currently, plans are underway for the construction of additional facilities Logan airport which will markedly increase operational capacity and the generation of pollutants.  While potent arguments in favor of this expansion are being presented from an economic standpoint, once again no consideration is being given to the possible public health impact.

 

In light of the failure to address this issue by Massport, or by Federal or State regulatory authorities, the Winthrop Environmental Health Facts Subcommittee, a voluntary group made up of residents of the Town of Winthrop Massachusetts, elected to address the question directly.  A strong correlation is known to exist between exposure to petrochemical exhaust emissions and a variety of respiratory and cardiovascular diseases (1-10). Logan airport estimates its daily production of such pollutants at approximately 50,000 pounds per day (11). The Subcommittee undertook a survey to determine whether a correlation also exists between frequency and severity of respiratory disease and level of exposure to these pollutants as determined by location in Winthrop relative to the airport.

 

 The results of this survey demonstrate that a clear increase in several respiratory diseases and disease symptoms exists between areas of the Town which are adjacent to the airport, and those more distantly located on Broad Sound.  In fact, for the most common respiratory diseases, asthma and allergy, disease is twice as common in the most heavily exposed neighborhood as it is in the least exposed.  Finding no other likely explanation for this effect, the Subcommittee proposes that airport activities, most likely the generation of airborne pollution from the combustion of gasoline and kerosene, are indeed negatively affecting the health of the residents of Winthrop.

 

The implications of these findings are serious.  While the unique geography and demographics of Winthrop provided a situation where the effects of airport generated pollution could be studied in isolation from other pollutant sources, Winthrop is by no means the only community impacted, nor the community most highly impacted by airport activity-generated emissions. As sample size determines the sensitivity of the analysis, only the most frequently occurring respiratory diseases could be adequately tested.  Thus, while the case can be made strongly for asthma and allergenic disease, effects on other less common serious or life-threatening respiratory and cardiopulmonary conditions which are also linked to fuel exhaust exposure remain an unexplored possibility.  Finally,

while the study convincingly illustrates the difference in impact due to relative exposure level, it does not define a level of exposure where impact is minimal or tolerable.  In brief, the study demonstrates  that serious damage is being done to the health of the residents of Winthrop at current levels of airport activity, and this damage correlates with location, a measure of exposure to airport activity-generated pollution.  The Subcommittee feels it is incumbent on State regulatory authorities responsible for the public health to further investigate this matter, to further define the scope and severity of the problem, and initiate processes which will return our community to the state of health enjoyed by the majority of Massachusetts citizens.

 

Introduction

 

Winthrop is a peninsula which extends from East Boston south by south east to form the division between Broad Sound, on its eastern shore, and Boston Harbor on its western shore.  A portion of the western shore entirely encloses, and closely approaches Logan airport.  Winthrop is subjected to a variety of disturbances from the airport, including excessive noise and odors from burned and unburned fuel.  Although Logan carries out no air pollution monitoring in the surrounding communities, their published estimates from modeling studies indicate approximately 50,000 pounds of airborne pollutants are released daily, primarily from the combustion of Jet Fuel A.  Elsewhere it has been shown that a strong correlation exists between exposure to such pollutants and a variety of respiratory and cardiovascular diseases including lung cancer, chronic obstructive pulmonary disease, asthma and allergic rhinitis (1-10).  Individuals residing in communities surrounding Logan airport show a considerably higher incidence of these diseases compared to the statewide average (12-14).  It has not been possible to determine whether Logan airport activities contribute substantially to this health burden however, since the urban location of these communities presents a complex picture of pollution sources, including petrochemical pollution from power plants, industries, and heavy road traffic.

 

Winthrop, by contrast, is a stable, mature residential community without significant pollution sources except for the airport.  Despite this fact, asthma incidence in Winthrop closely mirrors that in the mainland communities which abut the airport, and lung cancer rates for females is 50% higher than the statewide average (14).  Some neighborhoods in Winthrop are located within a few hundred feet of major airport runways, while others are located as much as a mile and a half away.  Residents report a marked difference in perception of chemical odors from the airport in relation to location in the Town, indicating that different levels of exposure occur within the Town resulting from distance from the airport and wind direction.  In consideration of these facts, this study was conducted to determine whether any correlation exists between the level of exposure to air pollutants generated by airport activity and the incidence of and frequency of symptoms to respiratory disease.

 

Methods

 

The Town was divided into 10 neighborhoods, primarily on the basis of natural topography, containing between 1,000  and 2,500 residents each.  Two neighborhoods were selected as likely  representing areas of highest (#1, Court Road, and #2, Cottage Park), and lowest (#5, Winthrop Beach, and #6, Winthrop Highlands) exposure.  A questionnaire was devised, consisting of 30 questions to obtain information on the incidence of diagnosed asthma, allergies, chronic bronchitis, chronic sinusitis, and emphysema, and on the frequency of symptoms experienced.  Standard demographic information was also obtained on gender, age, and the duration of residence in the neighborhood.  A smoking history was obtained, and information on the frequency of perception of odors caused by airport-related activities.  Responses to questions on diagnosed disease incidence were yes/no, followed by a question on time since onset.  Responses to questions on symptom frequency included none and either 4 or 5 frequency ranges.

 

Interviews were conducted by volunteers from the community who were trained in requirements for objective data collection, chain-of-custody, and anonymity requirements.  Interviews were conducted 4 weekday evenings per week, between the hours of 6:30 and 8:30 PM.  Team leaders assigned streets to the interviewers.  Every residence in the neighborhood was approached, one time only, until the entire neighborhood was canvassed.  All residences, single and multiple family dwellings and apartment complexes were sampled, with the exception of mechanically ventilated buildings.  No commercial establishments were encountered in the zones polled. In this manner, a random sample of residents was polled which averaged approximately 18% of the population of the selected neighborhood.  The only exception to this was neighborhood 5, the last area sampled.  Activity was continued in this area, progressing from north to south, until the desired quota of 500 interviews each in low and high exposure areas was obtained.  Each questionnaire was identified only by neighborhood, and no names or addresses were collected.  The questionnaires were collected each evening and held centrally.

 

Following data entry, the database was screened to exclude unsuitable responses.  Corrections were made to the database where possible, for example intelligible but non-numerical responses.  Questionnaires with critical data missing or internally contradictory responses were excluded.  Data was also discarded for individuals residing in the identified zone for less than one year, or who were not in residence for at least four days per week.  All such changes were recorded.  Of the 1000 questionnaires obtained, 838 were admissible, 430 from the high-exposure zone (Area 1 - 172;  Area 2 - 258) and 408 from the low-exposure zone (Area 5 - 197;  Area 6 - 211).

 

In light of the seriousness of the effects on human health, and the truncated timetable presented by airport expansion activities, simplified exploratory statistical analyses were first carried out by excluding from the data all individuals not smoke-free for the past five years.  Data from high exposure (areas 1 and 2) and low exposure (areas 5 and 6) zones were pooled, and symptom frequency compared by chi-squared contingency analysis.  The results of this analysis formed the basis for an earlier report which was presented by the Caucus on Air Transportation to representatives of the state government July 1, 1999.

 

While that approach provided a convincing and statistically significant demonstration of the differential effect of location on disease incidence, the dataset contains more information which can be accessed by more sophisticated analyses.  To this end, the Subcommittee contracted the services of an epidemiological analytical firm, John Snow Inc., to further analyze the data.  SAS software was employed to re-incorporate smokers into the study, correcting for smoking history, age and sex by means of the Mantel-Haenszel Test.  Additional statistical analyses were performed with Epi Info V6 (15).  Further, it was noted that while low-exposure zones 5 and 6 were essentially equivalent, high exposure zones 1 and 2 showed a differential from one another which was consistent with position relative to the airport.  Contingency analysis was thus carried out for each of these zones separately, compared to the joined low-exposure population 5 and 6.  The complete set of statistical analyses, identification and criteria for data exclusion, complete and amended datasets, and original survey questionnaires are on file with the Winthrop Board of Health.

 

 

Results

 

Table 1.

Frequency of Odor Perception

% Response on Scale 0 - 100 (Days/Year)

 

 

 

Table 2.

Relative Risk

High Exposure Area 1 vs Pooled Low Exposure Zone (Areas 5 + 6)

Total Sample Size  - 580

           

 

 

Table 3.

Relative Risk

High Exposure Area 2 vs Pooled Low Exposure Zone (Areas 5 + 6)

Total Sample Size  - 666

 

           

**        Relative Risk is the proportionate increase (or decrease) in disease incidence in the high exposure area compared to the low exposure area, adjusted for influences due to the age, sex and smoking history as estimated by the Mantel-Haenszel procedure.

 

**        p value is the likelihood that the values obtained in the high and low exposure zones come from the same population and differences are due simply to random variation.

 

The results clearly show that a differential increase in respiratory disease occurs from the low exposure zones (area 5 and 6) through the moderately exposed area 2 to the highly exposed Court Road area 1.  The statistical significance is absent for the infrequent conditions chronic bronchitis and emphysema, though a positive trend is still evident.   Chronic sinusitis shows a strong correlation with the most highly exposed area.  For the more common diseases, allergies and asthma, statistical significance of the correlation with location is extremely strong both for the most highly exposed area 1 and for the more moderately exposed area 2.

 

Table 4.

Disease Incidence; Clinically Diagnosed, Self-Reported

Most Likely Estimate, 95% Confidence Limits

 

Area	Allergies	Asthma	Chronic Sinusitis
1	45.9 %  (38.3 % - 53.7 %)	22.7 % (16.6 % - 29.7 %)	23.3 %  (17.2 % - 30.3 %)
2	33.1 % (27.4 % - 39.2%)	16.3 % (12.0 % - 21.4 %)	18.7 % (14.1 % - 24.0 %)
5	27.4 % (21.3 % - 34.2 %)	13.7 % (9.2 % - 19.3 %)	18.8 % (13.6 % - 24.9 %)
6	32.2 % (26.0 % - 39.0 %)	13.7 % (9.4 % - 19.1 %)	15.6 % (11.0 % - 21.3 %)

 

 

Table 5.

Predicted Excess Disease in High Exposure Areas

 

 

 

Table 6.

Frequency of Respiratory Symptoms

% Response in Scale 0 - 100

 

 

 

Table 7.

Percent of Respondents Symptomatic At Any Level

Restricted Lung Function (Inhaler Use, Asthma Attack, Wheezing) and

Bronchonasal Irritation (Cough, Rhinitis)

 

Area	Restricted Lung Function	Bronchonasal Irritation