The city of Watsonville is located on the southern edge of Santa Cruz County in what is known as the Pajaro Valley.  Watsonville has a population (51,703, 2008) that is primarily of Hispanic or Latino decent (75.1% in 2000) and covers an area of 6.6 square miles (1, 2).  Watsonville is home to the only regional airport within Santa Cruz County.  Built in 1942, the airport primarily serves private and corporate planes and houses 320 aircrafts (3) (see Attachment 1).  While airports serve as an important means of transportation for both people and commodities, they are also associated with adverse health effects due in part to air pollution (4). 

Air pollution has long been noted to contribute to asthma, cancer, cardiovascular and pulmonary disease (4, 5). Particularly susceptible are children exposed to high levels of outdoor air pollutants (6).  Individuals living within a 5 mile radius of major airports have been found to have increased hospital admissions due to respiratory conditions (7).  This correlation may be due to increased emissions from aircrafts and ground support – such as Carbon Monoxide, Sulfur Dioxide, Nitrous Dioxide, and particulate matter – associated with airports (8).

Watsonville Municipal Airport is located directly adjacent to a large health complex which houses Watsonville Community Hospital, Clinica del Valle del Pajaro (one of Salud’s community health centers), a center for diabetes education, and physician offices.  The terminal operates 9am-5pm, though the airport is open to private planes 24 hours a day, seven days a week.  The airport has its peak usage between 10am and 2pm .The airport averages 350 aircraft operations per day.

Air quality was monitored near the Watsonville Airport on two separate days in May 2009.  Two transects were conducted starting at the airport.  The first started at the airport near the health complex.  The second transect occurred at the airport near Green Valley Christian Elementary School (see Attachment 2).  The streets where measurements were taken are primarily residential and are indirectly in contact with the airport.  These measurements are intended to further evaluate a potential need for air quality monitoring.

Methods:

Using a GPS (to document location) and a Science scope logbook WL air quality monitor, measurements of Carbon Monoxide, Sulfur Dioxide and Nitrogen Dioxide were taken.  Air quality was measured on two separate days (May 12, 2009 and May 14th) taking 14 discrete data points along two separate transects near the Watsonville Municipal Airport.  Transects were 3000 ft long, and measurements were taken at 500 ft. intervals.  Readings took place on Nielson St leading toward Holm Rd, and on Loma Prieta Ave. heading towards Pennsylvania Dr.  Data was then uploaded to the Health and Environment Action Network (HEAN) website for further analysis.  Please see www.heanaction.org for maps and specific measurements.

Results:

The first measurement took place on May 12th at about 10am when the airport was just beginning its peak time.  Measurements on May 14th took place at 4:30pm when airport activity was higher.  Ranges for CO levels varied from 0.00 ppm to 1.7 ppm, SO2 from 0.00 ppm to 0.30 ppm, NO2 from 0.00 ppm to 0.035 ppm. Readings of the air quality around the airport indicate higher concentrations of carbon monoxide near the airport with a generally decreasing concentration as one moves away from the airport.  There are also pockets of slightly increasing carbon monoxide concentration near streets with higher traffic, such as South Green Valley Road and Holm Road. 

Discussion:

While there are few homes near the medical complex, patients coming in to the clinics and hospital for care may have increased sensitivity to reduced air quality.  With all the associated health hazards due to reduced air quality, we believe further studies near the hospital at peak airport activity times (for instance during the Watsonville Air Show in late May) and peak road-traffic times are warranted.  Furthermore, data from both the Salud Para La Gente Clinic and the Watsonville Community Hospital could be analyzed to determine numbers of patients visiting either center due to illness such as respiratory or cardiovascular disease.

Readings on May 12th were taken when few planes were circulating, and may have led to lower contamination readings.  It is likely that as more planes are operating, air quality worsens.  The range of carbon monoxide, sulfur dioxide and nitrogen oxide concentrations may also increase throughout the day due to increases in vehicular traffic. Although our findings are fit in the general pattern described in other studies (7), we need to increase our sample size in order to reach any valid conclusions.  Finally, noise contamination, though measured subjectively, appeared to be high during the afternoon measurements.

Aerial map of Watsonville Municipal Airport from 2002 Environmental Impact Report on http://www.watsonvilleairport.com/docs/deir.pdf

Area map
  

 

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