An investigation of air quality surrounding Lake Merritt in Oakland, California

Iskander Ararso, Nicole Casino, Bai Chen, Jasmine Johnson, Krystal White-Koerber, Stephanie Lau, Victoria Truisi, Margarito Yanez, Anna Yeung, Miguel Unigarro, Gail Vue, LaKisha Garduño and Kevin Cuff

Lake Merritt is a naturally occurring inlet from the San Francisco Bay that was converted into an urban lake near downtown Oakland in 1860. The Lake itself is located within the Lake Merritt Park and Wildlife Refuge, home to over 90 species of migrating waterfowl, as well as a variety of aquatic wildlife. Its close proximity to downtown, several busy roads, and two major highways makes Lake Merritt a popular destination that is easily accessible to Oakland residents, but also puts it at risk for impaired air quality due to automobile exhaust. In an effort to assess air quality near Lake Merritt, we measured percent oxygen and carbon dioxide (CO2) concentrations in ambient air. These two gases can be used to assess air quality because the significant build up of CO2, which primarily results from the incomplete combustion of personal automobile engines, can result in the reduction of oxygen to concentration levels that are hazardous to human and other life. During the Summer of 2005, air samples from over 90 different locations were collected and used to make these measurements. Measurements were made with PASCO data-loggers attached to sensors that use infrared detectors to measure the amount of energy absorbed by carbon dioxide and oxygen molecules. Results were statistically analyzed, mapped, and used to assess the overall quality of air surrounding the Lake. Preliminary analysis of oxygen data indicates that higher concentration levels occur near sections of the Lake that are furthest removed from major roads, as well as in areas that have significant amounts of vegetation. In fact, the highest value recorded in this study was measured in a sample obtained near a grove of trees in a portion of the park that has the most vegetation, and that is furthest removed from major roads. Air quality here is high primarily due to the absence of CO2 build up associated with automobile traffic. The lowest values recorded were measured in samples collected along a stretch of the lakeshore that is very close to one of the busiest streets in the general area. The general trend of carbon dioxide concentration levels was also observed to decrease with distance from major roads and nearby highways. In the future, we plan to investigate possible relationships between oxygen and carbon dioxide concentrations in air surrounding the Lake and dissolved oxygen concentration of its waters. To the best of our knowledge, the air quality surrounding Lake Merritt has not been investigated before. Therefore results obtained during this study provide the foundation upon which future research may be built.