Air Quality in National City


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Four air quality course projects were completed by San Diego State University (SDSU) graduate students in collaboration with National City and the Sage Project in winter 2015. The intent of this partnership was to achieve the city’s goal to quantify fine particulate matter air pollution concentrations in residential, commercial, and industrial areas near roadways/freeways in National City. Professor Zohir Chowdhury was the instructor for Public Health 632, Air Quality, and designed studies relevant and appropriate to the hypothesized air quality issues which may arise in National City.

Students were trained on instrumentation, relevant software, and some statistical measures for data analysis. These four projects were carried out in a variety of sampling locations: industrial and residential areas, hot spots, parks, and the public library. This study included both spatial and temporal components of air pollution in National City.

Students working on all four projects sampled particulate matter of different sizes to compare with National Ambient Air Quality Standards (NAAQS) and World Health Organization (WHO) standards in order to check if they exceeded the standard levels. After sampling was done, the data collected by each group was analyzed and described. The results of these four projects are summarized in this report.

Across all of the experiments, it was observed that the level of particulate matter (PM) in the industrial area was higher than the residential area. This is due to PM emissions from industrial processes and car fuel combustion from the nearby highway, Interstate 5 (I–5), and large work trucks in the industrial area. Also, the PM2.5 concentration was found to be higher on the eastern side of the city, between the I–5 and Interstate 805 (I–805) freeways. Furthermore, the average PM2.5 concentrations were higher in the afternoon than in the morning, while the average black carbon concentrations were higher in the morning than in the afternoon. In addition to the aforementioned findings, the mean center park PM concentrations were found to be significantly different.

After sample collection, observation, and analysis, it was concluded that PM2.5 concentrations in National City met NAAQS and WHO regulatory standards. Although not exceeding the standards, there were stronger concentrations on weekdays during rush hour. In addition, although studies indicate that at high penetration rate, ultrafine particles have the capability of adverse health effects, there are no standards regulating its concentration and emission levels. However, measuring the presence in conjunction with analyzing public health statistics in the area may provide insight into the exposure of potential irritants affecting the population.

In addition to the results of these analyses, students provided varied mitigation strategies that could help improve air quality in National City and reduce the level of air pollutants. For instance, they recommend that the city employ stationary continuous monitoring stations to determine whether or not NAAQS regulations are being met. In addition, environmental policies could help to reduce PM concentration levels in vulnerable areas.

For example, restrictions could be placed on the construction of parks, schools, and public recreational facilities near freeways, and construction and roadwork could be limited to off–peak hours when children are attending school or otherwise less likely to be present in outdoor recreational areas. Using baghouses and electrostatic precipita-tors could also help reduce automobile emissions and minimize air pollution. Moreover, vegetation barriers, green roofs, and urban tree planting are other ways to improve air quality and sequester CO2. Sweeping or water flushing treatments are another recom-mended and effective method to reduce ambient PM2.5 concentrations. Finally, National City can participate in grant programs to incentivize California business owners to reduce emissions from stationary and mobile sources.

Read the final student report delivered to the local gov/community partner.

The Sage Project Contact Info
Kristofer Patron
Program Administrator
(619) 594-0103

University Faculty Contact
Zohir Chowdhury
Public Health

Local Government / Community Contact

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