Healthy Development Measurement Toolkit

Indicator ES.4.b Proportion households living within 300 meters of major industrial stationary sources of air pollution

Data Source

Stationary source locations provided by the Bay Area Air Quality Management District (BAAQMD). Available upon request. Requested: Sept. 2007 http://www.baaqmd.gov/

Household data from Applied Geographic Solutions, Inc. Spring 2007 Update: Current Year Estimates. Methodology available at: http://www.appliedgeographic.com/library.html.

Map prepared by City and County of San Francisco, Department of Public Health, Environmental Health Section using ArcGIS software.

Table data is presented by planning neighborhood. While planning neighborhoods are larger geographic areas than census tracts, census tracts do not always lie completely within a planning neighborhood. SFDPH used ArcGIS software and a 'centroids within' methodology to convert census blocks to geographic mean center points. We then assigned census blocks to planning neighborhoods based on the spatial location of those geographic mean center points and calculated the planning neighborhood totals for the table. Detailed information regarding geographic units of analysis, their definitions, and their boundaries can be found in the HDMT at the following links:

http://www.thehdmt.org/etc/Geographic_Units_of_Analysis.pdf

http://www.thehdmt.org/data_map_methods.php

Explanation and Limitations

In 2005, the California Air Resource Board (CARB) issued guidelines in its Air Quality and Land Use Handbook for planners to avoid siting sensitive land uses in close proximity to stationary and mobile sources of air pollution. CARB defined sensitive land uses to include schools, park and playgrounds, day care centers, nursing homes, hospitals, and residences. The specific recommendations and protective distances are listed in the table below:

The map displays major industrial sources of air pollution in San Francisco along with the buffer zone recommended by the California Air Resouces Board (CARB) for each use. The map does not identify gasoline dispensing facilities or dry cleaners using perchloroethylene.

Source of Air Pollution	Air Resource's Board Recommendations
Freeways and High-Traffic Roads	Avoid siting sensitive land uses within 500 feet of a freeway, urban roads with 100,000 vehicles/day, or rural roads with 50,000 vehicles/day.
Distribution Centers	Avoid siting sensitive land uses within 1,000 feet of a distribution center (that accommodates more than 100 trucks per day, more than 40 trucks with operating TRUs per day, or where TRU unit operations exceed 300 hours per week). Take into account the configuration of existing distribution centers and avoid locating residences and other sensitive land uses near entry and exit points.
Rail Yards	Avoid siting sensitive land uses within 1,000 feet of a major service and maintenance rail yard. Within one mile of a rail yard, consider possible siting limitations and mitigation approaches.
Ports	Consider limitations on the siting of sensitive land uses immediately downwind of ports in the most heavily impacted zones. Consult with local air districts for the latest available data on health risks associated with port emissions.
Refineries	Avoid siting sensitive land uses immediately downwind of petroleum refineries. Work with local air districts to determine an appropriate separation.
Chrome Platers	Avoid siting sensitive land uses within 1,000 feet of a chrome plater.
Dry Cleaners Using Perchloro-ethylene	Avoid siting sensitive land uses within 300 feet of any dry cleaning operation. For large operations with two or more machines, provide 500 feet. Do not site sensitive land uses in the same building with perc dry cleaning operations.
Gasoline Dispensing Facilities	Avoid siting sensitive land uses within 300 feet of a large gas station (defined as a facility with a throughput of 3.6 million gallons per year or greater). A 50 foot separation is recommended for typical gas stations.

As noted by the CA Air Resources Board, "Emissions Are Not the Same as Exposure:... Emissions alone do not fully represent where and what extent of exposures to air pollution or possible health risks may occur. Weather and wind can result in exposures that occur in different locations from where the emissions actually occurred, and can create new pollutants due to chemical reactions in the atmosphere. Also, a larger number for emissions of a particular chemical may not be as important as smaller amounts of more potent chemicals. While air pollutant emissions information can serve as an indicator of local air pollution, it is the exposure to emissions that influences health effects.

Exposure is the amount of pollution that someone actually breathes or otherwise ingests at different locations. Exposure varies with how far away the source is, how the emissions are released into the air and dispersed by the wind, and in what locations a person spends their time doing various activities. Exposure to air pollutants can also occur from indoor sources such as cooking, cleaning, and smoking...

The importance of the exposure to health risk also depends on the combination of multiple air pollutants, the relative toxicity of the pollutants, and many other factors." For more information, visit: http://www.arb.ca.gov/ch/chapis1/chapis1.htm

Why is this a Community Health Indicator?

Evidence supporting sensitive use siting with regards to specific stationary sources is detailed in the California Air Resource Board (CARB) Air Quality and Land Use Handbook: A Community Health Perspective. Available at: http://www.arb.ca.gov/ch/landuse.htm

Motor vehicle emissions, power plants, and refineries are the predominant sources of fine particulate air pollution (PM2.5). Several large-scale studies demonstrate that increased exposure to PM2.5 is associated with detrimental cardiovascular outcomes, including increased risk of death from ischemic heart disease, higher blood pressure, and coronary artery calcification.^a