One notion of safety that we often fail to consider is the idea of pollution. However, the presence of pollution in a community can be a strong deterrent to a walkable community. Pollution can take many forms including air, solids, and noise. In our communities, pollution typically manifest by way of vehicle and or industry exhaust, litter and or chemicals on the ground, and excessive noise from too much traffic and or inconsiderate community members.

For many people, signs of pollution equate with issues of safety. For example, I used to have a neighbor who would come home from work, change into her running gear, get her dog and drive away. Curious, one day I asked her where she goes. She said that she goes to a neighboring community to run with her dog. Not being a runner, I asked how come she didn’t run in our community. She said that there were too many noisy commercial vehicles and buses that scared her dog, she was tired of breathing in the diesel exhaust, and that there was too much broken glass on the streets. In other words, she was afraid the noise stressed her dog, she was afraid of the long-term effects of breathing vehicle exhaust, and she was afraid that either she or her dog might get hurt from the broken glass.

Air pollution that detracts people from a community generally has some aroma or can be visible by the naked eye. A couple of studies have shown that foul-smelling pollutants negatively affected mood and attraction. This research also showed that foul-smelling pollutants facilitate more aggression. Others studies have shown that the level of air pollution correlated with the level of domestic abuse and psychiatric disturbances. What this means is that communities with high levels of air pollution will most likely have lower levels of pedestrian activity.

For most communities, the source of air pollution comes from vehicle traffic, diesel trucks and buses in particular. To rectify this problem communities may want to consider either banning cargo trucks from the commercial areas, which is probably not feasible, or limiting the hours that cargo vehicles can make their deliveries and or operate along commercial corridors. Many communities have adopted this position and have thus limited the use of commercial vehicles to the early morning hours of (7am-10am). These are generally standard business hours for delivery personnel and times in which few pedestrians occupy the streets.

Another solution to help reduce the level of air pollution is the incorporation of green spaces. Trees and grass, as a natural function, absorb carbon monoxide and release oxygen as a by-product. Ergo, small park-like areas with trees, grass, and benches amongst the commercial area would increase the pedestrian use of the area.

Likewise, physical pollution by way of litter and/or liquid spills is also a detractor to pedestrian activity. Litter, to many people, indicates a lack of social order, which is a strong deterrent to pedestrians. Because litter tends to accumulate or derive from places where people generally wait such as traffic lights and bus stops, ample bins should be provided in these areas. What I mean by ample is that there should be enough bins with sufficient capacity to handle the rubbish generated from day to day. Another aspect of litter that can be dealt with relatively easily is the smaller particles found along the edges of streets (cigarette butts, broken glass, and candy wrappers). Routine and regular street sweeping during the early morning hours can effectively deal with this issue. The last aspect of physical pollution to be discussed here are the spills generated from automobiles that leak oil, antifreeze, and/or other liquids. At some level, people compare the level of these pollutants on the road with other communities. Some may notice because of the slippery nature of the chemicals, others might notice because of a pet, and still others might notice because of the unsightliness of the blotches. Again, this can be easily dealt with by routinely cleaning the streets.

Noise is one of the most dissatisfying features of a community and has the greatest impact on pedestrian activity. How much noise effects pedestrians is directly related to the motivation of the noisemaker, the degree of perceived control over the noise, and how avoidable the noise appears to be.

Noise, in the mind of most people, is an incompatible sound that lacks consistency in volume and pitch, and infringes upon normal conversational patterns. Sources of noise in our commercial areas derive from heavy vehicles such as cargo trucks and busses, excessive music volume coming from storefronts, and the by-product of construction equipment. When we look at how noise affects pedestrian behaviors, we see that the first line of defense is to avoid the situation.

Studies show that when we cannot avoid the noise that we will increase our pace and become more focused in our stride. The primary goal is to escape the noise. This means that we will not be looking in the store fronts, will not be lingering to use the communities' features, and will probably avoid the area once we deem the source of the noise to be chronic as opposed to a single episode.

This latter concept of chronic versus episodic is an important concept for pedestrian friendly communities. Pedestrians often forgive noise derived from construction work because most view it as being temporary, noise coming from heavy vehicles and storefronts, on the other hand, tend to detract pedestrian activity because this is noise that is deemed chronic.

This idea places many communities in conflict. On the one hand, buses transport people into the commercial areas, but on the other hand, they tend to be noisy. So, the quandary of many communities is how to incorporate buses while keeping the noise level down. Some communities have opted to rotate the buses along periphery streets so that they are not on the direct commercial street, and their concentration isn’t all on one street, but varied along other streets. This action decreases the perception of the noise being chronic on any one street, especially the main commercial street.

Another great solution for cutting down the noise level goes back to the vegetated median and tree-lined streets. Since most community areas have a great deal of glass and masonry, sound reverberates along the corridor making the area seem louder than necessary. A vegetated median along with trees will help to absorb sound, thereby decreasing the reverberation and/or decibel levels.

Communities have made leaps and strides in decreasing the levels of air, solid, and noise pollution. We now have many city vehicles that operate on natural gas or are electrically run, and many streets that are now being actively cleaned on a regular basis.

Additionally, many cities are seeing the value of green spaces as a means of helping to reduce air and noise pollution, and many communities have already limited the hours in which commercial vehicles can operate on community streets.

However, other communities haven’t been able to make quite as much progress, which is unfortunate because of all the issues discussed with regard to safety, pollution is perhaps the easiest to address. In simple terms, if two people are able to walk along the sidewalk while carrying on a conversation at a normal voice level, without having to watch where they walk, and without smelling a fowl odors you can be relatively confident that pollution is not a factor affecting the walkability of your community.

Published: August 18, 2003

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David Alan Kopec "DAK" has a Ph.D. in Environmental Psychology with a concentration in perception and design and two master's degrees, one in Architecture and another in Community Psychology. He also has a bachelor's degree in community/public health, is certified by the National Commission for Health Education Credentialing (NCHEC), a member of Interior Design Education Council (IDEC), and studied the practice and principles of Feng Shui in China. Among DAK's most notable accomplishments include the completion of the first textbook on environmental psychology for design, published by Fairchild Books, which won ASID's 2006 Joel Polsky Prize. He has also authored two monographs; the first analyzes the Americans with Disabilities Act along with the common issues faced by an elderly population, published by ASID. The second monograph discusses the design of long-term care facilities in a multicultural society. This is being published by NCIDQ. Currently DAK is working on a second textbook that analyzes health, sustainability and design. Fairchild Books will release this book in the Spring of 2008. Also, DAK is a 2006 award recipient from Rebuilding Together San Diego. DAK is an Associate Professor of Design at the Newschool of Architecture and Design. In addition, DAK has a private practice, provides consulting services and educational lectures at events such as Neo-Con World’s Trade Fair in Chicago, the annual leadership conference for the American Society for Interior Designers (ASID), and dozens of physician conferences and meetings.