*Article* **A Hybrid Tool for Visual Pollution Assessment in Urban Environments**

### **Khydija Wakil 1,\*, Malik Asghar Naeem 1, Ghulam Abbas Anjum 2, Abdul Waheed 1, Muhammad Jamaluddin Thaheem 3, Muhammad Qadeer ul Hussnain 1 and Raheel Nawaz 4**


Received: 3 January 2019; Accepted: 24 February 2019; Published: 12 April 2019

**Abstract:** With increasing focus on more nuanced aspects of quality of life, the phenomenon of urban visual pollution has been progressively gaining attention from researchers and policy makers, especially in the developed world. However, the subjectivity and complexity of assessing visual pollution in urban settings remain a challenge, especially given the lack of robust and reliable methods for quantification of visual pollution. This paper presents a novel systematic approach for the development of a robust Visual Pollution Assessment (VPA) tool. A key feature of our methodology is explicit and systematic incorporation of expert and public opinion for listing and ranking Visual Pollution Objects (VPOs). Moreover, our methodology deploys established empirical complex decision-making techniques to address the challenge of subjectivity in weighting the impact of individual VPOs. The resultant VPA tool uses close-ended options to capture the presence and characteristics of various VPOs on a given node. Based on these inputs, it calculates a point based visual pollution scorecard for the observation point. The performance of the VPA tool has been extensively tested and verified at various locations in Pakistan. To the best of our knowledge, this is the first such tool, both in terms of quantitative robustness and broad coverage of VPOs. Our VPA tool will help regulators in assessing and charting visual pollution in a consistent and objective manner. It will also help policy makers by providing an empirical basis for gathering evidence; hence facilitating evidence-based and evidence-driven policy strategies, which are likely to have significant impact, especially in the developing countries.

**Keywords:** Visual Pollution Assessment (VPA); Visual Pollution Objects (VPOs); Analytical Hierarchy Process (AHP); urban visual pollution; urban areas; evidence based policy; urban planning

### **1. Introduction to Visual Pollution**

Recent decades have witnessed an exponential growth in urbanization demands, especially for improved governance in response to an ever-increasing urban complexity in a global and multi-level context [1]. In the developing countries, economic development, urban growth and dynamic economic transformation are accompanied by many other phenomena [2]. Usually, amenities are provided to the citizens without a well-managed plan of service provision; this results in the visual deterioration of the urban fabric. For example, marketing agencies install various kinds of outdoor advertisements

particularly hoardings and billboards, which in the absence of strict enforcement policies, often emerge as eye-sores and visual blights [3]. Similarly, provision of other services without strong managemen<sup>t</sup> result in solid waste dumps, cluttered hanging communication wires, encroachments, slums, bad road infrastructures, dilapidation of historical buildings, etc. Resultantly, urban life has come across as a disaster of aesthetic deterioration, transportation issues, air pollution, fumes, smog, and land and water pollution. However, in contrast to other types of pollutions, visual pollution has remained the most neglected aspect of urban life, both in policy and enforcement.

From the definitional evolution aspect, the term 'visual pollution' has been primarily recognized and researched in the mid of 20th century. Although earlier references to air and water pollution can still be found in the literature [4]. During the 19th century, recognition of types of pollution started from the laws on air and water pollution due to their harmful influences on the human environment. The era of the 1970s yielded a number of laws and treaties on 'noise pollution' that denotes the beginning of accepting other types of pollution. During the same period, the visual and light pollution was acknowledged in general, particularly in legal documents, and their managemen<sup>t</sup> was mandated to local authorities, state agencies, and municipalities [4].

Parallel to that, since the 1960s, visual pollution has been discussed in the developed part of the world resulting in the emergence of di fferent acts, rules and policies for the protection, preservation and enhancement of the urban visual environment [5]. A school of thought defined visual pollution as the type of pollution which o ffends human vision, spatial orientation, physical, mental health, or has psychological and economic e ffects on a community [6–8]. All those elements which a community finds unattractive, ugly, intrusive, disturbing come under visual pollution [9]. While, Nami et al and Jana describe visual pollution as "unbridled and uncoordinated diversity" of form, color, light, materials and accumulation of heterogeneous visual elements which make the manmade environment and urban landscape ugly and unattractive [3,7]. Chmielewski et al quote the term as compound and the resultant e ffect of "clutter, disorder and excess of various objects and graphics in urban landscape" [10]. Jurat ¯ e et al define visual pollution as "negative visual impact of Visual Pollution Object (VPO) on ˙ landscape" [11]. Additionally, the Supreme Court of the USA declared that "pollution is not limited to the air we breathe and the water we drink, it can equally o ffend the eye and ear" [12,13]. The scholars engaged in the visual impact assessments of natural landscapes have used the term visual pollution objects (VPOs) to refer to the physical components that have the ability to decrease the landscape's visual quality, may contribute to diminish visual significance, or may obstruct the view of valuable natural complexes [11]. A similar analogy is valid for urban visual pollution. In an urban context, we define the term 'VPOs' to refer to all the manmade features along with their physical characteristics (placement, appearance, size, color, view and functional hindrance etc.) that a ffect the visual quality of urban surroundings from a human's eye view.

Urban visual pollution is the negative physical condition of a number of objects which have a direct as well as an indirect relation with the quality of the built environment which ultimately has implications for humans living in that place [14–18]. It has been reported that visual pollution objects (together or individually) impact human health [19,20], distract drivers particularly along main highways [3,14,21,22], reduce property values, deface public places, spread annoyance, encourage needless consumption, or a ffect the identity of places [5,13,23]. It has been argued that better visual quality of a space has a relation to the safe and good behavior of residents and so as with better communities at a larger scale [24,25].

Furthermore, it is important to mention that the term visual pollution must not be confused with the concept of neighborhood disorder. As discussed earlier, visual pollution is the compound e ffect of disorder, excess of a number of physical elements while neighborhood disorder can be defined as "observed or perceived physical and social features of neighborhoods that may signal the breakdown of order and social control, and that can undermine the quality of life" [26]. The examples of neighborhood disorder may be adult loitering, drug dealing, crime, fighting in the streets and prostitution, and physical characteristics such as abandoned cars, dilapidated buildings, or litter in the streets [26,27]. Visual pollution is very much linked with the visual quality of public and community spaces [25] which includes regularity, order, beauty, symmetry, and simplicity, etc.

In previous studies, the subject of visual pollution has been explored from the dimensions of concept development, the listing of visual pollution objects and mitigation strategies [28]. However, the quantification and measurement have not been explored su fficiently. We have synthesized the previous work on the measurement of visual pollution and have provided a systematic approach to the development of a visual pollution assessment tool.

### **2. Approaches to Assessing Visual Pollution**

Although visual pollution is recognized as a type of pollution, most of the city governments find it hard to regulate it since they do not have any systematic way of quantifying its presence and measuring its level of intensity vis-a-vis its local impacts [10]. Various scholars have used di fferent techniques to measure visual pollution in their respective contexts, and at various scales ranging from a single street to a city. Table 1 presents a list of the relevant studies and highlights their respective scale, VPO coverage and methods.


**Table 1.** List of studies containing components similar to visual pollution assessment.

### *The Challenges of Measuring Visual Pollution*

It is evident from the literature review that the quantification of visual pollution at any point has always been challenging because of its subjective nature [28] and there doesn't seem to exist any standard set of guidelines for systematic assessment of visual pollution [7]. This further highlights the need for the development of a unified quantitative assessment tool. Although, researchers all around the globe have contributed to the assessment of visual pollution, they have had a certain set of limitations which are discussed below:

*Micro vs. Macro-level research:* Previous studies on visual pollution can be broadly categorized into two extremes of micro and macro scale. Some of the previous studies have on a small case study area like a commercial street, public buildings in a residential area, or a neighborhood with maybe one or two VPOs (billboards, commercial signs). In contrast, other groups of researches adopted a bigger working scale like a city, with multiple VPOs. Consequently, two (somewhat opposite) strategies with narrow and broad classes of indicators are found in the literature to assess the visual pollution of any area.

*Lack of quantification:* Since visual pollution is intrinsically sensitive, subjective and a complex type of pollution, no specific tool or instrument is available to measure the scale of visual pollution at any node [29].

*Dependency on subjective variables:* Most of the available research has used a mix of subjective and objective indicators where the proportion of subjective indicators has been considerably high. Hence, the results can be potentially influenced either by the respondent or the researchers' interpretation, expertise, interest and prevailing literature concepts. So, they may not be agreed upon or adopted in a di fferent context.

*Narrow coverage of VPOs:* Visual pollution has a broad area of knowledge of built and aesthetic environments comprising multiple objects. However, most previous work has focused on the measurement of visual pollution by means of single VPOs, which has resulted in single-object assessment approaches.

*The absence of structured tools:* Unlike other types of pollution, structured instruments and tools are not available for the measurement of visual pollution. Moreover, in some cases a combination of di fferent kinds of methodologies like public surveys [2,7], inter-visibility analysis, triangulation method, focus group discussions, photo comparisons [28,38], visual comparisons and experimentation, etc. [3] has been explored to assess a few (or often a single) VPO, which again indicates the need of a composite VPA tool. In most cases, statistical validity or reliability of the methods has not been assessed and discussed thoroughly.

From the above discussion, it is evident that there is a strong need to develop a comprehensive visual pollution assessment tool that can cover a wider variety of VPOs and can be used at various scales to calculate the visual pollution level at a certain point.

When it comes to subjective ranking and weighting, expert evaluation is preferred as they use their knowledge and experience for comparing objects or phenomena under study [39–41]. The relevant literature contains several weighing methods and techniques (e.g. Delphie method, ordering method [42–44]) that have experts evaluation at their core but possess respective pros and cons. In contrast, an Analytical Hierarchy Process (AHP) is considered comprehensive as it is a multi-criteria decision-making approach to deal with subjective and multiple conflicting criteria. The most prominent feature of the AHP method is the ability to compare both the quantitative and qualitative variables (verbal, graphics or numerical) on the same preference scale [45]. From the psychological point of view, it is also e fficient and consistent to compare two alternatives at a time rather than comparing them all at once. It is based on a ratio scale instead of an interval scale unlike other methods [27,45–47]. The other advantages of using AHP include its ability to handle multi-fold subjects, higher consistency among choices and the ability to evaluate the composite and compound scores of alternatives [48].
