pollution is predicated to all tiny particles in the air which are produced due to human or natural activities ( 1 ) . since the centralization of human activities
is associated with metabolic human interactions in urban areas , different pollutants enter into air easily and cause the urban environment more vulnerable ( 2 ) .
it is such that , world health organization ( 1992 ) , has addressed the air pollution as a serious problem ( 3 ) .
improper use of fuel and inappropriate topography of tehran caused air pollution due to the entrance of approximately 1.5 million tons of pollutants annually .
hence , the combination of natural and artificial factorscauses tehran to be one of the most polluted cities inthe world , standing by mexico city , beijing , cairo , sao paulo , shanghai , jakarta , and bangkok ( 4 ) . air pollution has also caused painful events all around the world : the pollution event in meuse ( 1930 ) , in which 63 people experienced respiratory problems ; or the death of more than 400 people in london due to the contaminated thick smog in 1952 are two examples of such irrecoverable events ( 1 ) .
accor - ding to an environmental program of united nations 48 % of premature deaths are due to exposure to particulate matter in both outdoor and indoor environments , with potentially 500000 excess deaths annually due to particulate matter in outdoor situations ( 5 ) .
likewise , the air quality control agency s report indicates that more than 4500 people are dying every year in tehran due to air pollution ( 6 ) . the most important sources of air pollution can be divided into four key groups including overcrowding ( 7 ) , economic growth ( 8) , natural factors ( exp : geographical situation and topography , temperature inversion etc.)(9 ) , and mobile and stationary sources ( exp .
non - standards and poor fuel consumption of motor vehicles , industries in and around the city , home heating and cooling systems ) ( 1 , 10 ) . depending on the type and sources of pollutants , metropolises around the world took different measures to control the air pollution . among developing countries ,
south africa has benefited from a collection of best legal solutions in order to reduce the air pollution ; among them are objective and standard setting , status quo assessment and priority area delineation , control strategy preparation and implementation ( 11 ) .
china , as a developed country has also taken effective measures to control air pollution including integrated monitoring program on acidification of chinese terrestrial systems ( impacts ) , permanent control of vehicles emissions , increasing the quality of fuels , taking advantage of new technologies , developing transportation systems , providing five - year plans to understand causes and sources of pollution , current status , effects , and control of acid rain ( 1216 ) . in italy ,
special measures have been taken for energy management in industry , transportation systems and domestic systems ( 17 ) .
economic and industry growth plus overcrowding in india , caused city planners to take serious measures including banning polluting vehicles , developing roads , escalating standards and regulations enforcement and etc .
just some of them have been successful to decline air pollution , while the others failed to effectively and efficiently control air pollution . in south
africa , despite numerous plans and policies for controlling air pollution , they failed due to some major challenges such as lack of relationship between district and local municipalities , lack of relationship between provincial and local authorities , plan s integration , public s roles , technical capabilities in programs , extending a partial focus on some polluter sources and lack of systemic approach in air pollution planning , plans and climate change management , shortage of funding and etc.(11 ) . improper prioritization of environmental intervention , lack of funding , unwillingness of the countries to plan with a systemic approach , lack of enforcement and poor communication between all public and private sectors are the most principal factors causing the failure to successfully control air pollution ( 1821 ) . from 1334 , lots of case and cross - sectional
plans , programs and projects had been developed individually or as a part of a national document to control the air pollution of tehran .
they are including the first five - year development plan ( 19881993 ) , clean air plan ( 1995 ) , transportation emission reduction project ( 1997 ) , comprehensive plan of tehran s combating air pollution ( 1997 ) , second five - year development plan ( 19962000 ) , third five - year development plan ( 20012005 ) , 20 year visionary plan ( 2005 ) , forth five - year development plan ( 20062010 ) , tehran s master plan ( 2007 ) , fifth five - year development plan ( 20112015 ) and master plan of metropolises combating air pollution ( 2011 ) ( 22 ) . despite the fact that all these plans had been precisely codified , the present evidence implies that expected results based on reducing the air pollution have not been met due to lack of an integrated stewardship responsible for regulating , coordinating and monitoring the process and the gained results of air pollution control plans ( 23 ) .
hence it is necessary to analyze the air pollution controlling plans with a pathologic approach to identify a set of practical solutions for tehran .
this paper bears a twofold purpose : first , pathologically analyze air pollution control plans of tehran from the viewpoint of experts ; and secondly offer appropriate and effective solutions for controlling the air pollution .
a descriptive case study method was used in 2012 for pathologic analysis of air pollution control plans in order to offer solutions for tehran metropolis as the capital city of iran .
the research team provided a semi - comprehensive review of the literature which contained more than 70 articles of different metropolises all around the world for developing an initial conceptual framework as a springboard for developing the interview questions .
the scope of the review is limited to developed and developing metropolises ( china , italy , india and south africa ) which faced the same air pollution difficulties as in tehran . by developing the framework ,
a qualitative content analysis was drawn to identify the manifest and latent contents relating to different air pollutants and plans for their control .
the key contents around which the interview questions were organized consists of 1 ) causes and sources of air pollution , 2 ) challenges & obstacles towards effective performance of air pollution control plans and 3 ) the most effective controlling solutions for air pollution in metropolitan areas .
a semi - structured face - to - face interview was done to survey tehran s air pollution control plans , from the aspects mentioned above .
the participants were chosen by snow - balling sampling and according to their context of work ( practicing professionals and tehran , tarbiyat modarres and shahid beheshti university professors ) .
the interviews were continued until the saturation in data and no more information was gathered by interviewing and about 80% of data were repeated by experts , so about 14 experts , professors and managers interviews were practical and applied for data analysis .
the context of the interview consists of the extent to which air pollution control plans of iran are appropriate and the ways to cope with the air pollutants in different sectors ( industry , transportation systems and domestic system ) with regard to other metropolises experience in the very same field .
in addition , they were asked to provide more information about the relevant issues , if possible .
as the interview sessions precede , the quality , relevancy and comprehensiveness of questions were developed simultaneously .
all the opinions ( meaning units ) were reviewed , condensed and labeled as a code through a back and forth movement between the whole and part of the interview texts .
then the codes with the same meaning grouped together under higher order heading to create categories ( 27 sub - categories and 8 categories ) in a way that each group of codes dealt with a specific issue or content area .
next , the primitive title and content of all categories and sub - categories were discussed by the article research team .
finally , the underlying meanings which were the latent contents of the categories were formulated into four main themes .
the analysis results of all 14 viewpoints from practicing professionals were categorized into four main themes .
the first theme is demonstrated in table 1 as  causes and sources of air pollution of tehran metropolis  . as it is depicted in the table
, the most vital sources of air pollution corresponds to the process of policy making , lack of attention to environmental changes , topogherafic status of tehran , pollutant due to mobile and stationary sources and the matter of improper energy management .
the second theme is demonstrated in table 2 as  challenges & obstacles towards effective performance of air pollution control plans of tehran metropolis  .
causes and sources of air pollution of tehran metropolis challenges & obstacles towards effective performance of air pollution control plans of tehran metropolis as it is shown , the most important challenges of tehran s air pollution management are focused on nine areas which we abstracted them into two wider categories including firstly , air pollution stewardship challenges and secondly , environmental ( political , economic , social and technical ) challenges .
some factors such as lack of information for evidence - base decision making , poor vertical and horizontal coordination among urban developmental goals and plans , improper funding , follo - wing unfit pattern and mores are categorized as stewardship challenges , on the other hand political intervention in plans provision and performance , sanctions against iran , unaffordability of some families to exchange their non - standard cars with new ones and some more are identified as environmental challenges , which are presented in the table 2 in detail . in order to demonstrate the challenges importance , the amount of their repetitions were accounted and shown in table 3 in percentage : the third theme is demonstrated in table 4 as  the most effective controlling solutions for air pollution in the metropolitan areas  . with regard to the fact that air pollution is one of national planning priorities in metropolitan areas ,
the most effective controlling solutions for air pollution in the world the forth theme is demonstrated in table 5 as  the most effective controlling alternatives for air pollution in tehran metropolis  which is broken into two main categories , first of all technical & infrastructural factors , then managerial & administrative factors .
planning based on reliable evidences , involving all responsible key stakeholders in planning process , developing the parks & green sites , monitoring the amount & type of different pollutant in the air by the help of new technology , fair distribution of facilities and development , non - individual based planning , considering the implementation & monitoring capacities in contemporary with planning , improving the mutual understanding and communication among authorities and citizens , considering revision loops for plan , developing environmental standards and mores are categorized as technical and infrastructural factors .
furthermore , improving the cooperative & mutual communications among the education deputy of tehran municipality and the other authorities forculturalization & informing , developing public participation capacities , are categorized as managerial & administrative factors .
tables 5 , there are those alternatives which suites to tehran s status and were mentioned by the interviewees . in order to estimate the alternatives importance , the amount of their repetitions were accounted and shown in table 6 in percentage .
the most effective controlling alternatives for air pollution in tehran metropolis the priorities of most effective controlling alternatives for air pollution in tehran metropolis
our findings confirm that tehran s air pollution has been due to five major reasons including improper policy making , no attention to the pollutants changes , geographical situation , mobile and stationary sources and nonstandard energy production .
paying inadequate and incoherent attention to the sources of pollution caused the authorities face with some important challenges including those which could be due to not having a unique and organized stewardship and of course those challenges could be due to the environmental changes which are not controllable by the air pollution management authorities . as all metropolises confront such challenges , their authorities implement different plans in order to manage air pollution .
some of the best and effective controlling solutions are focused on culturalization , infrastructural development such as public transportation ( 16 ) and applying economical control levers in china ( 13 ) , utilizing participatory capacities and strategic planning in south africa ( 11 ) , applying solar battery to produce clean energy in italy ( 24 ) , identifying emission limits for automobiles and industry in india ( 3 ) . in iran , same as other metropolises , several plans are prepared and some are implemented , but , unfortunately , thanks to some challenges mentioned above , they failed to control tehran s air pollution as it was expected to be achieved in the plans . to solve the challenges and improve the quality and effectiveness of controlling air pollution plans ,
should name paying more attention to the matter of stewardship in the field of air pollution management , cultural and infrastructural development , focusing on effective management system doing systematic studies before planning in other words systematizing the plan preparation process , standardization of fuel and energy production and consumption , enhancing public participation capacity , developing appropriate coordination and controlling mechanism , realization of social justice through capacity evaluation in regional scope , standardizing and utilizing new technologies and professional experts , stopping manufacture of the low quality automobiles and reducing import tariff of the high quality ones , applying economical control levers , making transparency in deaths statistic due to air pollution , providing environment organization s box to centralize polluting industries penalties , and legitimizing air pollution control plans to enhance their implementation s guarantee ( 22 ) .
our findings about the air pollution control plans challenges replicate the finding of a survey on controlling air pollution plans in south africa conducted by niaiker et al .
( 11 ) . in the viewpoint of niaiker poor standards and regulations to support plans implementation , poor cooperation among stakeholders ( key authorities , planners , policymakers , citizens etc . ) , poor resource generation and poor attention to the type and source of pollution are the most important challenges caused the failure of control plans .
also , asadollah ( 23 ) mentions that poor and disorganized stewardship is a key factor which leads to the failure of tehran s air pollution control plan . furthermore , our finding about controlling alternatives for tehran s air pollution is similar to the findings of a survey on the same subject in this metropolis ( 19 ) .
he believed that developing an appropriate evaluation and monitoring mechanism to enforce different responsible authorities through evaluate the performance of them , realization of social justice and improving the participation capacities are success factors of plan implementation .
these finding can help tehran s authorities to look at plan preparation process with a new approach and would be practical for every developing large cities which are confronting such problems . in other words , authorities can positively benefit the viewpoints of the practicing professionals who consider the plan s deficiencies from unlike aspects in diverse levels of initials in advanced studies requirements , plan s preparation to plans implementation .
we considered only the most important challenges of tehran s air pollution control plans in order to offer effective controlling solutions .
further , more researches should be done to determine priority of the offered solutions in accordance with tehran s facilities and requirements .
controlling air pollution of tehran needs a serious attention from policymakers to make an effectual enforcement through applying a systemic cycle of preparation and revising effective and comprehensive plans , implementing enforcement and evaluating the environmental impact of the plans through involving all stakeholders
ethical issues ( including plagiarism , informed consent , misconduct , data fabrication and/or falsification , double publication and/or submission redundancy , etc . ) have been completely observed by the authors .
 abstractbackgroundthe centralization of human activities is associated with different pollutants which enter into environment easily and cause the urban environment more vulnerable . regarding the importance of air pollution issue for tehran metropolis , many plans and regulations have been developed . however , most of them failed to decline the pollution . 
 the purpose of this study was to pathologically analyze air - pollution control plans to offer effective solutions for tehran metropolis.methodsa qualitative content analysis in addition to a semi - structured interview with 14 practicing professional were used to identify 1 ) key sources of tehran s air pollution , 2 ) recognize challenges towards effective performance of pertinent plans and 3 ) , offer effective solutions.resultsrelated challenges to air - pollution control plans can be divided into two major categories including lack of integrated and organized stewardship and pest challenges.conclusionfor controlling the air pollution of tehran effectively , various controlling alternatives were identified as systematization of plan preparation process , standardization and utilization of new technologies & experts , infrastructural development , realization of social justice , developing coordination mechanisms , improving citizens participatory capacity and focusing on effective management of fuel and energy.controlling air pollution in tehran needs a serious attention of policymakers to make enforcements through applying a systemic cycle of preparation comprehensive plans . 
 further , implement the enforcements and evaluate the environmental impact of the plans through involving all stakeholders . 
Introduction
Materials & Methods
Results
Discussion
Conclusion
Ethical consideration