Introduction: According to the statistics of the World Bank, the amount of carbon dioxide emissions in Iran has grown by 210.65% in the last thirty years. In such a situation, this unfavorable situation should be changed in line with environmental standards, which naturally requires the identification of important factors affecting pollution. The main purpose of this research is to investigate the factors that seem to affect pollution according to the background. As economic complexity improves, higher knowledge and technological progress can lead to less polluting activities. Reducing economic risk and consequently increasing investment, if it is followed by efficient use of inputs and the use of environmental technology, can reduce pollution by overcoming the effect of scale. Higher energy prices, energy-efficient technologies and low energy prices have imposed technologies with a higher share of energy input on companies, which has an impact on the environment. The impact of trade expansion on pollution depends on the results of scale, combination and technical effects. ICT can change the efficiency of energy consumption by moving the economy towards a knowledge-based structure, by substituting information for energy, and thus affect pollution. Urban density can reduce energy consumption by creating economies of scale for public urban infrastructure, while the absence of proper urban infrastructure has the opposite effect. FDI increases relative advantage in which production sector affects pollution. Also, the advanced technology that comes with FDI affects the environment.
Materials and Methods: Explanatory variables of the model are economic complexity, interrelationship between economic risk and investment, interrelationship between energy price and energy intensity, trade liberalization, internet users, capital per capita, foreign direct investment and urbanization rate and the dependent variable of carbon dioxide emissions. The information of the variables was obtained from the World Bank, the MIT University website, and the International Country Risk Guide (ICRG) database and the energy balance sheet. The investigated period was during 2000-2022 and the ARDL method and EViews 9 software were used in the estimation.
Results: With the increase of economic complexity variables, energy price-energy intensity interrelationship, internet users and foreign direct investment, the amount of carbon dioxide emissions decreases in both short-term and long-term periods. The variables of mutual effects of economic risk-investment and capital per capita on pollution did not have a significant effect in both time periods. Commercial liberalization and urbanization have created a significant negative impact on the quality of the environment in the short and long term.   
Discussion: The improvement of economic complexity has led to the dominance of technical and structural effect over scale effect and has reduced pollution. The increase in investment in the country, along with the reduction of economic risk, has not yet reached a level that can reduce pollution through the channel of economic growth. With the increase in energy prices, incentives have been placed in the direction of increasing energy efficiency, as a result of which pollution is reduced. As a result of the increase in exports due to trade liberalization, the use of resources and energy has been inappropriate, and in this regard, environmental laws and standards have also been ignored. The expansion of urbanization has increased the pollution with the expansion of economic activities, and in this regard, it has not been able to reduce the intensity of energy and pollution for public urban infrastructures through the creation of economies of scale. Foreign direct investment reduces pollution with the possibility of improving energy efficiency through technology spillover from foreign companies to domestic companies.