Contribution of anthropogenic pollutant sources to greenhouse gas emissions: a case study from a developing country

Anthropogenic greenhouse gas (GHG) emissions are the primary cause of climate change, one of the biggest challenges for humankind. To tackle this problem, the international community is looking for ways to reduce GHG emissions. To create reduction strategies in a city/province/country, there is a need for an inventory that provides emission amounts from different sectors. This study aimed to develop a GHG emission inventory for Karaj, a megacity in Iran, using international guidelines such as AP-42 and ICAO, and IVE software. The emissions of mobile sources were accurately calculated by a bottom-up method. The results showed that power plant with 47% of the total emissions is the primary GHG contributor in Karaj. Residential and commercial units with 27% and mobile sources with 24% of the total emissions play a critical role in emitting GHGs in Karaj. On the other hand, the industrial units and the airport have negligible (2%) contribution to the total emissions. Subsequent estimates showed that GHG emissions per capita and per GDP of Karaj were 6.03 t per person and 0.47 t per thousand US dollars, respectively. These amounts are higher than the global averages (4.97 t per person and 0.3 t per thousand US dollars). The relatively high GHG emissions in Karaj are due to the sole reliance on the consumption of fossil fuels. To reduce emissions, mitigation strategies such as developing renewable energy sources, switching to low-emission transportation, and raising public awareness should be implemented.