Environmental Impact Assessment

01 Make a plan

This guidance speaks to the value of the environment, natural habitats and biodiversity that also suffer from air pollution. Who speaks for the animals? What value is there for society in natural, wild spaces? These are questions that air quality management needs to address to help broaden the economic value of clean air programs. Start by getting a good overview of the process and data needs by learning about several aspects of valuing nature and the environment in the resources below.

02 Estimate impact on ecosystem services

Clean air and clean water occur naturally. Unfortunately, man-made emissions into the environment degrade nature’s ability to keep the air and water clean. A terrestrial ecosystem is conventionally viewed as an assemblage of living organisms interacting in a complex way with one another and with their environment, air, soil, and water. The process by which the natural biosphere, atmosphere, soil and the water cycle purify itself have a value that is degraded by air pollution. The tools below can help to assess the impact on the ecosystem services provided by natural systems.

03 Understand the relevance of sustainable nitrogen management

Nitrogen is naturally present in the atmosphere, soils and food crops. However, over the past 100 years, humans have converted nitrogen into many reactive nitrogen (Nr) forms, through fertilizer and munitions manufacturing and burning of fossil fuels. This has caused unprecedented changes to the global nitrogen cycle, leading to a doubling of the flow of nitrogen compounds around the world in the past 100 years. Nitrogen is important for plant growth and sufficient amounts are needed for plants to achieve optimum crop yields. However, about 80 per cent of nitrogen dispersed as fertilizer is lost from agriculture through leaching and run-off of nitrate or organic nitrogen and gaseous emissions to air (leading to secondary formation of PM2.5).

The nitrogen that is lost to the environment has severe impacts on soils, air, freshwaters and has implications for climate and stratospheric ozone depletion. Changes to the chemical composition of surface waters from deposition of nitrogen, metals and many other chemicals have left many water bodies unable to provide the ecosystem services discussed in the previous step. Learn more about nitrogen impacts in the resources below.

04 Understand the relevance of natural capital impacts

A standard framework for natural capital accounting developed by the United Nations and partner organizations describes several categories of natural capital accounts. One of these, ecosystem accounts, tracks the extent and condition of ecosystem assets and the flows of ecosystem services they provide to people and the economy. Learn more about natural capital accounting in the resources below.

05 Understand the relevance of vegetation and soil carbon impacts

Reducing air pollution can lead to significant benefits for crops and soil carbon levels. Lower levels of pollutants such as ozone and particulate matter can improve crop yields by enhancing photosynthesis and reducing stress on plants. This can result in higher agricultural productivity and improved food security. Furthermore, decreased air pollution can also lead to a reduction in atmospheric deposition of pollutants on soil, which can help maintain soil health and fertility. Improved soil quality can enhance carbon sequestration, as healthier soils can store more carbon, leading to a positive impact on climate change mitigation. Overall, reducing air pollution not only benefits crop productivity and soil health but also plays a crucial role in promoting sustainability, resilience, and environmental well-being in agricultural systems.

06 Understand the relevance of visibility benefits

Reducing air pollution has significant benefits for visibility, as fine particles degrade visual range. Enhanced visibility can positively impact tourism and bring economic benefits because clearer and more scenic views not only attract more visitors to destinations known for their natural beauty – boosting tourism and spending on recreational services – but also contribute to increased spending on accommodations, dining, and other local services. Additionally, clearer skies and better visibility conditions enhance flight safety, air traffic control operations, reduce delays, and increase capacity at airports.

07 Understand the relevance of forest benefits

Mitigating air pollution stress factors can support the long-term sustainability and vitality of forest ecosystems. Lower pollution levels can improve overall forest health by reducing damage to tree foliage, bark, and sensitive plant tissues caused by pollutants like ozone and nitrogen compounds.

This can enhance forest resilience to environmental stressors, pests, and diseases, leading to stronger and more diverse forest ecosystems. Improved air quality can also promote the growth and regeneration of forest vegetation, including trees, shrubs, and understory plants. Healthy forests play a crucial role in mitigating climate change by sequestering carbon dioxide and helping maintain biodiversity. Furthermore, decreased air pollution can reduce acid rain and soil acidification, preserving soil quality and nutrient cycling within forest ecosystems.

08 Understand the relevance of time savings and productivity enhancement

Air pollution mitigation strategies can lead to significant time savings across various sectors. By reducing traffic congestion through measures like promoting public transportation, carpooling, and implementing emission controls, commute times can be shortened, resulting in less time spent on roads and highways. Improved air quality can also enhance visibility, reducing delays and disruptions in air, land, and sea transportation.

Moreover, mitigating air pollution can lead to fewer health issues and sick days for both indoor and outdoor workers, boosting productivity in workplaces, schools and for outdoor workers. Reduced air pollution-related illnesses can result in lower healthcare costs and decreased time spent on medical visits and treatments. Cleaner cooking technologies, such as improved cookstoves and alternative fuels, can save significant time for women and girls who would otherwise spend hours collecting firewood, a task that can be physically demanding, time-consuming, and often hazardous.

09 Understand the relevance of climate benefits

Simultaneous mitigation of air pollution and climate change is facilitated by the fact that many emissions originate from common sources, such as industrial processes, transportation, and energy production. Many air pollutants, such as black carbon, methane, and tropospheric ozone, are also potent short-lived climate pollutants (SLCPs) that have warming effects on the atmosphere. 

By targeting these shared emission sources with integrated policies and strategies, jurisdictions can achieve dual benefits, effectively reducing both local air pollutants, GHG emissions and SLCPs in a more streamlined and coordinated manner. This synergistic approach not only enhances the efficiency of mitigation efforts but also may provide access to carbon finance for measures that have clean air benefits, highlighting the importance of addressing air quality and climate change in a holistic and integrated way.

10 Develop a valuation approach

If you choose to select specific environmental or other sustainable development benefits to value (i.e., ecosystem service, vegetation, biodiversity, carbon sequestration, visibility, traffic congestion mitigation, etc.), develop an approach for including this value within your air quality decision support and assessment framework (see Decision support guidance). This may range from specific quantitative estimates of impacts avoided or benefits yielded, monetized estimates of the value of those impacts based upon a valuation methodology or simply acknowledging the value qualitatively.