Nitrogen oxides and ozone in urban air: A review of 50 plus years of progress

Abstract

Nitrogen oxides and ozone impact air quality in many parts of the United States, Europe, China, and many other countries. The greatest air quality challenge in Los Angeles, some other areas of California, and some parts of China is to reduce ozone levels to meet regulations. Background ozone is a major factor which makes it more difficult to reduce urban concentrations in Los Angeles and some other locations. Air pollution from China affects the background ozone entering California. More than 50 years of history are reviewed with an emphasis on reducing concentrations of nitrogen oxides and ozone. During this time period, there has been significant progress in reducing levels of these pollutants in urban air in the United States and Europe; however, ozone concentrations in China have increased since 2013. Cost and benefit analysis has shown that benefits associated with the Clean Air Act of 1970 have greatly exceeded costs to improve air quality in the U.S. over the past 50 years. Further actions to consider to improve air quality include reducing combustion of coal and petroleum products and transitioning to renewable energy. Public education is recommended to inform citizens that the benefits of reducing emissions far exceed costs.

Impacts of Soil NOx Emission on O3 Air Quality in Rural California

“…However, the trend of tropospheric NO 2 column densities (columns) observed by satellites and nationwide NO 2 concentrations predicted by an ensemble of models are both inconsistent with the sustained decrease in NO x emissions reported by the NEI, which stopped decreasing after the year of 2009. , Silvern et al separated OMI observations into winter and summer as well as urban and rural and found that OMI NO 2 in rural summer during the 2005–2017 period had no significant reduction trend. Furthermore, an increase in daily nonpeak O 3 concentration was observed in many parts of the U.S. − Recent studies suggest that this enhancement of O 3 can be mainly attributed to the temperature-driven increase in NO x emission, mostly from soils. , Consequently, soils may be an important source of NO x that has been overlooked in previous studies and regulatory frameworks but has a potentially increased impact on tropospheric NO x budget and O 3 pollution.…”

Analysis on the Characteristics of Air Pollution in China during the COVID-19 Outbreak

“…It has been previously reported that 90% of sulfur dioxide (SO 2 ) and 67% of nitrogen oxides (NO x ) in China are emitted by coal combustion, and on-road mobile sources contribute to emissions of NO x [30][31][32][33]. The presence of NO x in the air is important for the formation of O 3 , and O 3 concentrations in China have increased since 2013 [34]. Changes in urbanization and economic levels have a non-negligible impact on air pollution [35].…”

Ethylenediurea (EDU) spray effects on willows (Salix sachalinensis F. Schmid) grown in ambient or ozone-enriched air: implications for renewable biomass production

“…Due to its complex chemistry, the control of O 3 levels is challenging, and O 3 can remain at elevated concentrations even if the emissions of some O 3 precursors are highly decreased (Sicard et al 2020;Querol et al 2021;Sicard 2021). Being also affected by transboundary long-range transport (Gao et al 2020;Erickson et al 2020), which downplays national efforts to decrease O 3 concentrations, O 3 levels may remain elevated for several decades to come (Sicard et al 2017). Such elevated O 3 levels can lead to inhibited photosynthesis and suppressed woody biomass production and yields (Paoletti 2006;Karnosky et al 2007a;Koike et al 2013;Jolivet et al 2016;Li et al 2017;Cotrozzi 2021), suggesting increased risks to tree productivity (Sicard et al 2017;Feng et al 2019a;Proietti et al 2021;Sacchelli et al 2021).…”