Global-Scale Patterns and Trends in Tropospheric NO2 Concentrations, 2005–2018

Abstract

Nitrogen dioxide (NO2) is an important air pollutant with both environmental and epidemiological effects. The main aim of this study is to analyze spatial patterns and temporal trends in tropospheric NO2 concentrations globally using data from the satellite-based Ozone Monitoring Instrument (OMI). Additional aims are to compare the satellite data with ground-based observations, and to find the timing and magnitude of greatest breakpoints in tropospheric NO2 concentrations for the time period 2005–2018. The OMI NO2 concentrations showed strong relationships with the ground-based observations, and inter-annual patterns were especially well reproduced. Eastern USA, Western Europe, India, China and Japan were identified as hotspot areas with high concentrations of NO2. The global average trend indicated slightly increasing NO2 concentrations (0.004 × 1015 molecules cm−2 y−1) in 2005–2018. The contribution of different regions to this global trend showed substantial regional differences. Negative trends were observed for most of Eastern USA, Western Europe, Japan and for parts of China, whereas strong, positive trends were seen in India, parts of China and in the Middle East. The years 2005 and 2007 had the highest occurrence of negative breakpoints, but the trends thereafter in general reversed, and the highest tropospheric NO2 concentrations were observed for the years 2017–2018. This indicates that the anthropogenic contribution to air pollution is still a major issue and that further actions are necessary to reduce this contribution, having a substantial impact on human and environmental health.

Calibration and assessment of electrochemical low-cost sensors in remote alpine harsh environments

“…This work was based on the data of the regional environmental agency: a survey on ozone and nitrogen dioxide at Passo Valles Therefore, even if it was not possible to know the NO 2 concentration at MRG, the mean values measured at Passo Valles suggest that a few ppb of NO 2 may have interfered with our experiment in MRG. Nevertheless, since it has been observed that the NO 2 concentrations are decreasing all over Europe (Jamali et al, 2020;Castellanos and Boersma, 2012), it is unlikely that NO 2 interference could have been detected by our LCSs system in MRG and thus explain some of the bias we observed between the LCSs and the reference instrument.…”

Comparing the long‐term effects of artificial and natural vegetation restoration strategies: A case‐study of Wuqi and its adjacent counties in northern China

“…The spatial distribution of artificial and natural vegetation restoration strategies was identified using the DBEST method. Jamali et al (2015) proposed the DBEST program for analyzing vegetation time series, which has been applied to the time series breakpoint detection of vegetation or other factors in different regions (Jamali et al, 2020; Shen et al, 2018; York et al, 2020). Combining the DBEST method with the identification of vegetation restoration strategies is an expansion of the application fields of the DBEST method that also provides methodological support for the visualization of ecological policy data.…”

Long-Term Variation in the Tropospheric Nitrogen Dioxide Vertical Column Density over Korea and Japan from the MAX-DOAS Network, 2007–2017

“…NOx emissions in China significantly increased due to rapid industrialization, economic growth, and urbanization during the two decades before the 2010s [6][7][8], but started to decrease in the early 2010s [9,10] due to the effectiveness of China's Clean Air Action [11,12]. In particular, NOx emissions in eastern China from the Multi-resolution Emission Inventory for China (MEIC) decreased by 21% in 2017 relative to 2013, which is a smaller decrease than the 30% decrease observed by the Ozone Monitoring Instrument (OMI) in NO 2 columns over the same region during the same period [11].…”