English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

. The absence of up-to-date emissions has been a major impediment toaccurately simulating aspects of atmospheric chemistry and to preciselyquantifying the impact of changes in emissions on air pollution. Hence, anonlinear joint analytical inversion (Gauss–Newton method) of both volatileorganic compounds (VOCs) and nitrogen oxide (NOx) emissions is made byexploiting the Smithsonian Astrophysical Observatory (SAO) Ozone Mapping andProfiler Suite Nadir Mapper (OMPS-NM) formaldehyde (HCHO) and the NationalAeronautics and Space Administration (NASA) Ozone Monitoring Instrument(OMI) tropospheric nitrogen dioxide (NO2) columns during theKorea–United States Air Quality (KORUS-AQ) campaign over East Asia inMay–June 2016. Effects of the chemical feedback of NOx and VOCs on bothNO2 and HCHO are implicitly included by iteratively optimizing theinversion. Emission uncertainties are greatly narrowed (averagingkernels &gt; 0.8, which is the mathematical presentation of thepartition of information gained from the satellite observations with respectto the prior knowledge) over medium- to high-emitting areas such as citiesand dense vegetation. The prior amount of total NOx emissions is mainlydictated by values reported in the MIX-Asia 2010 inventory. After theinversion we conclude that there is a decline in emissions (before, after, change) forChina (87.94±44.09 Gg d−1, 68.00±15.94 Gg d−1, −23 %), NorthChina Plain (NCP) (27.96±13.49 Gg d−1, 19.05±2.50 Gg d−1,−32 %), Pearl River Delta (PRD) (4.23±1.78 Gg d−1, 2.70±0.32 Gg d−1, −36 %), Yangtze River Delta (YRD) (9.84±4.68 Gg d−1,5.77±0.51 Gg d−1, −41 %), Taiwan (1.26±0.57 Gg d−1,0.97±0.33 Gg d−1, −23 %), and Malaysia (2.89±2.77 Gg d−1,2.25±1.34 Gg d−1, −22 %), all of which have effectively implementedvarious stringent regulations. In contrast, South Korea (2.71±1.34 Gg d−1, 2.95±0.58 Gg d−1, +9 %) and Japan (3.53±1.71 Gg d−1, 3.96±1.04 Gg d−1, +12 %) are experiencing an increase inNOx emissions, potentially due to an increased number of diesel vehicles andnew thermal power plants. We revisit the well-documented positive bias (by afactor of 2 to 3) of MEGAN v2.1 (Model of Emissions of Gases and Aerosolsfrom Nature) in terms of biogenic VOC emissions inthe tropics. The inversion, however, suggests a larger growth of VOCs (mainlyanthropogenic) over NCP (25 %) than previously reported (6 %) relativeto 2010. The spatial variation in both the magnitude and sign of NOx andVOC emissions results in nonlinear responses of ozone production and loss. Dueto a simultaneous decrease and increase in NOx∕VOC over NCP and YRD, weobserve a ∼53 % reduction in the ratio of the chemical lossof NOx (LNOx) to the chemical loss of ROx(RO2+HO2) over the surface transitioning toward NOx-sensitive regimes, whichin turn reduces and increases the afternoon chemical loss and production of ozonethrough NO2+OH (−0.42 ppbv h−1)∕HO2 (and RO2)+NO(+0.31 ppbv h−1). Conversely, a combined decrease in NOx andVOC emissions in Taiwan, Malaysia, and southern China suppresses theformation of ozone. Simulations using the updated emissions indicateincreases in maximum daily 8 h average (MDA8) surface ozone over China(0.62 ppbv), NCP (4.56 ppbv), and YRD (5.25 ppbv), suggesting that emissioncontrol strategies on VOCs should be prioritized to curb ozone productionrates in these regions. Taiwan, Malaysia, and PRD stand out as regionsundergoing lower MDA8 ozone levels resulting from the NOx reductionsoccurring predominantly in NOx-sensitive regimes.

atmospheric chemistry and physics

An inversion of NO&amp;lt;sub&amp;gt;&amp;lt;i&amp;gt;x&amp;lt;/i&amp;gt;&amp;lt;/sub&amp;gt; and non-methane volatile organic compound (NMVOC) emissions using satellite observations during the KORUS-AQ campaign and implications for surface ozone over East Asia