Tropospheric Ozone Assessment Report: Present-day ozone distribution and trends relevant to human health
Journal article, 2018
This study quantifies the present-day global and regional distributions (2010-2014) and trends (2000-2014) for five ozone metrics relevant for short-term and long-term human exposure. These metrics, calculated by the Tropospheric Ozone Assessment Report, are: 4th highest daily maximum 8-hour ozone (4MDA8); number of days with MDA8 > 70 ppb (NDGT70), SOMO35 (annual Sum of Ozone Means Over 35 ppb) and two seasonally averaged metrics (3MMDA1; AVGMDA8). These metrics were explored at ozone monitoring sites worldwide, which were classified as urban or non-urban based on population and nighttime lights data. Present-day distributions of 4MDA8 and NDGT70, determined predominantly by peak values, are similar with highest levels in western North America, southern Europe and East Asia. For the other three metrics, distributions are similar with North-South gradients more prominent across Europe and Japan. Between 2000 and 2014, significant negative trends in 4MDA8 and NDGT70 occur at most US and some European sites. In contrast, significant positive trends are found at many sites in South Korea and Hong Kong, with mixed trends across Japan. The other three metrics have similar, negative trends for many non-urban North American and some European and Japanese sites, and positive trends across much of East Asia. Globally, metrics at many sites exhibit non-significant trends. At 59% of all sites there is a common direction and significance in the trend across all five metrics, whilst 4MDA8 and NDGT70 have a common trend at similar to 80% of all sites. Sensitivity analysis shows AVGMDA8 trends differ with averaging period (warm season or annual). Trends are unchanged at many sites when a 1995-2014 period is used; although fewer sites exhibit non-significant trends. Over the longer period 1970-2014, most Japanese sites exhibit positive 4MDA8/SOMO35 trends. Insufficient data exist to characterize ozone trends for the rest of Asia and other world regions.
metrics
trends
ozone
global
human health
present day
Author
Zoe L. Fleming
University Of Leicester
Ruth M. Doherty
University of Edinburgh
Erika von Schneidemesser
Institute for Advanced Sustainability Studies (IASS)
Christopher S. Malley
Natural Environment Research Council (NERC)
University of York
University of Edinburgh
Owen R. Cooper
National Oceanic and Atmospheric Administration
University of Colorado at Boulder
Joseph P. Pinto
The University of North Carolina System
Augustin Colette
Institut National de l'Environnement Industriel et des Risques (INERIS)
Xiaobin Xu
Chinese Academy of Meteorological Sciences (CAMS)
Norwegian Meteorological Institute
Martin G. Schultz
Forschungszentrum
Jülich Research Centre
Allen S. Lefohn
ASL & Associates
Samera Hamad
University of Maryland
Raeesa Moolla
University of Witwatersrand
Sverre Solberg
Norwegian Institute for Air Research (NILU)
Zhaozhong Feng
Chinese Academy of Sciences
David Simpson
Chalmers, Space, Earth and Environment, Microwave and Optical Remote Sensing
Elementa
2325-1026 (eISSN)
Vol. 6 12ModElling the Regional and Global Earth system (MERGE)
Lund University (9945095), 2010-01-01 -- .
Subject Categories (SSIF 2011)
Physical Geography
Environmental Sciences
Climate Research
DOI
10.1525/elementa.302