Abstract
Abstract. Understanding how historical climate and land cover changes have affected tropospheric ozone in East Asia would help constrain the large uncertainties associated with future East Asian air quality projections. We perform a series of simulations using a global chemical transport model driven by assimilated meteorological data and a suite of land cover and land use data to examine the public health effects associated with changes in climate, land cover, land use, and anthropogenic emissions between the 5-year periods 1981–1985 and 2007–2011 in East Asia. We find that between these two periods land cover change alone could lead to a decrease in summertime surface ozone by up to 4 ppbv in East Asia and ~ 2000 fewer ozone-related premature deaths per year, driven mostly by enhanced dry deposition resulting from climate- and CO2-induced increase in vegetation density, which more than offsets the effect of reduced isoprene emission arising from cropland expansion. Climate change alone could lead to an increase in summertime ozone by 2–10 ppbv in most regions of East Asia and ~ 6000 more premature deaths annually, mostly attributable to warming. The combined impacts (−2 to +12 ppbv) show that while the effect of climate change is more pronounced, land cover change could offset part of the climate effect and lead to a previously unknown public health benefit. While the changes in anthropogenic emissions remain the largest contributor to deteriorating ozone air quality in East Asia over the past 30 years, we show that climate change and land cover changes could lead to a substantial modification of ozone levels, and thus should come into consideration when formulating future air quality management strategies. We also show that the sensitivity of surface ozone to land cover change is more dependent on dry deposition than on isoprene emission in most of East Asia, leading to ozone responses that are quite distinct from that in North America, where most ozone-vegetation sensitivity studies to date have been conducted.
Highlights
Air pollution is one of the most pressing environmental and public health concerns that we have to face today especially in rapidly developing regions such as East Asia
Our results indicate that the land use change such as cropland expansion in some regions could be beneficial for ozone air quality through reducing biogenic emissions, since crops are generally low-emitting species
We investigate the effects of changes in climate, land cover and land use between the periods 1981–1985 and 2007–2011 on surface ozone concentration in East Asia using the Goddard Earth Observing System (GEOS)-Chem chemical transport model driven by assimilated meteorological fields, land use data from historical RCP harmonization, and several satellite-derived land cover products
Summary
In this study, using historical meteorological and satellitederived land cover data to drive a chemical transport model, we examine the individual and combined effects of changes in climate, land cover and land use on tropospheric ozone in East Asia between the 5-year periods 1981–1985 and 2007– 2011, accounting for a more comprehensive set of potentially interacting mechanisms and variables including LAI (representing vegetation density), biogenic and soil NOx emissions, and dry deposition, in addition to PFT (representing vegetation distribution) We compare such effects with the contribution from anthropogenic emission changes over the same period. We further calculate the annual mortality attributable to respiratory diseases caused by ozone pollution by applying concentration-response functions from epidemiological cohort studies, as a means to explore the public health implications of historical climate change and land use trends in East Asia
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
