Changes in apparent temperature and PM<sub>2.5</sub> around the Beijing–Tianjin megalopolis under greenhouse gas and stratospheric aerosol intervention scenarios
<p>Apparent temperature (AP) and ground-level aerosol pollution (PM<span class="inline-formula"><sub>2.5</sub></span>) are important factors in human health, particularly in rapidly growing urban centers in the developing world. We quantify how changes in appa...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2023-09-01
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| Series: | Earth System Dynamics |
| Online Access: | https://esd.copernicus.org/articles/14/989/2023/esd-14-989-2023.pdf |
| Summary: | <p>Apparent temperature (AP) and ground-level aerosol
pollution (PM<span class="inline-formula"><sub>2.5</sub></span>) are important factors in human health, particularly
in rapidly growing urban centers in the developing world. We quantify how
changes in apparent temperature – that is, a combination of 2 m air
temperature, relative humidity, surface wind speed, and PM<span class="inline-formula"><sub>2.5</sub></span>
concentrations – that depend on the same meteorological factors along with
future industrial emission policy may impact people in the greater Beijing
region. Four Earth system model (ESM) simulations of the modest greenhouse
emissions RCP4.5 (Representative Concentration Pathway), the “business-as-usual” RCP8.5, and the stratospheric
aerosol intervention G4 geoengineering scenarios are downscaled using both a
10 km resolution dynamic model (Weather Research and Forecasting, WRF) and a statistical approach (Inter-Sectoral Impact Model Intercomparison
Project – ISIMIP).
We use multiple linear regression models to simulate changes in PM<span class="inline-formula"><sub>2.5</sub></span>
and the contributions meteorological factors make in controlling seasonal AP
and PM<span class="inline-formula"><sub>2.5</sub></span>. WRF produces warmer winters and cooler summers than
ISIMIP both now and in the future. These differences mean that estimates of
numbers of days with extreme apparent temperatures vary systematically with
downscaling method, as well as between climate models and scenarios. Air
temperature changes dominate differences in apparent temperatures between
future scenarios even more than they do at present because the reductions in
humidity expected under solar geoengineering are overwhelmed by rising vapor
pressure due to rising temperatures and the lower wind speeds expected in the
region in all future scenarios. Compared with the 2010s, the PM<span class="inline-formula"><sub>2.5</sub></span>
concentration is projected to decrease by 5.4 <span class="inline-formula">µ</span>g m<span class="inline-formula"><sup>−3</sup></span> in the
Beijing–Tianjin province under the G4 scenario during the 2060s from the WRF
downscaling but decrease by 7.6 <span class="inline-formula">µ</span>g m<span class="inline-formula"><sup>−3</sup></span> using ISIMIP. The relative
risk of five diseases decreases by 1.1 %–6.7 % in G4, RCP4.5, and RCP8.5 using
ISIMIP but has a smaller decrease (0.7 %–5.2 %) using WRF. Temperature
and humidity differences between scenarios change the relative risk of
disease from PM<span class="inline-formula"><sub>2.5</sub></span> such that G4 results in 1 %–3 % higher health risks
than RCP4.5. Urban centers see larger rises in extreme apparent temperatures
than rural surroundings due to differences in land surface type, and since
these are also the most densely populated, health impacts will be dominated
by the larger rises in apparent temperatures in these urban areas.</p> |
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| ISSN: | 2190-4979 2190-4987 |