Changing PM2.5 and related meteorology over India from 1950–2014: a new perspective from a chemistry-climate model ensemble

The model does not include explicit ammonium or nitrate aerosol chemistry, which can be important contributors to PM2.5, particularly in ammonia-rich regions.

“However, the model does not include explicit ammonium or nitrate aerosol chemistry, which can be important contributors to PM2 : 5, particularly in ammonia-rich regions (Nolte et al., 2018; Hancock et al., 2023).”

Previous evaluations have shown that WACCM reproduces the large-scale distributions of tropospheric ozone and key pollutants, as well as climatological patterns of aerosols, with skill comparable to other climate models.

“Previous evaluations have also shown that WACCM reproduces the large-scale distributions of tropospheric ozone and key pollutants, as well as climatological patterns of aerosols, with skill comparable to other climate models (Griffiths et al., 2021; Hancock et al., 2023).”

CESM2(WACCM6) is known to overestimate overall dust concentrations, which may contribute to dust appearing as the dominant PM2.5 species in many regions.

“Considering, however, that CESM2(WACCM6) is known to overestimate overall dust concentrations (e.g., Hancock et al., 2023), it is possible that this may contribute to dust appearing as the dominant PM2 : 5 species in many regions”

Hancock et al. (2023) indicated that estimates of PM2.5 may overestimate the contribution of dust due to the inclusion of larger dust particles.

“Furthermore, Hancock et al. (2023) has indicated that estimates of PM2 : 5 may overestimate the contribution of dust due to the inclusion of larger dust particles.”