Refined Sea Salt Markers for Coastal Cities Facilitating Quantification of Aerosol Aging and PM 2.5 Apportionment
Sea salt (ss) aerosols in PM are often quantified through source apportionment by applying sodium (Na ) and chloride (Cl ) as the markers, but both markers can be substantially emitted from anthropogenic sources. In this study, we differentiate ss from nonss (nss) portions of Na and Cl to better app...
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| Vydáno v: | Environmental science & technology Ročník 58; číslo 19; s. 8432 |
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| Hlavní autoři: | , , , , |
| Médium: | Journal Article |
| Jazyk: | angličtina |
| Vydáno: |
United States
14.05.2024
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| Témata: | |
| ISSN: | 1520-5851 |
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| Shrnutí: | Sea salt (ss) aerosols in PM
are often quantified through source apportionment by applying sodium (Na
) and chloride (Cl
) as the markers, but both markers can be substantially emitted from anthropogenic sources. In this study, we differentiate ss from nonss (nss) portions of Na
and Cl
to better apportion PM
in a coastal tropical urban environment. Size-resolved ionic profiles accounting for Cl
depletion of aged ss were applied to 162-day measurements during 2012 and 2018-2019. Results show that the nss (likely anthropogenic) portions, on average, account for 50-80% of total Na
and Cl
in submicron aerosols (PM
). This corresponds to up to 2.5 μg/m
of ss in submicron aerosols that can be ∼10 times overestimated if one attributes all Na
and Cl
in PM
to ss. Employing the newly speciated ss- and nss-portions of Na
and Cl
to source apportionment of urban PM
via positive matrix factorization uncovers a new source of transported anthropogenic emissions during the southwest monsoon, contributing to 12-15% of PM
. This increases anthropogenic PM
by ≥19% and reduces ss-related PM
by >30%. In addition to demonstrating Cl
depletion (aging) in submicron aerosols and quantifying ssNa
, nssNa
, ssCl
, as well as nssCl
therein, the refined PM
apportionment resolves new insights on PM
of anthropogenic origins in urban environments, useful to facilitate policy making. |
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| ISSN: | 1520-5851 |
| DOI: | 10.1021/acs.est.3c10142 |