Emissions and atmospheric processes influence the chemical composition and toxicological properties of urban air particulate matter in Nanjing, China

Abstract

Ambient inhalable particulate matter (PM) is a serious health concern worldwide, but especially so in China where high PM concentrations affect huge populations. Atmospheric processes and emission sources cause spatial and temporal variations in PM concentration and chemical composition, but their influence on the toxicological characteristics of PM are still inadequately understood. In this study, we report an extensive chemical and toxicological characterization of size-segregated urban air inhalable PM collected in August and October 2013 from Nanjing, and assess the effects of atmospheric processes and likely emission sources. A549 human alveolar epithelial cells were exposed to day- and nighttime PM samples (25, 75, 150, 200, 300 μg/ml) followed by analyses of cytotoxicity, genotoxicity, cell cycle, and inflammatory response. PM and PM caused the greatest toxicological responses for different endpoints, illustrating that particles with differing size and chemical composition activate distinct toxicological pathways in A549 cells. PM displayed the greatest oxidative stress and genotoxic responses; both were higher for the August samples compared with October. In contrast, PM and PM samples displayed high cytotoxicity and substantially disrupted cell cycle; August samples were more cytotoxic whereas October samples displayed higher cell cycle disruption. Several components associated with combustion, traffic, and industrial emissions displayed strong correlations with these toxicological responses. The lower responses for PM compared to PM and PM indicate diminished toxicological effects likely due to aerosol aging and lower proportion of fresh emission particles rich in highly reactive chemical components in the PM fraction. Different emission sources and atmospheric processes caused variations in the chemical composition and toxicological responses between PM fractions, sampling campaigns, and day and night. The results indicate different toxicological pathways for coarse-mode particles compared to the smaller particle fractions with typically higher content of combustion-derived components. The variable responses inside PM fractions demonstrate that differences in chemical composition influence the induced toxicological responses.

Urban air particulate matter induces mitochondrial dysfunction in human olfactory mucosal cells

“…Initial metabolic activity and cytotoxicity assessment were carried out assessing PM concentrations ranging from 6.5 μg/ml to 100 μg/ml (see Figure S1). At 50 μg/ ml, reduced metabolic activity in cells can be observed without overt cytotoxicity, allowing for some recapitulation of cellular damage in chronic exposure to PM in vivo [3,19]. A 24-h incubation with the different PM size classes did not result in differences in LDH release into the culture medium ( Fig.…”

“…Urban size-segregated PM 1-0.2 , PM 2.5-1 and PM 10-2.5 were collected from Nanjing, China with a high volume cascade impactor and reconstituted as described [3]. Detailed information on the collection site, meteorology, chemistry and protocols in Table S2 in Supplementary Information and are described [3,19]. Despite high concentrations of PM in the sampling location, the mass of the ultrafine particles was relatively low.…”

Regional Inhaled Deposited Dose of Urban Aerosols in an Eastern Mediterranean City

“…An American Cancer Society study and a large number of follow-up studies have identified ambient particulate matter (PM) mass concentrations as a health-relevant metric [9,10]. The burden of disease from particulate air pollution is mainly associated with the fine (0.1 to 2.5 µm) and ultrafine (<0.1 µm) fractions [11][12][13][14][15][16]. A range of studies also show that not only particle mass is of importance for determining health outcomes, but also other aerosol metrics, including number concentrations, surface area concentrations, and chemical composition [17][18][19][20].…”

Urban air PM modifies differently immune defense responses against bacterial and viral infections in vitro

“… 1 ; 2 ; 3 ; 4 ; 5 ; 6 ; 7 ; 8 ; 9 ; 10 ; 11 ; 12 ; 13 ; 14 ; 15 ; 16 ; 17 ; 18 ; 19 ; 20 ; 21 ; 22 ; 23 ; 24 ; 25 ; 26 ; 27 ; 28 ; 29 ; 30 ; 31 ; 32 ; 33 ; 34 ; 35 ; 36 ; 37 ; 38 ; 39 ; 40 ; 41 ; 42 ; 43 ; 44 ; 45 ; 46 ; 47 ; 48 ; 49 ; 50 ; 51 ; 52 .…”