# Long-Term and Seasonal Changes in Sources of Urban Atmospheric Particulates in the Western Pacific
## 3 Results and Discussion
### Individual City Trends
Table 3 shows that the [P\({}_{\rm h}\)]/[P\({}_{\rm c}\)] ratio in Kitakyushu (0.34) was much smaller than the [P\({}_{\rm h}\)]/[P\({}_{\rm c}\)] ratios in other Japanese cities (0.70-0.85). Considering that Kitakyushu is a typical steel manufacturing city (Table S1), these results suggest that coke oven plants, which consume large amounts of coal, were the main contributor to P\({}_{\rm c}\). We collected TSP samples in Muorran, another steel manufacturing city in Japan, in our previous study [24]. The [P\({}_{\rm h}\)]/[P\({}_{\rm c}\)] ratio of Muorran was much smaller (0.11), as calculated by the NP-method. These results suggest that coke oven plants were the main contributor to P\({}_{\rm l}\). It should be emphasized that the annual [P\({}_{\rm c}\)] in Kitakyushu was as low as the annual [P\({}_{\rm c}\)] in the other Japanese cities. This result suggests that P\({}_{\rm c}\) was effectively removed from coke oven emissions through PM/sulfur oxides precipitators and filters [25]. $\text{$2 Sources of Atmospheric Total Suspended Particulate (TSP) and Combustion-Derived Particulates (P\({}_{\rm c}\)) in Kanazawa. P\({}_{\rm c}\) combustion-derived particulate matter; P\({}_{\rm n}\) non-combustion-derived particulate matter; P\({}_{\rm h}\) particulates from combustion sources with high-temperature; P\({}_{\rm l}\) particulates from combustion sources with low-temperature. Among the three Chinese cities, Shenyang and Beijing showed much higher winter [P\({}_{\rm c}\)] (more than 40 \(\mu\)g m\({}^{-3}\)) than Shanghai (3.37 \(\mu\)g m\({}^{-3}\)) (Table 2). This was reflected in higher [TSP] values (Table S1) and much larger \(y\) (=[P\({}_{\rm c}\)]/[TSP]) values in these two cities in winter than in summer (Table S3). Figure 3 shows the profiles of [TSP] and [P\({}_{\rm c}\)] in Beijing, where large seasonal changes (summer \(<\) winter) were observed in [P\({}_{\rm c}\)], as well as in the [P\({}_{\rm c}\)]/[TSP] ratio. The high winter [P\({}_{\rm c}\)] was mainly attributed to high [P\({}_{\rm l}\)]. In contrast to the large [P\({}_{\rm l}\)]/[P\({}_{\rm c}\)] ratio, the [P\({}_{\rm h}\)]/[P\({}_{\rm c}\)] ratio in Beijing (0.10) was much smaller than that in Shanghai (0.68) (Table 3). The [TSP] and [P\({}_{\rm c}\)] profiles in Shenyang and Vladivostok were similar to those in Beijing. Figure 4 shows the [TSP] and [P\({}_{\rm c}\)] profiles in Shanghai, where the [P\({}_{\rm c}\)] level was as low as those in Japanese cities, and its seasonal changes were not as large as those in Beijing. $\text{$3 Sources of Atmospheric Total Suspended Particulate (TSP) and Combustion-Derived Particulates (P\({}_{\rm c}\)) in Beijing. P\({}_{\rm c}\), P\({}_{\rm n}\), P\({}_{\rm h}\), and P\({}_{\rm l}\); The same as in Figure 1 caption. $\text{$4 Sources of Atmospheric Total Suspended Particulate (TSP) and Combustion-Derived Particulates (P\({}_{\rm c}\)) in Kitakyushu. P\({}_{\rm c}\), P\({}_{\rm n}\), P\({}_{\rm h}\), and P\({}_{\rm l}\); The same as in Figure 1 caption. However, the [P\({}_{\rm H}\)]/[P\({}_{\rm c}\)] ratio was much larger in Shanghai than in Beijing. Moreover, the winter to summer ratio of [P\({}_{\rm c}\)] of Shanghai (2.7) was much smaller than that of Beijing (33.0) (Table 2). Considering that coal is consumed for winter heating in northern and central China and far eastern Russia, these results suggest that the high winter [P\({}_{\rm I}\)] values in Shenyang, Beijing, and Vladivostok were ascribed to coal combustion for heating. In Shanghai, where winter heating is not used, the main contributor to P\({}_{\rm c}\) was vehicles. Thus, the Chinese cities differed significantly in the concentrations and sources of P\({}_{\rm c}\). [P\({}_{\rm c}\)] concentrations in Busan were as low as those in Japanese cities, and changed little with season (Table 2), although the monitoring period was not long.