A study to characterize the lead isotopic fingerprint in PM2.5 emitted from incense stick and cigarette burning.

The incense sticks and cigarettes burning are key sources of particulate matter with a diameter of ≤ 2.5 µm (PM2.5) in indoor and outdoor air. While lead (Pb) isotope ratios provide valuable insights into the origin of particle pollution, their applicability for investigating these source remains unclear. The Pb isotope ratios in the PM2.5 emitted from these two sources were analyzed, and effects of brands or nicotine contents on the ratios were assessed. In addition, As, Cr, and Pb were analyzed to investigate whether Pb isotope ratios can serve as an indicator for the source investigation of these metals. We found that average ratios of 206Pb/204Pb, 206Pb/207Pb, and 208Pb/207Pb in cigarettes were heavier than those in incense sticks. Scatter plots of Pb isotope ratios indicated an overlap of values for incense sticks or cigarettes linked to different brands, in that ratios for cigarettes with high nicotine content were heavier than for those with low nicotine content. Scatter plots of As, Cr, or Pb concentration against Pb isotope ratios clearly distinguished the effects of cigarette burning versus incense sticks with respect to PM2.5 of these metals. Results indicate that brand differences did not affect the determination of PM2.5 in these two sources. We suggest that Pb isotope ratios can be a useful tool in investigating the influence of incense sticks and of cigarettes (with high or low nicotine content) burning to PM2.5 and associated metals.

Isotopic signatures and source apportionment of Pb in ambient PM2.5.

Particulate lead (Pb) is a primary air pollutant that affects society because of its health impacts. This study investigates the source sectors of Pb associated with ambient fine particulate matter (PM2.5) over central-western Taiwan (CWT) with new constraints on the Pb-isotopic composition. We demonstrate that the contribution of coal-fired facilities is overwhelming, which is estimated to reach 35 ± 16% in the summertime and is enhanced to 57 ± 24% during the winter monsoon seasons. Moreover, fossil-fuel vehicles remain a major source of atmospheric Pb, which accounts for 12 ± 5%, despite the current absence of a leaded gasoline supply. Significant seasonal and geographical variations in the Pb-isotopic composition are revealed, which suggest that the impact of East Asian (EA) pollution outflows is important in north CWT and drastically declines toward the south. We estimate the average contribution of EA outflows as accounting for 35 ± 15% (3.6 ± 1.5 ng/m3) of the atmospheric Pb loading in CWT during the winter monsoon seasons.

Wintertime haze deterioration in Beijing by industrial pollution deduced from trace metal fingerprints and enhanced health risk by heavy metals.

Airborne particulate matter (PM) was collected in Beijing between 24 February and 12 March 2014 to investigate chemical characteristics and potential industrial sources of aerosols along with health risk of haze events. Results showed secondary inorganic aerosol was the major contributor to PM2.5 during haze days. Utilizing specific elements, including Fe, La, Tl and As, as fingerprinting tracers, four emission sources, namely iron and steel manufacturing, petroleum refining, cement plant, and coal combustion were explicitly identified; their elevated contributions to PM during haze days were also estimated. The average cancer risk from exposure to inhalable PM toxic metals was 1.53 × 10(-4) on haze days, which is one order of magnitude higher than in other developed cities. These findings suggested heavy industries emit large amounts of not only primary PM but also precursor gas pollutants, leading to secondary aerosol formation and harm to human health during haze days.

Tungsten and other heavy metal contamination in aquatic environments receiving wastewater from semiconductor manufacturing.

Through analyses of water and sediments, we investigate tungsten and 14 other heavy metals in a stream receiving treated effluents from a semiconductor manufacturer-clustered science park in Taiwan. Treated effluents account for ∼ 50% of total annual river discharge and <1% of total sediment discharge. Dissolved tungsten concentrations in the effluents abnormally reach 400 µg/L, as compared to the world river average concentration of <0.1 µg/L. Particulate tungsten concentrations are up to 300 µg/g in suspended and deposited sediments, and the corresponding enrichment factors are three orders of magnitude higher than average crust composition. Surprisingly, the estimated amount of tungsten exported to the adjacent ocean is 23.5 t/yr, which can approximate the amount from the Yangtze River should it be unpolluted. This study highlights the urgency of investigating the biological effect of such contamination.

Evaluating real-time air-quality data as earthquake indicator.

A catastrophic earthquake, namely the 921-earthquake, occurred with a magnitude of M(L)=7.3 in Taiwan on September 21, 1999, causing severe disaster. The evaluation of real-time air-quality data, obtained by the Taiwan Environmental Protection Administration (EPA), revealed a staggering increase in ambient SO(2) concentrations by more than one order of magnitude across the island several hours prior to the earthquake, particularly at background stations. The abrupt increase in SO(2) concentrations likely resulted from seismic-triggered degassing instead of air pollution. An additional case of a large earthquake (M(L)=6.8), occurring on March 31, 2002, was examined to confirm our observations of significantly enhanced SO(2) concentrations in ambient air prior to large earthquakes. The coincidence between large earthquakes and increases in trace gases during the pre-quake period (several hours) indicates the potential of employing air-quality monitoring data to forecast catastrophic earthquakes.

Variations of Cd/Pb and Zn/Pb ratios in Taipei aerosols reflecting long-range transport or local pollution emissions.

Along with windblown dust, large quantities of pollutants are annually brought out of continental China by the westerlies in winter and spring; thereafter, they are partly subjected to transport by northeastern monsoon winds to Taiwan. To characterize the heavy metal composition differences between long-range transported and local aerosols and to evaluate metal contributions from long-range transported aerosols during the northeastern monsoon season, both PM(10) and PM(2.5) aerosols collected from Taipei, Taiwan from February 2002 to March 2003 were analyzed for three selected heavy metals, namely Pb, Cd and Zn using ICP-MS. Monthly patterns show that Pb concentrations in winter (62 ng/m(3)) were over two times higher than those in the other seasons, which is attributed to long-range transport from areas under development in China. Low Cd/Pb (0.017) and Zn/Pb (1.82) ratios were measured in aerosols collected during the Asian dust period, in which the ambient aerosols consisted predominantly of long-range transported pollutants. By contrast, high Cd/Pb (0.030) and Zn/Pb (3.44) ratios were observed during the summer monsoon season, in which aerosols were dominated by local pollutant emissions. Cd/Pb and Zn/Pb ratios appear to be successfully applied to identify the pollutants originating principally from the long-range transport or from local emissions. In addition, by assuming that a significant fraction of heavy metals associated with coarse airborne dust have settled to the sea prior to reaching Taiwan in spring, a mechanism is suggested to explain why higher anthropogenic metal concentrations occurred in winter than those in dust-rich spring.