Monitoring of ambient air PCDD/F levels in Portugal

Abstract

As part of a monitoring program conducted by IDAD -Institute for Environment and Development and supported by regional municipal solid waste (MSW) management authorities, dioxin concentrations in ambient air were measured in three regions of Portugal: Porto, Lisbon and Madeira. These independent studies were performed with the intention of providing data as a basis for the evaluation of potential impacts of the operation of recently built MSW incinerators. Thus, 170 samples were collected in nine different sites from January 1999 till present. The measured levels revealed an extremely variable content of PCDDs/PCDFs depending both on the area and the season of the year. Samples taken in Porto and Lisbon reveal a similar homologue structure even if concentrations measured in the Porto region are significantly greater. Data from Madeira is characteristic of a remote site with some of the congeners concentrations below the detection limit.

Spatial and Temporal Variation of PM2.5 and Atmospheric PCDD/Fs in Northern Taiwan during Winter Monsoon and Local Pollution Episodes

“…On the other hand, the dominant PCDD/F congener at Urban Site 2 during LRT, LP, and the normal period was OCDD (26.1%-52.5%), with higher proportion of PCDDs than that of PCDFs during LRT (50.8%) and the normal period (59.9%), when PCDFs dominated during LP (60.2%). The results indicated that OCDD was the dominant PCDD/F congener at all three sampling sites during LRT, LP, and the normal period, which corresponded with findings of Coutinho et al (2007) and Zhang et al (2015). Moreover, the proportion of PCDFs was higher than that of PCDDs at all sites during LRT and LP and increased substantially during LP, largely because of emissions from industrial activity and pollutant accumulation (Lee et al, 2004).…”

“…By contrast, Background Site, which was located far from areas of human activities, had the lowest PM 2.5 concentration and PCDD/F concentration. Lower levels of PM 2.5 concentrations and PCDD/F concentrations associated with such geographical locations were also reported in China (Ding et al, 2013), the United States (Cleverly et al, 2007), and Portugal (Cleverly et al, 2007;Coutinho et al, 2007;Ding et al, 2013). PCDD/F concentration levels recorded at all the other sampling sites were lower than those reported in Portugal (49.8 fg I-TEQ m ) but similar to those reported in Argentina (39 ± 76 fg I-TEQ m -3 ) and Taiwan (34-53 fg I-TEQ m -3 ) (Coutinho et al, 2015;Cappelletti et al, 2016;Ho et al, 2016;Lee et al, 2016;Meng et al, 2016;Sun et al, 2017;Xing et al, 2017).…”

The winter effect on formation of PCDD/Fs in Guangzhou by vehicles: A tunnel study

“…During summer as more heating of daytime than cooling during shortened nights, the convective mixing layer starts shallow in the morning, but rapidly grows to its full extent in early afternoon. On the contrary, during winter as more cooling at night than heating during the shortened daytime, the convective mixing layer remains relatively stable (Coutinho et al, 2007). Hence, local emissions to the atmosphere will be less well dispersed during winter.…”

“…The ratio between winter (OctobereMarch) and summer (AprileSeptember) mean values of atmospheric I-TEQ concentrations was 3.90, calculated for the period 2002e2004. Coutinho et al (2007) found the average ratio of the combined PCDD/F concentrations between winter (OctobereMarch) and summer (AprileSeptember) was 3.30 at most. Sin et al (2002) measured 27 ambient air samples in Hong Kong.…”

“…The former generally refers to higher emission of home heating in the winter and faster PCDD/F degradation rates in the summer. The latter is related to the seasonal variation of the atmospheric boundary layer generally referred to as the mixing layer (Coutinho et al, 2007). In a typical region of mid latitude, the heights of the convective mixing layer are very different between summer and winter.…”