12,000

We have over 12,000 students, from over 100 countries, within one of the safest campuses in the UK

93%

93% of Lancaster students go into work or further study within six months of graduating

Home > Research > Publications & Outputs > Observations on PAH, PCB and PCDD/F trends in U...
View graph of relations

« Back

Observations on PAH, PCB and PCDD/F trends in UK urban air, 1991-1995.

Research output: Contribution to journalJournal article

Published

Journal publication date07/1997
JournalEnvironmental Science and Technology
Journal number7
Volume31
Number of pages5
Pages2120-2124
Original languageEnglish

Abstract

Ambient air concentrations at London and Manchester are reported for PCBs, PAHs, and PCDD/Fs from 1991 to 1995. This data set suggests that urban PAH concentrations are trending downward in the U.K. ∑PCB concentrations (∑ = congeners 28, 52, 101, 118, 138, 153, and 180) were usually 0.2−2 ng m-3 over the study period, with concentrations of the seven PCB congeners (∑PCB) in London generally 2−3 times higher than in Manchester. PCB concentrations have remained quite stable year-on-year over the study period. PCDD/F trends at the two sites were similar, with a decline through 1991−1994, followed by an upturn in 1995. Summer:winter seasonality of PCDD/Fs at both sites has been highly erratic year-on-year and compound-by-compound, far more so than for PAHs and PCBs. This is perhaps best interpreted as a sign that various sources (presumably combustion-derived) have contributed different mixtures of PCDD/Fs of different source strengths at different times to the air at these urban sites. Possible causes are discussed.