Sunday, September 18, 2005

Strike Reduces Pollution

BrooklynDodger blogs this abstract because it echoes the Pope study of air pollution in Utah: there the strike shut down a steel mill, here the strike shut down the busses. The investigators cite one study by Pope, but not the strike study.

BrooklynDodger personally has observed Sao Paulo busses, plumes of black smoke at street level are the rule, not the exception.

BrooklynDodger notes that busses are not the only source of pollution in SP. Also, the Dodger warns that mutagenicity of particles may not be the primary mechanism by which diesel particulate matter causes lung cancer.

Environmental Research 98 (2005) 1–7
Diesel emissions significantly influence composition and mutagenicity of ambient particles: a case study in Sao Paulo, Brazil
R. Carvalho-Oliveira,a R.M.K. Pozo,a D.J.A. Lobo,a A.J.F.C. Lichtenfels,a
H.A. Martins-Junior,b J.O.W.V. Bustilho,b M. Saiki,b I.M. Sato,b and P.H.N. Saldivaa,_
aLaboratory of Experimental Air Pollution, Department of Pathology, School of Medicine, Faculty of Medicine, University of Sa˜o Paulo,
Av. Dr. Arnaldo 455, CEP 01246-903 Sao Paulo, SP, Brazil
bInstitute of Energetic and Nuclear Research, University of Sa˜o Paulo, Av. Professor Lineu Prestes, 2242, CEP 05508-000 Sa˜o Paulo, SP, Brazil

In 2003, a bus strike paralyzed the fleet of buses in Sao Paulo, Brazil during 3 days, from 6 to 8 of April, the complete interruption of services being achieved on the 7th. We evaluated the effect of the absence of this source of pollution on the composition, mutagenicity, and toxicity of the fine particulate material collected during this period. Particles were sampled in glass fiber filters on days 7 and 15 of April of 2003 (strike and nonstrike days, respectively), using a high-volume sampler. Trace element determinations (As, Br, Co, Cl, Fe, La, Mn, Sb, Sc, and Th) of particulate material samples were carried out by neutron activation analysis. Sulfur determination was done by X-ray fluorescence analysis. The ratio between nonstrike/strike concentrations of hydrocarbons associated with automotive emissions (benzene, toluene, ethyl-benzene, and xylenes; BTEX) was determined by gas chromatography/mass spectrometry. Mutagenesis of testing solutions was determined by means of the Tradescantia micronucleus assay in early tetrads of Tradescantia pallida. The inhibition of mitosis of the cells of the primary meristema of the root tips of Allium cepa was used as an index of the toxicity. Fine particle trace element contents were lower during the strike. The concentrations of sulfur and BTEX were 50% and 39.3% lower, respectively, on the strike day. A significant (P < .038) reduction of micronuclei induced by fine particles sampled during the strike was observed. No effect of the strike on toxicity was detected. These results indicate that a program aiming to reduce emissions of the bus fleet in our town may impact positively the air quality by reducing the mutagenic potential of ambient particles.

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