Compostos Orgânicos Voláteis: Principais Precursores de Ozônio na Cidade de São Paulo

The main air quality problems registered in the in the city of São Paulo are caused by ozone (O3) concentrations. This study, which was carried out in the Brazilian Basic Sanitation Engineering Company (CETESB) monitoring station of air quality located in the University of Sao Paulo - USP, focused on the elucidation of the main volatile organic compounds (VOCs) ozone precursors in São Paulo atmosphere between January to December 2006. Seventy-eight samples of air were collected during the study period, which the ten most important compounds in the formation of O3 were but-1-ene (12%), propene (10%), ethylene (8%), p-xylene (7% ) buta-1,3-diene (6%), 1-ethyl-4-methylbenzene (4%), isoprene (4%), trans-but-2-ene (4%), 2-methyl-but-2-ene (4%) and cis-but-2-ene (3%). The most abundant classes concentration in the air were alkanes (45%), alkenes (26%), and aromatics (14%), aldehydes (13%) and alkadienes 2%.http://dx.doi.org/10.5902/2179460X13126O ozônio é o principal problema de poluição do ar na Cidade de São Paulo. Este estudo foi realizado em uma estação de monitoramento da qualidade do ar da CETESB localizada na cidade universitária, USP e enfoca a elucidação dos principais compostos orgânicos voláteis precursores de ozônio na atmosfera paulistana entre janeiro à dezembro de 2006. Foram coletadas 78 amostras durante o período em estudo, onde os 10 compostos mais importantes na formação de O3 foram: but-1-eno (12%), propeno (10%), eteno (8%), p-xileno (7%),buta-1,3-dieno (6%), 1-etil-4-metilbenzeno (4%), isopreno (4%), trans-but-2-eno (4%), 2-metil-but-2-eno (4%) e cis-but-2-eno (3%). As classes mais abundantes em concentração no ar foram os alcanos (45%), alcenos (26%), os aromáticos (14%), aldeídos (13%) e alcadienos 2%

Main ozone-forming VOCs in the city of Sao Paulo: observations, modelling and impacts

Submitted by Marco Antonio Oliveira da Silva ([email protected]) on 2017-09-14T12:48:14Z No. of bitstreams: 1 23026.pdf: 885206 bytes, checksum: 4ebd35f9ae057d4d176e511313c8f797 (MD5)Made available in DSpace on 2017-09-14T12:48:14Z (GMT). No. of bitstreams: 1 23026.pdf: 885206 bytes, checksum: 4ebd35f9ae057d4d176e511313c8f797 (MD5)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)High-ozone concentrations currently represent the main air pollution problem in the city of São Paulo, Brazil. To elucidate the main volatile organic compounds (VOCs), which act as ozone precursors, samples from air quality monitoring stations were evaluated. Thirty-five samples were collected in August–September of 2006 and 43 in July–August of 2008, when the consumption of ethanol was about 50%of the total fuel used in the São Paulo Metropolitan Area. Samples were collected using electropolished stainless canisters. Chemical analyses were performed on pre-concentrated samples followed by gas chromatograph with flame ionization and mass spectrometry detection. The incremental reactivity scale was used to rank the ozone precursors using the Ozone Isopleth Package for Research (OZIPR) trajectory model coupled with chemical mechanism Statewide Air Pollution Research Center (SAPRC). Sixty-nine species of VOCs were quantified, and the ten main ozone precursors identified in 2008 were as follows: formaldehyde (42.8 %), acetaldehyde (13.9 %) , ethene (12.2 %) , propene (5.1 %), 1- methylcyclopentene (3.0 %), p-xylene (2.4 %), 1-butene (2.1 %), trans-2-pentene (1.9 %), 2-methyl 2-butene (1.7 %) and trans-2-butene (1.6 %). Volatile organic compound mass distribution showed that in 2008 alkanes represented 46 % of the total VOCs, alkenes 27 %, aromatics 14 %, alkadienes 1% and aldehydes 12 %.FAPESP: 03/14125-8CNPq: 142777/2007-