Analysis of PM2.5 concentrations under pollutant emission control strategies in the metropolitan area of São Paulo, Brazil.

Great efforts have been made over the years to assess the effectiveness of air pollution controls in place in the metropolitan area of São Paulo (MASP), Brazil. In this work, the community multiscale air quality (CMAQ) model was used to evaluate the efficacy of emission control strategies in MASP, considering the spatial and temporal variability of fine particle concentration. Seven different emission scenarios were modeled to assess the relationship between the emission of precursors and ambient aerosol concentration, including a baseline emission inventory, and six sensitivity scenarios with emission reductions in relation to the baseline inventory: a 50% reduction in SO2 emissions; no SO2 emissions; a 50% reduction in SO2, NOx, and NH3 emissions; no sulfate (PSO4) particle emissions; no PSO4 and nitrate (PNO3) particle emissions; and no PNO3 emissions. Results show that ambient PM2.5 behavior is not linearly dependent on the emission of precursors. Variation levels in PM2.5 concentrations did not correspond to the reduction ratios applied to precursor emissions, mainly due to the contribution of organic and elemental carbon, and other secondary organic aerosol species. Reductions in SO2 emissions are less likely to be effective at reducing PM2.5 concentrations at the expected rate in many locations of the MASP. The largest reduction in ambient PM2.5 was obtained with the scenario that considered a reduction in 50% of SO2, NOx, and NH3 emissions (1 to 2 µg/m3 on average). It highlights the importance of considering the role of secondary organic aerosols and black carbon in the design of effective policies for ambient PM2.5 concentration control.

Digestibility of canola seeds treated by autoclaving and/or condensed tannins / Digestibilidad de la canola tratada en autoclave y/o con taninos condensados / Digestibilidade de grãos de canola tratados em autoclave e/ou com tanino condensado

Background: plant proteins are susceptible to rapid degradation in the rumen therefore it is important to explore the best way to improve protein utilization. Objective: to evaluate the effect of heat treatment and/ or condensed tannins on ruminal degradability and in vitro digestibility of crude protein (CP) and dry matter (DM) of canola seeds. Methods: in situ and in vitro DM and CP digestibility of canola seeds treated with water (control; CCL), heat in autoclave (CLE), condensed tannin (CTN), and condensed tannin followed by autoclaving (CTA) were evaluated. Results: the DM effective degradability values (EDDM) by CCL, CLE, CTN, and CTA were 66.8%, 73.6%, 58.5%, and 77.5%, respectively. Effective degradability of crude protein (EDCP) by CCL, CLE, CTN, and CTA at a 5%/h passage rate (k) was 75.2, 77.2, 60.2, and 80.5%, respectively. Addition of condensed tannin and/or autoclaving reduced both DM and CP digestibility. Conclusions: treatment with condensed tannins protected canola seeds DM and CP from ruminal degradability, while treatment with heat or tannins combined with heat showed the opposite effect, increasing degradability of those fractions. Addition of condensed tannins and/or autoclaving decreased in vitro DM and CP digestibility.

Antecedentes: es importante estudiar la mejor manera de utilizar fuentes de proteínas vegetales, ya que son rápidamente degradadas en el rumen. Objetivo: evaluar el efecto del tratamiento térmico y/o adición de taninos condensados sobre la degradabilidad ruminal y digestibilidad in vitro de la proteína bruta (PB) y la materia seca (MS) en granos de canola. Métodos: se evaluó la degradabilidad in situ y la digestibilidad in vitro de la MS y PB en granos de canola tratados con agua (control - CCL), térmicamente utilizando autoclave (CTE), taninos condensados (CTN), y taninos condensados seguido por autoclavado (CTA). Resultados: los valores de degradabilidad efectiva de la materia seca (DEMS) para CCL, CTE, CTN, y CTA fueron 66,8, 73,6, 58,5 y 77,5% respectivamente; y para la degradabilidad efectiva de la proteína bruta (DEPB ) fueron 75,2, 77,2, 60,2 y 80,5%, respectivamente -a una tasa de pasaje (k) de 5%/h. La adición de taninos condensados y/o tratamiento térmico provocó la reducción de los valores de digestibilidad, tanto de la MS como de la PB. Conclusiones: el tratamiento con taninos condensados protegió la MS y la PB de las semillas de canola de su degradación ruminal. Los tratamientos con calor húmedo y asociación taninos más calor mostraron el efecto contrario, promoviendo el aumento de la degradabilidad ruminal de esas fracciones. La adición de taninos condensados y/o el autoclavado resultaron en menores valores de digestibilidad para la MS y PB.

Antecedentes: é importante estudar a melhor maneira de utilizar as fontes de proteína vegetal, uma vez que essas são normalmente degradadas no rúmen. Objetivo: avaliar o efeito do tratamento térmico e/ou a adição de tanino condensado sobre a degradabilidade ruminal in situ e a digestibilidade in vitro da proteína bruta (PB) e da matéria seca (MS) de grãos de canola. Métodos: avaliou-se neste trabalho a degradabilidade in situ e a digestibilidade in vitro da MS e PB de grãos de canola tratados com água (controle - CCL), termicamente em autoclave (CTE), tanino condensado (CTN) e tanino condensado seguido de autoclave (CTA). Resultados: os valores de degradabilidade efetiva da matéria seca (DEMS) para CCL, CTE, CTN e CTA foram 66,8; 73,6; 58,5 e 77,5% respectivamente, e para a degradabilidade efetiva da proteína bruta (DEPB) foram 75,2; 77,2; 60,2 e 80,5%, para taxa de passagem (k) igual a 5%/h. A adição de tanino condensado e/ou tratamento com autoclave provocaram a diminuição da digestibilidade, tanto da MS como da PB. Conclusões: concluiu-se que o tratamento com tanino condensado promoveu efetiva proteção da MS e PB dos grãos de canola frente à degradabilidade no rúmen. Já o tratamento com calor úmido e a associação tanino-calor, mostraram efeito contrário, promovendo aumento da degradabilidaderuminal dessas frações. A adição de tanino condensado e/ ou tratamento com autoclave diminuíram a digestibilidade da MS e da PB.