Analysis of PM₁₀, PM_2.5, and PM_2.5–10Concentrations in Santiago, Chile, from 1989 to 2001

Abstract

Daily particle samples were collected in Santiago, Chile, at four urban locations from January 1, 1989, through December 31, 2001. Both fine PM with d a Ͻ2.5 m (PM 2.5 ) and coarse PM with 2.5Ͻd a Ͻ10 m (PM 2.5-10 ) were collected using dichotomous samplers. The inhalable particle fraction, PM 10 , was determined as the sum of fine and coarse concentrations. Wind speed, temperature and relative humidity (RH) were also measured continuously. Average concentrations of PM 2.5 for the 1989 -2001 period ranged from 38.5 g/m 3 to 53 g/m 3 . For PM 2.5-10 levels ranged from 35.8 -48.2 g/m 3 and for PM 10 results were 74.4 -101.2 g/m 3 across the four sites. Both annual and daily PM 2.5 and PM 10 concentration levels exceeded the U.S. National Ambient Air Quality Standards and the European Union concentration limits. Mean PM 2.5 levels during the cold season (April through September) were more than twice as high as those observed in the warm season (October through March); whereas coarse particle levels were similar in both seasons. PM concentration trends were investigated using regression models, controlling for site, weekday, month, wind speed, temperature, and RH. Results showed that PM 2.5 concentrations decreased substantially, 52% over the 12-year period (1989 -2000), whereas PM 2.5-10 concentrations increased by ϳ50% in the first 5 years and then decreased by a similar percentage over the following 7 years. These decreases were evident even after controlling for significant climatic effects. These results suggest that the pollution reduction programs developed and implemented by the Comisió n Nacional del Medio Ambiente (CONAMA) have been effective in reducing particle levels in the Santiago Metropolitan region. However, particle levels remain high and it is thus imperative that efforts to improve air quality continue.

Prevalence of Freshly Generated Particles during Pollution Episodes in Santiago de Chile

“…Currently, PM 2.5 annual concentration is over 2.2 times the Chilean standard (20 µg m -3 ), but the highest PM 2.5 levels are seen during winter (Koutrakis et al, 2005). During this period, it is also common to observe an increase in the number of children's respiratory decease's as well as other health problems, following a pollution event (Ilabaca et al, 1999).…”

“…This plan, which was completed on July 25, 1997, established specific emissions reduction targets for the most common pollutants such as particulate matter, PM 10 , ozone, O 3 , nitrogen oxides, NO x , sulfur dioxide, SO 2 and CO. This plan has been quite successful because PM 10 has decreased from 90 µg m -3 in 1997 to 60 µg m -3 in 2001 (Koutrakis et al, 2005). Since that year, the PM 10 fraction has remained approximately constant.…”

“…Since that year, the PM 10 fraction has remained approximately constant. However, this plan did not address the fine fraction of particulate matter, which during winter reaches levels much higher than the WHO recommendation (Koutrakis et al, 2005). In May of 2011 new regulations were enacted to control the fine fraction of particulate matter, PM 2.5 .…”

Efecto del tiempo de exposición a PM10 en las urgencias por bronquitis aguda

“…Debemos considerar que baja humedad en el ambiente, en general es factor para el agravamiento de los cuadros por enfermedad respiratoria baja, como la bronquitis. Aunque no tenemos una respuesta clara para la no-linealidad del efecto en la humedad en estos dos sectores, creemos en una relación con partículas secundarias, tal como el PM 2,5 .…”

“…Esta situación topográfica, sumada a los fenómenos de inversión térmica, genera una disminución de la dispersión vertical de los contaminantes en invierno, produciendo incrementos sostenidos de material particulado a baja altura 2 . Las estaciones localizadas en el sector Centro (Parque O'Higgins) y Oeste (Pudahuel) de la ciudad han reportado históricamente los niveles más altos de contaminación por partículas 3 .…”