Air pollution levels in the City of Buenos Aires

Monitoring of air quality in the City of Buenos Aires and in the Metropolitan Area of Buenos Aires (MABA) has been rare and sporadic. Therefore, no reliable information exists of the current main sources of pollution nor of which are the most common contaminants and their concentrations (WHO, 1992). It is assumed here that the City of Buenos Aires presents the same characteristics as other mega-cities of the world, being auto-transportation the main source of pollution. High concentrations for Pb, CO, O₃, particulated carbon, NO_X and SO_X may be expected. Thanks to its geographical and climatic conditions, the situation is not as critical as in other mega-cities. There are long-term data series for 1968-1973 from six stations (REDPANAIRE, OMS, 1974). The concentrations of SPM (suspended particle matter) and SH₂ were within the WHO guidelines, except for some extreme daily means. In 1985 and 1986, the GEMS (Global Environmental Monitoring System, WHO) measured concentration of suspended particles in two places in the city. For some of the measurements the average and the daily maximum concentrations exceeded the WHO guidelines. A study of air pollution from auto-transportation was made between 1974 and 1977. Only 20 different sites were used from the 4 campaigns, half of them with heavy traffic. It was concluded that average concentrations for CO, SO₂ y NO_X in the centric area were significantly higher than those found in the industrial area. Regarding oxidants and O₃ the average concentrations were significantly greater for the industrial area than for the centric area. Caridi et al. (1989) found out that typical concentration for Pb in the suburban areas was 0.3  g/m³ and 3.9  g/m³ in centric areas of the city. The average time of sampling is not specified. En 1994, sampling was made in 19 stations for NO_X and SO₂ in the city, between May 25 and July 13 (Aramendía et al., 1995). For NO_X concentrations varied between 0.027 ppm and 0.047 ppm, and for SO₂, between 0.002 ppm y 0.008 ppm. The higher values correspond to centric area, but are below the maximum tolerable limits established by EPA (Environmental Protection Agency, USA). No significant seasonal variations were noticed. The method used concealed the presence of peaks. Air was sampled for aerosols in the centric area. In 15% of the few samples taken the amount was higher than acceptable, according to limits established by EPA. Currently, there is one monitoring station located in the centric area of the city, that measures only CO. The curve of the daily variation of CO concentration shows to maximum peaks, corresponding to morning and evening rush-hours. The greatest peak is the one between 8:00 and 11:00 a.m. with concentrations between 11.0 and 17.00 ppm, while during weekends and holidays it decreases to 1.0 to 4.0 ppm (La Nación, 1994-1995). The WHO guidelines recommend 9 ppm as maximum CO concentration for 8 hour exposure. The Municipal government has a station in another site where average concentrations of NO_X, SO₂ and particles do not exceed the limits of 0.1 mg/m3, 0.07 mg/m3 and 0.150 mg/m3 respectively, established by local legislation for long periods of time.

References

ARAMENDÍA, P. F.; FERNÁNDEZ PRINI, R.; GORDILLO, G; 1995. ¿Buenos Aires en Buenos Aires?. Ciencia Hoy 6 (31): 55-64.

CARIDI, A.; KREINER, A. J.; DAVIDSON, J.; DAVIDSON, M.; DEBRAY, M.; HOJMAN, D.; SANTOS, D.; 1989. Determination of Atmospheric Lead Pollution of Automotive Origin. Atmospheric Environment 23: 2855-2856.

LA NACION, 1994-1995. Periódico matutino; Buenos Aires, Argentina.

OMS; 1974. Red panamericana de muestreo de la contaminación del aire. División Salud Ambiental. Serie técnica 18. OPS.

WHO-UNEP. 1992. EARTHWATCH (Global Environmental Monitoring System): Urban Air Pollution in Megacities of the World. Blackwell Publishers, U.K..