Sampling of respirable particle PM₁₀in the library at the Metropolitana University, Campus Azcapotzalco, Mexico City

Abstract

This study presents the results of a sampling campaign of PM 10 respirable particles, carried out at the library located in the Metropolitana University, Campus Azcapotzalco, through seven months: March, April, May, June, July, September and October, 2005. We collected a total of 84 samples, considering only the three main levels of the Library and selecting a total of nine sampling points. The other levels are located at the mezzanine and the main entrance, where there is no rug and the floor is cleaned up daily with a wet cloth. Samplings were carried out for nine weeks, three weeks for each level, so finally, we ended up with 18 samples for level 1, 27 for level 2, and 36 for level 3; plus three reference samples. Samples were collected using a set of sampling pumps SKC for indoor sampling, from 10:00 a.m. to 6:00 p.m. on Monday, Wednesday, and Friday. Three reference samples were collected on Thursday, when there is less activity in the Library. In level 1, where there is a study area, the minimum mass concentration of R.P. was 15.27 µg/m 3 . This area has no rug and it is near the main entrance. The maximum mass concentration of R.P. was 131.94 µg/m 3 for the same level, in a sampling point located in a corner far from the entrance. For level 2, the minimum concentration of R.P. was 8.33 µg/m 3 , on the shelves T-J, and the maximum concentration of R.P. was 157.77 µg/m 3 , on the shelf Q. This difference in concentration between the two sampling points could have been originated due to the type of books on the shelves, which are demanded more by the students. It is important to point out that this level has an old rug. In level 3, the minimum concentration of R.P. detected was 6.94 µg/m 3 , in the sampling point of the F shelf, and the maximum concentration, on the shelves H-T, was 197.22 µg/m 3 . The difference in concentrations may be due to the subjects of the books on each shelf and the interest of students for those booksso there are more people going in and out -also, in this level there is an old rug that is usually cleaned using a vacuum cleaner, but not very often. This type of cleaning is the same for level 2. It is important to point out that the library building does not have any air conditioning or air movers.