Inner-city children have high rates of asthma. Exposures to particles, including allergens, may cause or
exacerbate asthma symptoms. As part of an epidemiologic study of inner-city children with asthma,
continuous (10-min average) measurements of particle concentrations were made for 2-week periods in
294 homes drawn from seven cities. Measurements were made using an optical scattering device that is
most sensitive to fine particles