Children's Health Study

The Children's Health Study (CHS) is one of the largest and most comprehensive investigation of the long-term effects of air pollution on the respiratory health of children. More than 11,000 schoolchildren living in southern california are involved in this ongoing cohort study. The CHS overall objective are to investigate the etiology of childhood respiratory diseases and the antecedent of adult respiratory diseases with special emphasis on the long-term health effects of air pollution on children.


Key research findings show that:

Current levels of air pollution have chronic,adverse effects on lung growth leading to clinically significant deficit in 18-year-old children. Air pollution affects both new onset asthma and exacerbation. Living in close proximity to busy roads is associated with with risk for prevalent asthma. Residential traffic exposure is linked to deficit in lung function growth and increased school absences. Differences in genetic makeup affect these outcomes.

The CHS findings provide scientific support for aggressive efforts to achieve clean air. Study results are widely publicized so that the public understands their significance,and the public policy decisions take the results into consideration.The CHS results have have led to changes in state and federal regulatory standards for particulate matter, a demand for clean air action programs at ports in california, and a greater awareness of "health" as a concern in the transportation planning process.

Visit Press Stories for recent research results from the Children's Health study.


At study initiation in 1993, 4,000 children from 4th, 7th,and 10th grade classrooms in 12 communities within southern California were recuited. Study sites within the southern California region were selected with in the aim of maximizing variability and minimizing the correlations in our pollutants of interst, based on historic routine air monioring data and and specialized monitring studies. In regions with pollution patterns of interest,cities or neighborhoods with stable, largely middle-income populations,ethically representative of southern California as a whole, were identified from 1990 census data..

In 1996, an additional 2,000 fourth-grade schoolchildren were recruited. These children replaced those who had since graduated from the previous cohort recruited in 1993 and were similar in demographics.

Our most recent cohort of 5,341 kindergarten and 1st grade children was recruited in 2002 from school in 13 southern California communities. Nine communities wrerthe same as in the orignal CHS cohorts, and 4 were new in order to establish a more ethically diverse study population,

Questionnaires and Health Measurements. Three approaches have been used in the CHS to assess health effects, to collect information on personal characterstics, (2) pulmonary function testing from collecting of buccal cells for DNA samples,and (3) exhaled NO measurement (FeNO). Data are collected at school during morning visists by field teams consisting of two to six members.