Children and Air Pollution

This page last reviewed April 14, 2016


hands holding globe

When it comes to air pollution-related health effects, children are not simply miniature adults.  Children are often at greater risk from inhaled pollutants, due to the following reasons:

  • Children have unique activity patterns and behavior.  For example, they crawl and play on the ground, amidst dirt and dust that may carry a wide variety of toxicants. They often put their hands, toys, and other items into their mouths, ingesting harmful substances.  Compared to adults, children typically spend more time outdoors and are more physically active.  Time outdoors coupled with faster breathing during exercise increases children’s relative exposure to air pollution.
  • Children are physiologically unique.  Relative to body size, children eat, breathe, and drink more than adults, and their natural biological defenses are less developed.  The protective barrier surrounding the brain is not fully developed, and children’s nasal passages aren’t as effective at filtering out pollutants.  Developing lungs, immune, and metabolic systems are also at risk.
  • Children are particularly susceptible during development.  Environmental exposures during fetal development, the first few years of life, and puberty have the greatest potential to influence later growth and development. 

The Research Division of the Air Resources Board has funded a number of studies focused on increasing our understanding of how air pollution exposure impacts children's health. One of the largest and most in-depth studies ever conducted on long-term air pollution and children’s respiratory health, the Children’s Health Study (CHS), received funding from ARB.  The study, performed by University of Southern California (USC) researchers, examined whether long-term exposure to ambient ozone, particulate matter (PM), nitrogen dioxide (NO2) and strong acid vapor were responsible for chronic respiratory health problems in children in Southern California.  The National Institutes of Health (NIH) began funding the CHS in 2005. Under NIH funding the study has investigated the effect of air pollution on a variety of additional health endpoints, including, among others, birth outcomes, the effect of in-utero exposure on asthma risk, the respiratory effects of exposure to traffic-related pollution, and whether there are genetic variants that predispose individuals to air pollution-related health effects.  This study has been influential in ensuring that ambient air quality standards, both national and state, adequately protect the health of children. Click on these links for the final report and associated publications, a fact sheet with more information about the study, and the USC Children’s Health Study website.

The links in the table below will take you to information on several recent ARB—funded studies on the effects of air pollution on children.

Click here for a complete list of ARB-funded studies investigating children’s health and exposure.  The list includes links to a summary of each study, the study final report, and peer-reviewed publications that are based on the study. 

Recent ARB-Funded Research on Children and Air Pollution

Risk of pediatric asthma morbidity from multipollutant exposures

This study found that emergency department visits and hospital admissions for asthma increased in children who experienced higher levels of PM2.5 and ozone exposure in summer, and higher levels of carbon monoxide, NO2, and NOx exposure in winter. Hispanic and African American children and those without private insurance tended to live in areas with higher levels of traffic-related air pollution. 
Traffic-related air pollution and asthma in economically disadvantaged and high traffic density neighborhoods in Los Angeles County, California Higher levels of exposure to traffic air pollution increased the likelihood that a child had doctor-diagnosed asthma, used asthma medication, and had current wheeze, wheeze during the past year, or reduced measures of lung function. Children living in lower socioeconomic status neighborhoods had greater risk than those in more affluent neighborhoods. Differences between the responses of girls and boys suggest that gender may influence susceptibility to air pollution.
Traffic pollution and children’s health:  refining estimates of exposure for the East Bay children’s respiratory health study This was a study of children living at varying distances from high-traffic roads in Alameda County, California, a highly urbanized region characterized by good regional air quality due to coastal breezes. The highest risks of asthma were among those living within 75 m of a freeway/highway and those exposed to high levels of nearby traffic density. The findings support the conclusion that even in an area with good regional air quality, proximity to traffic is associated with adverse respiratory health effects in children.
Fresno Asthmatic Children's Environment Study (F.A.C.E.S.) The results from this study suggest an association between exposure to NO2 and both short and long-term reductions in lung function. Exposure to traffic derived air pollution was also associated with reduced lung function. Lung function tended to be better in children that lived further from busy roads, indicating that exposure to traffic-related air pollution could negatively impact lung function.
Huntington Park Asthma Study The study found that Hispanic children with asthma living in a lower socioeconomic area had a significant increase in asthma symptoms with exposure to ambient volatile organic compounds, which in urban areas largely results from the combustion and evaporative processes associated with vehicle use. The findings suggested that the inflammatory and irritant nature of traffic-related pollutants can lead to adverse health effects in asthmatic children.

Recent Children's Exposure Studies

Characterizing the Range of Children’s Pollutant Exposures During School Bus Commutes This study made real-time measurements of pollutant concentrations inside diesel school buses that were operated under several common scenarios. The results showed that minimizing commute time, using the cleanest buses for the longest routes, and reducing bus caravanning and idling time will reduce children's exposure to bus-related pollutants.

Measurement of Breathing Rate and Volume in Routinely Performed Daily Activities

The purposes of this research were to determine the amount of air breathed by people during typical daily activities throughout the age range of young children to older adults. The results provide key inputs for estimation of people’s exposure to air pollution under a wide range of activities.
Study of Children's Activity Patterns This study evaluated the time-activity patterns of a group of California children through a daily diary that recorded time spent in various locations, along with the activity performed.  The results provide important inputs for exposure estimation in children based on age (0-2 years, 3-5 years, 6-8 years, and 9-11 years), gender, season of the year, and region of the state.

Study of Environmental Health Conditions in Portable Classrooms

This study assessed indoor air quality and environmental conditions in portable and traditional classrooms at a sample of California schools. The results showed that both types of classrooms exceeded many of the environmental standards and guidelines available.  The results have been instrumental in improving environmental conditions in schools statewide.

Environmental Exposures in Early Childhood Education Environments  

This study examined air pollution and contaminant levels in dust in child care and preschool facilities in California. The results showed that most contaminant levels were similar to those measured in other studies of schools and residences. Levels for most chemicals with health-based standards were usually below levels of concern. However, a few chemicals exceeded health guidelines and mitigation strategies may be warranted, especially for formaldehyde.

Children's Environmental Health Protection Program

Several of ARB’s programs also focus on children.  For example, SB25, The Children’s Environmental Health Protection Act, was passed by the California Legislature in 1999. The Act required that ARB, in partnership with the Office of Environmental Health Hazard Assessment, prioritize the state ambient air quality standards for subsequent review and updating.  The Act also required that ARB select six communities for enhanced air quality monitoring to determine whether or not the air quality monitoring network was adequately assessing the air pollution exposure of children.  In addition, the Act required ARB to identify additional toxic air contaminants that might differentially impact children, and then assess whether existing control measures were adequate to protect children.  If no control measures for a toxic air contaminant of concern were currently in place, ARB was directed to develop new regulations to reduce exposure. Please click here for more information about the Program.

General information and fact sheets related to children’s health and exposure

Information on other ARB activities related to children’s environmental health can be obtained through the links below.

For more information, please contact the ARB’s Public Information Office at (800) 242-4450.