Demographers are often interested in the environmental impacts of population growth. I examine the impact of growth specifically on air quality in California. In recent decades, California has suffered from notoriously polluted air and has experienced rapid population growth. Despite the population growth, air quality actually has improved since the early 1980s due to aggressive regulatory efforts. Using data for 56 counties, I analyze the contribution of population growth to trends in atmospheric emissions of five regulated pollutants from 1980 to 1990, controlling for trends in per capita income and regulatory efforts. The analysis is disaggregated by source of emissions and demonstrates that population growth is strongly associated with some sources of emissions but not with others. Thus, the overall impact of population growth depends upon the composition of production and consumption activities in each county. I also explore whether the trend in number of households predicts better than the trend in number of persons, and whether the impact of population growth depends upon the age structure or source of growth (immigration or domestic increase). Generally, these alternative specifications of population do not improve the models of atmospheric emissions.

No abstract

This paper attempts to explain the differences in birthweight observed between blacks, white Anglos, Chicanos, and other racial and ethnic groups. The analysis focuses on the role of income and financial assistance from relatives and public programs. Using data from the NLS Youth Panel, I construct a casual model of birthweight containing exogenous social and demographic risk factors and intervening proximate determinants of birthweight. A substantial part of the gap in birthweight between white Anglos and other ethnic groups (especially blacks) can be explained by the unfavorable socioeconomic and demographic characteristics of the latter. On the other hand, blacks and other minorities smoke less and have other favorable proximate characteristics that depress differences in birthweight. When these proximate determinants are controlled, large ethic differences in birthweight remain unexplained by income and other sociodemographic factors.

No abstract

No abstract