Cramer J C
Department of Sociology, University of California at Davis 95616, USA. JCRAMER@UCDAVIS
Demography. 1998 Feb;35(1):45-56.
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.
人口统计学家常常对人口增长的环境影响感兴趣。我专门研究增长对加利福尼亚空气质量的影响。近几十年来，加利福尼亚饱受空气污染之苦，且经历了人口的快速增长。尽管人口在增长，但由于积极的监管措施，自20世纪80年代初以来空气质量实际上已有改善。利用56个县的数据，我分析了1980年至1990年人口增长对五种受管制污染物大气排放趋势的贡献，同时控制人均收入趋势和监管措施。该分析按排放源进行了细分，结果表明人口增长与某些排放源密切相关，但与其他排放源无关。因此，人口增长的总体影响取决于每个县生产和消费活动的构成。我还探讨了家庭数量趋势是否比人口数量趋势更具预测性，以及人口增长的影响是否取决于年龄结构或增长来源（移民或国内增长）。一般来说，这些人口的替代指标并没有改善大气排放模型。
