Abstract: Entrepreneurial activity is a crucial pillar for strengthening local economic development and driving regional economic growth When firms choose a city for registration and location，they consider not only the impact of air pollution on their economic benefits but also the environmental constraints imposed by pollution control measures Indepth research on the relationship between air pollution and firm entry is vital for analyzing the environmental factors that influence firm decisionmaking
In this context，this paper focuses on the impact of air pollution on firm entry Specifically，it measures air pollution using PM25 and utilizes a panel dataset of monthly firm registration information from 2001 to 2020，matched with countylevel air pollution data across the country The study employs the meteorological phenomenon of thermal inversion as an instrumental variable for air pollution to alleviate endogeneity issues and empirically investigates the effect of air pollution on firm entry The results indicate that air pollution has a significant inhibitory effect on firm entry，with each unit increase in air pollution concentration leading to a 08% decrease in firm entry Further analysis reveals that the impact of air pollution on firm entry exhibits significant heterogeneity depending on employee labor productivity and the level of regional environmental regulation： the inhibitory effect of air pollution is more pronounced for firms with high labor productivity and in regions with low environmental regulation
Compared to existing literature，the main contributions of this paper are as follows： First，this study expands the research on the economic effects of air pollution by examining how air pollution affects firm dynamics Additionally，by consistently using the meteorological phenomenon of thermal inversion as an instrumental variable in all regressions，the study integrates meteorological elements into economic activity research，not only mitigating potential endogeneity issues but also reflecting the innovation of crossdisciplinary research，thereby enhancing the studys credibility and accuracy
Second，the paper extends the research on the factors influencing firm entry By incorporating air pollution，a natural environmental factor，into the same analytical framework with firm entry and revealing the specific logic of how air pollution affects firm behavior through heterogeneity analysis，the study provides a theoretical reference for further enhancing regional entrepreneurial vitality
The conclusions of this study reveal the harm of air pollution from a microeconomic perspective and offer effective insights for governments in formulating and implementing comprehensive air pollution control policies to achieve the dual goals of environmental protection and economic development

Key words: air pollution, firm entry, labor productivity, environmental regulations

摘要： 空气污染不仅会损害人体健康，也会影响企业的决策与行为，从而对微观经济产生重要影响。明确空气污染对企业进入的作用有助于更好地理解空气污染的经济效应。本文基于2001—2020年区县级月度面板数据，采用气象学逆温现象作为工具变量来缓解内生性问题，系统地考察了空气污染对企业进入的影响。研究发现，PM25浓度每升高1个单位，会使企业进入数量降低08%，稳健性检验依然支持该结论。进一步分析表明，空气污染对企业进入的影响在不同的员工劳动生产率和地区环境规制水平下具有明显异质性。本文的研究结论从微观经济视角揭示了空气污染的危害，为政府制定和实施空气污染综合治理政策、实现环境保护与经济发展双重目标提供了有效借鉴。 

关键词: 空气污染, 企业进入, 劳动生产率, 环境规制