We study whether long-term cumulative exposure to airborne small particulate matter (PM2.5) affects the probability that an individual receives a new diagnosis of Alzheimer's disease or related dementias. We track the health, residential location, and PM2.5 exposures of Americans aged sixty-five and above from 2001 through 2013. The expansion of Clean Air Act regulations led to quasi-random variation in individuals’ subsequent exposures to PM2.5. We leverage these regulations to construct instrumental variables for individual-level decadal PM2.5 that we use within flexible probit models that also account for any potential sample selection based on survival. We find that a 1 µg/m3 increase in decadal PM2.5 increases the probability of a new dementia diagnosis by an average of 2.15 percentage points (pp). All else equal, we find larger effects for women, older people, and people with more clinical risk factors for dementia. These effects persist below current regulatory thresholds.

We use administrative and survey-based micro data to study the relationship between cognitive abilities (IQ), the formation of inflation expectations, and the consumption plans of a representative male population. High-IQ men display 50 % lower forecast errors for inflation than other men. High-IQ men, but not others, have consistent inflation expectations and perceptions over time. In terms of choice, only high-IQ men increase their consumption propensity when expecting higher inflation as the consumer Euler equation prescribes. Education levels, income, other expectations, and socio-economic status, although important, do not explain the variation in expectations and choice by IQ. Recent modelling attempts to incorporate boundedly rational agents into macro models do not fully capture all the facts we document. We discuss which dimensions of expectations formation and choice are important for heterogeneous-agents models of household consumption and for the transmission of fiscal and monetary policy.