How many Americans could breathe unhealthy air by 2100?
Climate-driven air quality: a sevenfold jump in unhealthy exposure
New modeling indicates that by the year 2100, nearly one in three Americans could routinely breathe air considered unhealthy for people with sensitivity—an increase described as about seven-fold compared with today. The projections tie the change directly to climate-driven shifts that degrade smog-season air quality.
The analysis frames the risk around exposure conditions averaged across periods when smog is most problematic. In that context, climate change is expected to worsen the frequency and severity of unhealthy air episodes, so that more people spend more time living in areas where air quality triggers guidance for vulnerable groups to limit time outdoors.
Why it matters:
- Air pollution is linked to respiratory and cardiovascular harm.
- “Sensitive people” often include those with asthma, chronic lung disease, and other underlying vulnerabilities.
- If unhealthy air becomes routine, health impacts could scale with the number of people exposed.
What the study suggests for public health and planning:
- Broader portions of the population may need to prepare for smog-season risks.
- Cities and states may need to strengthen air-quality management to prevent projected worsening.
- Long-term adaptation may require both emissions controls and targeted protections for vulnerable groups.
Overall, the result emphasizes that climate change isn’t only a temperature story; it also functions as an air-quality amplifier. As warming reshapes atmospheric chemistry and weather patterns, the model forecasts a substantial expansion of the geography where smog-season pollution levels could be unhealthy much more often—potentially affecting health outcomes nationwide as the century progresses.